Статті в журналах: "X-ray photons"

1

Reusch, Tobias, Markus Osterhoff, Johannes Agricola, and Tim Salditt. "Pulse-resolved multi-photon X-ray detection at 31 MHz based on a quadrant avalanche photodiode." Journal of Synchrotron Radiation 21, no. 4 (June 3, 2014): 708–15. http://dx.doi.org/10.1107/s1600577514006730.

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The technical realisation and the commissioning experiments of a high-speed X-ray detector based on a quadrant avalanche silicon photodiode and high-speed digitizers are described. The development is driven by the need for X-ray detectors dedicated to time-resolved diffraction and imaging experiments, ideally requiring pulse-resolved data processing at the synchrotron bunch repetition rate. By a novel multi-photon detection scheme, the exact number of X-ray photons within each X-ray pulse can be recorded. Commissioning experiments at beamlines P08 and P10 of the storage ring PETRA III, at DESY, Hamburg, Germany, have been used to validate the pulse-wise multi-photon counting scheme at bunch frequencies ≥31 MHz, enabling pulse-by-pulse readout during the PETRA III 240-bunch mode with single-photon detection capability. An X-ray flux of ≥3.7 × 109 photons s−1can be detected while still resolving individual photons at low count rates.

2

Zhao, Di, Pengxian You, Jing Yang, Junhong Yu, Hang Zhang, Min Liao, and Jianbo Hu. "A Highly Stable-Output Kilohertz Femtosecond Hard X-ray Pulse Source for Ultrafast X-ray Diffraction." Applied Sciences 12, no. 9 (May 7, 2022): 4723. http://dx.doi.org/10.3390/app12094723.

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Femtosecond hard X-ray pulses generated by laser-driven plasma sources are eminently suitable to probe structural dynamics due to the angstrom spatial resolution and sub-picosecond time resolution. However, the insufficient flux of X-ray photons and high pulse-to-pulse instability compared with the large-scale ultrashort X-ray source, such as X-ray free-electron laser and synchrotrons, largely restricts its applications. In this work, we have optimized automation control and mechanical designs to significantly enhance the reliability and photon flux in our femtosecond laser plasma-induced X-ray source. Specifically, the optimized source provides a reliable pulse-to-pulse stability with a fluctuation of less than 1% (root-mean-square) and a total flux of Cu-Kα X-ray photons above 1011 photons/s. To confirm its functionality, ultrafast X-ray diffraction experiments are conducted on two different samples and the high consistency with previous results verifies the system’s superior performance.

3

Saá Hernández, Ángela, Diego González-Díaz, Pablo Villanueva, Carlos Azevedo, and Marcos Seoane. "A new imaging technology based on Compton X-ray scattering." Journal of Synchrotron Radiation 28, no. 5 (July 22, 2021): 1558–72. http://dx.doi.org/10.1107/s1600577521005919.

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A feasible implementation of a novel X-ray detector for highly energetic X-ray photons with a large solid angle coverage, optimal for the detection of Compton X-ray scattered photons, is described. The device consists of a 20 cm-thick sensitive volume filled with xenon at atmospheric pressure. When the Compton-scattered photons interact with the xenon, the released photoelectrons create clouds of secondary ionization, which are imaged using the electroluminescence produced in a custom-made multi-hole acrylic structure. Photon-by-photon counting can be achieved by processing the resulting image, taken in a continuous readout mode. Based on Geant4 simulations, by considering a realistic detector design and response, it is shown that photon rates up to at least 1011 photons s−1 on-sample (5 µm water-equivalent cell) can be processed, limited by the spatial diffusion of the photoelectrons in the gas. Illustratively, if making use of the Rose criterion and assuming the dose partitioning theorem, it is shown how such a detector would allow obtaining 3D images of 5 µm-size unstained cells in their native environment in about 24 h, with a resolution of 36 nm.

4

Song, Sanghoon, Roberto Alonso-Mori, Matthieu Chollet, Yiping Feng, James M. Glownia, Henrik T. Lemke, Marcin Sikorski, et al. "Measurement of the absolute number of photons of the hard X-ray beamline at the Linac Coherent Light Source." Journal of Synchrotron Radiation 26, no. 2 (February 11, 2019): 320–27. http://dx.doi.org/10.1107/s1600577519000250.

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X-ray free-electron lasers provide intense pulses of coherent X-rays with a short pulse duration. These sources are chaotic by nature and therefore, to be used at their full potential, require that every X-ray pulse is characterized in terms of various relevant properties such as intensity, photon energy, position and timing. Diagnostics are for example installed on an X-ray beamline to specifically monitor the intensity of individual X-ray pulses. To date, these can however only provide a single-shot value of the relative number of photons per shot. Here are reported measurements made in January 2015 of the absolute number of photons in the hard X-ray regime at LCLS which is typically 3.5 × 1011 photons shot−1 between 6 and 9.5 keV at the X-ray Pump–Probe instrument. Moreover, an average transmission of ≈62% of the hard X-ray beamline over this energy range is measured and the third-harmonic content of ≈0.47% below 9 keV is characterized.

5

Pickford Scienti, Oliver L. P. Pickford, and Dimitra G. Darambara. "Demonstrating a Novel, Hidden Source of Spectral Distortion in X-ray Photon Counting Detectors and Assessing Novel Trigger Schemes Proposed to Avoid It." Sensors 23, no. 9 (May 1, 2023): 4445. http://dx.doi.org/10.3390/s23094445.

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X-ray photon counting spectral imaging (x-CSI) determines a detected photon’s energy by comparing the charge it induces with several thresholds, counting how many times each is crossed (the standard method, STD). This paper is the first to demonstrate that this approach can unexpectedly delete counts from the recorded energy spectrum under some clinically relevant conditions: a process we call negative counting. Four alternative counting schemes are proposed and simulated for a wide range of sensor geometries (pixel pitch 100–600 µm, sensor thickness 1–3 mm), number of thresholds (3, 5, 8, 24 and 130) and medically relevant X-ray fluxes (106–109 photons mm−2 s−1). Spectral efficiency and counting efficiency are calculated for each simulation. Performance gains are explained mechanistically and correlated well with the improved suppression of “negative counting”. The best performing scheme (Shift Register, SR) entirely eliminates negative counting, remaining close to an ideal scheme at fluxes of up to 108 photons mm−2 s−1. At the highest fluxes considered, the deviation from ideal behaviour is reduced by 2/3 in SR compared with STD. The results have significant implications both for generally improving spectral fidelity and as a possible path toward the 109 photons mm−2 s−1 goal in photon-counting CT.

6

Feranchuk, Ilya D., Oleg D. Skoromnik, and Quang San Nguyen. "Method of the equivalent photons for modulated electron beam." Journal of the Belarusian State University. Physics, no. 3 (October 7, 2020): 24–31. http://dx.doi.org/10.33581/2520-2243-2020-3-24-31.

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It is shown in this work that electromagnetic self-field of the periodically density modulated electron bunch can be considered as the beam of the equivalent photons (pseudo-photons), collimated along the electron velocity. Pseudo-photon spectrum includes both the incoherent contribution being proportional to number of electrons in the bunch and the coherent part with the sharp maximum corresponding the modulation frequency. Method of the equivalent photons can be applied for description of the interaction between the electron bunch and a crystal that leads to generation of the coherent parametric X-ray radiation by the modulated bunches exited from the undulator of the X-ray free electron laser. It provides the possibility to obtain the X-ray pulses directed at the large angle to the electron velocity where intensity of the background radiation essentially decreased. It is defined the conditions when the spectral and angular distributions of the coherent pseudo-photons can be compared with the analogous values for the pulses of the X-ray laser.

7

Hu, Kun, Matthew G. Baring, Alice K. Harding, and Zorawar Wadiasingh. "High-energy Photon Opacity in the Twisted Magnetospheres of Magnetars." Astrophysical Journal 940, no. 1 (November 1, 2022): 91. http://dx.doi.org/10.3847/1538-4357/ac9611.

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Abstract Magnetars are neutron stars characterized by strong surface magnetic fields generally exceeding the quantum critical value of 44.1 TG. High-energy photons propagating in their magnetospheres can be attenuated by QED processes like photon splitting and magnetic pair creation. In this paper, we compute the opacities due to photon splitting and pair creation by photons emitted anywhere in the magnetosphere of a magnetar. Axisymmetric, twisted dipole field configurations embedded in the Schwarzschild metric are treated. The paper computes the maximum energies for photon transparency that permit propagation to infinity in curved spacetime. Special emphasis is given to cases where photons are generated along magnetic field loops and/or in polar regions; these cases directly relate to resonant inverse Compton scattering models for the hard X-ray emission from magnetars and Comptonized soft gamma-ray emission from giant flares. We find that increases in magnetospheric twists raise or lower photon opacities, depending on both the emission locale and the competition between field-line straightening and field strength enhancement. Consequently, given the implicit spectral transparency of hard X-ray bursts and persistent “tail” emission of magnetars, photon splitting considerations constrain their emission region locales and the twist angle of the magnetosphere; these constraints can be probed by future soft gamma-ray telescopes such as COSI and AMEGO. The inclusion of twists generally increases the opaque volume of pair creation by photons above its threshold, except when photons are emitted in polar regions and approximately parallel to the field.

8

Kutukova, Kristina, Bartlomiej Lechowski, Joerg Grenzer, Peter Krueger, André Clausner, and Ehrenfried Zschech. "Laboratory High-Contrast X-ray Microscopy of Copper Nanostructures Enabled by a Liquid-Metal-Jet X-ray Source." Nanomaterials 14, no. 5 (February 29, 2024): 448. http://dx.doi.org/10.3390/nano14050448.

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High-resolution imaging of Cu/low-k on-chip interconnect stacks in advanced microelectronic products is demonstrated using full-field transmission X-ray microscopy (TXM). The comparison of two lens-based laboratory X-ray microscopes that are operated at two different photon energies, 8.0 keV and 9.2 keV, shows a contrast enhancement for imaging of copper nanostructures embedded in insulating organosilicate glass of a factor of 5 if 9.2 keV photons are used. Photons with this energy (Ga-Kα radiation) are generated from a Ga-containing target of a laboratory X-ray source applying the liquid-metal-jet technology. The 5 times higher contrast compared to the use of Cu-Kα radiation (8.0 keV photon energy) from a rotating anode X-ray source is caused by the fact that the energy of the Ga-Kα emission line is slightly higher than that of the Cu-K absorption edge (9.0 keV photon energy). The use of Ga-Kα radiation is of particular advantage for imaging of copper interconnects with dimensions from several 100 nm down to several 10 nm in a Cu/SiO2 or Cu/low-k backend-of-line stack. Physical failure analysis and reliability engineering in the semiconductor industry will benefit from high-contrast X-ray images of sub-μm copper structures in microchips.

9

Lewis, Cale E., and Mini Das. "Spectral Signatures of X-ray Scatter Using Energy-Resolving Photon-Counting Detectors." Sensors 19, no. 22 (November 18, 2019): 5022. http://dx.doi.org/10.3390/s19225022.

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Energy-resolving photon-counting detectors (PCDs) separate photons from a polychromatic X-ray source into a number of separate energy bins. This spectral information from PCDs would allow advancements in X-ray imaging, such as improving image contrast, quantitative imaging, and material identification and characterization. However, aspects like detector spectral distortions and scattered photons from the object can impede these advantages if left unaccounted for. Scattered X-ray photons act as noise in an image and reduce image contrast, thereby significantly hindering PCD utility. In this paper, we explore and outline several important characteristics of spectral X-ray scatter with examples of soft-material imaging (such as cancer imaging in mammography or explosives detection in airport security). Our results showed critical spectral signatures of scattered photons that depend on a few adjustable experimental factors. Additionally, energy bins over a large portion of the spectrum exhibit lower scatter-to-primary ratio in comparison to what would be expected when using a conventional energy-integrating detector. These important findings allow flexible choice of scatter-correction methods and energy-bin utilization when using PCDs. Our findings also propel the development of efficient spectral X-ray scatter correction methods for a wide range of PCD-based applications.

10

Rinkel, Jean, Debora Magalhães, Franz Wagner, Florian Meneau, and Flavio Cesar Vicentin. "Detective quantum efficiency for photon-counting hybrid pixel detectors in the tender X-ray domain: application to Medipix3RX." Journal of Synchrotron Radiation 23, no. 1 (January 1, 2016): 206–13. http://dx.doi.org/10.1107/s1600577515020226.

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Synchrotron-radiation-based X-ray imaging techniques using tender X-rays are facing a growing demand, in particular to probe theKabsorption edges of low-Zelements. Here, a mathematical model has been developed for estimating the detective quantum efficiency (DQE) at zero spatial frequency in the tender X-ray energy range for photon-counting detectors by taking into account the influence of electronic noise. The experiments were carried out with a Medipix3RX ASIC bump-bonded to a 300 µm silicon sensor at the Soft X-ray Spectroscopy beamline (D04A-SXS) of the Brazilian Synchrotron Light Laboratory (LNLS, Campinas, Brazil). The results show that Medipix3RX can be used to develop new imaging modalities in the tender X-ray range for energies down to 2 keV. The efficiency and optimal DQE depend on the energy and flux of the photons. The optimal DQE values were found in the 7.9–8.6 keV photon energy range. The DQE deterioration for higher energies due to the lower absorption efficiency of the sensor and for lower energies due to the electronic noise has been quantified. The DQE for 3 keV photons and 1 × 104 photons pixel−1s−1is similar to that obtained with 19 keV photons. Based on our model, the use of Medipix3RX could be extended down to 2 keV which is crucial for coming applications in imaging techniques at modern synchrotron sources.

11

SAKAI, FUMIO, TERUNOBU NAKAJYO, TATSUYA YANAGIDA, and SHINJI ITO. "A COMPACT THOMSON X-RAY SOURCE AT SHI." International Journal of Modern Physics B 21, no. 03n04 (February 10, 2007): 465–72. http://dx.doi.org/10.1142/s0217979207042252.

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A compact, high-brightness x-ray source has been developed through Thomson scattering between photons and relativistic electrons. 33keV energy photons (maximum) were generated in a 165-degree interaction configuration with 38MeV electrons and 800nm-wavelength Ti :sapphire laser light. The number of total photons generated at an interaction point was 106 photons/pulse for a 0.8nC electron bunch charge and 150mJ laser pulse energy. In a 90-degree interaction configuration, 105 photons/pulse total photons were obtained (maximum). Transverse profiles of x-ray intensity and energy were measured by an x-ray CCD camera. These experiment profiles agreed with the analytical results. Imaging using this x-ray source was demonstrated as an application. X-ray images for some objects were taken with various lengths between the objects and the camera. As a result, the refraction contrast images were observed with 17keV x-rays.

12

Lipp, Vladimir, Ichiro Inoue, and Beata Ziaja. "Advantages of Using Hard X-ray Photons for Ultrafast Diffraction Measurements." Photonics 10, no. 8 (August 18, 2023): 948. http://dx.doi.org/10.3390/photonics10080948.

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We present a comparative theoretical study of silicon crystals irradiated with X-ray free-electron laser pulses, using hard X-ray photons of various energies. Simulations are performed with our in-house hybrid code XTANT based on Monte Carlo, Tight Binding and Molecular Dynamics simulation techniques. By comparing the strength of the coherently scattered signal and the corresponding electronic radiation damage for three X-ray photon energies available at the SACLA free-electron laser facility, we conclude that it would be beneficial to use higher photon energies for “diffraction-before-destruction” experiments.

13

Bencheikh, Mohamed, Abdelmajid Maghnouj, Jaouad Tajmouati, Abdessamad Didi, and Abdesslam Lamrabet. "Detailed Monte Carlo analysis of the secondary photons coming out of the therapeutic X-ray beam of linear accelerator." Polish Journal of Medical Physics and Engineering 27, no. 2 (June 1, 2021): 151–56. http://dx.doi.org/10.2478/pjmpe-2021-0018.

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Abstract External photon beam radiotherapy is often used in tumor treatment. The photons are generated from the target which had stricken by the primary electron beam (incident particles). The photon beam contains the primary photons coming directly from the target and secondary photons coming from the photon interactions with head component materials (scattered photons). Altogether is thereafter used in radiotherapy treatment. This Monte Carlo study aims to investigate and evaluate the secondary radiations (photons) in terms of fluence, energy fluence, spectral distribution, mean energy and angular spread distribution. The secondary photons, which contributed in radiotherapy treatment, are examined and evaluated in number (fluence) and energy. At the phantom surface, the secondary photons originated in the whole linac head are mainly coming from the primary collimator. In 0.45% of secondary photons coming from the whole linac head, the primary collimator contributes by 86% and they are more energetic. However, the flattening filter and the secondary collimator contribute together by less than 14% and their photons are less energetic and then can deteriorate the beam dosimetry quality. To improve the radiotherapy treatment quality, the number of photons of low energy should be as low as possible in the clinical beam. Our work can be a basic investigation to use in the improvement of linac head configuration and specially the beam modifiers.

14

Carvalho, A. M. G., D. H. C. Araújo, H. F. Canova, C. B. Rodella, D. H. Barrett, S. L. Cuffini, R. N. Costa, and R. S. Nunes. "X-ray powder diffraction at the XRD1 beamline at LNLS." Journal of Synchrotron Radiation 23, no. 6 (October 6, 2016): 1501–6. http://dx.doi.org/10.1107/s1600577516012686.

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Various upgrades have been completed at the XRD1 beamline at the Brazilian synchrotron light source (LNLS). The upgrades are comprehensive, with changes to both hardware and software, now allowing users of the beamline to conduct X-ray powder diffraction experiments with faster data acquisition times and improved quality. The main beamline parameters and the results obtained for different standards are presented, showing the beamline ability of performing high-quality experiments in transmission geometry. XRD1 operates in the 5.5–14 keV range and has a photon flux of 7.8 × 109 photons s−1(with 100 mA) at 12 keV, which is one of the typical working energies. At 8 keV (the other typical working energy) the photon flux at the sample position is 3.4 × 1010 photons s−1and the energy resolution ΔE/E= 3 × 10−4.

15

Lee, Eldred, Kaitlin M. Anagnost, Zhehui Wang, Michael R. James, Eric R. Fossum, and Jifeng Liu. "Monte Carlo Modeling and Design of Photon Energy Attenuation Layers for >10× Quantum Yield Enhancement in Si-Based Hard X-ray Detectors." Instruments 5, no. 2 (April 30, 2021): 17. http://dx.doi.org/10.3390/instruments5020017.

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High-energy (>20 keV) X-ray photon detection at high quantum yield, high spatial resolution, and short response time has long been an important area of study in physics. Scintillation is a prevalent method but limited in various ways. Directly detecting high-energy X-ray photons has been a challenge to this day, mainly due to low photon-to-photoelectron conversion efficiencies. Commercially available state-of-the-art Si direct detection products such as the Si charge-coupled device (CCD) are inefficient for >10 keV photons. Here, we present Monte Carlo simulation results and analyses to introduce a highly effective yet simple high-energy X-ray detection concept with significantly enhanced photon-to-electron conversion efficiencies composed of two layers: a top high-Z photon energy attenuation layer (PAL) and a bottom Si detector. We use the principle of photon energy down conversion, where high-energy X-ray photon energies are attenuated down to ≤10 keV via inelastic scattering suitable for efficient photoelectric absorption by Si. Our Monte Carlo simulation results demonstrate that a 10–30× increase in quantum yield can be achieved using PbTe PAL on Si, potentially advancing high-resolution, high-efficiency X-ray detection using PAL-enhanced Si CMOS image sensors.

16

Stoupin, Stanislav, Sergey Antipov, and Alexander M. Zaitsev. "High-dynamic-range transmission-mode detection of synchrotron radiation using X-ray excited optical luminescence in diamond." Journal of Synchrotron Radiation 27, no. 3 (March 13, 2020): 708–12. http://dx.doi.org/10.1107/s1600577520001174.

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Enhancement of X-ray excited optical luminescence in a 100 µm-thick diamond plate by introduction of defect states via electron beam irradiation and subsequent high-temperature annealing is demonstrated. The resulting X-ray transmission-mode scintillator features a linear response to incident photon flux in the range 7.6 × 108 to 1.26 × 1012 photons s−1 mm−2 for hard X-rays (15.9 keV) using exposure times from 0.01 to 5 s. These characteristics enable a real-time transmission-mode imaging of X-ray photon flux density without disruption of X-ray instrument operation.

17

Sorokin, Andrey A., Yilmaz Bican, Susanne Bonfigt, Maciej Brachmanski, Markus Braune, Ulf Fini Jastrow, Alexander Gottwald, Hendrik Kaser, Mathias Richter, and Kai Tiedtke. "An X-ray gas monitor for free-electron lasers." Journal of Synchrotron Radiation 26, no. 4 (June 12, 2019): 1092–100. http://dx.doi.org/10.1107/s1600577519005174.

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A novel X-ray gas monitor (XGM) has been developed which allows the measurement of absolute photon pulse energy and photon beam position at all existing and upcoming free-electron lasers (FELs) over a broad spectral range covering vacuum ultraviolet (VUV), extreme ultraviolet (EUV) and soft and hard X-rays. The XGM covers a wide dynamic range from spontaneous undulator radiation to FEL radiation and provides a temporal resolution of better than 200 ns. The XGM consists of two X-ray gas-monitor detectors (XGMDs) and two huge-aperture open electron multipliers (HAMPs). The HAMP enhances the detection efficiency of the XGM for low-intensity radiation down to 105 photons per pulse and for FEL radiation in the hard X-ray spectral range, while the XGMD operates in higher-intensity regimes. The relative standard uncertainty for measurements of the absolute photon pulse energy is well below 10%, and down to 1% for measurements of relative pulse-to-pulse intensity on pulses with more than 1010 photons per pulse. The accuracy of beam-position monitoring in the vertical and horizontal directions is of the order of 10 µm.

18

Wittry, D. B. "Focusing x rays for microprobe x-ray fluorescence analysis." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1730–31. http://dx.doi.org/10.1017/s042482010013328x.

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X-ray microprobes that use focused monochromatic x rays for fluorescence excitation have four significant advantages over electron microprobes that use focused electrons for direct excitation, namely: 1) less background radiation is produced, 2) there is little or no charging of insulating specimens, 3) less damage is caused to the specimen, and 4) the specimen often does not need a high vacuum environment. These advantages result from the difference in interaction of photon and electron beams with matter. In the first place, because the x-ray photon is uncharged, bremsstrahlung which is always obtained with electron bombardment, is not produced by photon bombardment; this results in higher signal/background ratio and can yield lower detection limits by a factor of about 10−2 of those obtained with electron microprobes. Also because the photon is uncharged, the only charging of insulating specimens is due to secondary effects. Second, x-ray photons preferentially excite inner shell electrons as is well known from the large increase in absorption coefficient when the photon energy exceeds the critical excitation energy; this results in less damage for a given number of characteristic x-rays produced in the specimen.

19

Jemian, P. R., and G. G. Long. "Silicon photodiode detector for small-angle X-ray scattering." Journal of Applied Crystallography 23, no. 5 (October 1, 1990): 430–32. http://dx.doi.org/10.1107/s0021889890005167.

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A photodiode X-ray detector was built to measure small-angle X-ray scattering (SAXS) at a synchrotron-radiation source in conjunction with a double-crystal diffractometer SAXS camera at photon energies between 5 and 11 keV. The photodiode detector response in this energy range is linear at photon counting rates up to 1012 photons s−1 and thus it was not necessary to attenuate the monochromatic X-ray beam with calibrated foils. SAXS data taken with a scintillation counter and the photodiode detector are compared, demonstrating marked improvement in counting statistics, rate of data acquisition and signal-to-noise ratio.

20

Hinger, V., A. al Haddad, R. Barten, A. Bergamaschi, M. Brückner, M. Carulla, S. Chiriotti-Alvarez, et al. "Advancing the JUNGFRAU detector toward low-energy X-ray applications." Journal of Instrumentation 17, no. 09 (September 1, 2022): C09027. http://dx.doi.org/10.1088/1748-0221/17/09/c09027.

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Abstract The charge-integrating hybrid silicon pixel detector JUNGFRAU has found widespread use at free-electron laser and synchrotron facilities. The detector was designed for use with hard X-rays; yet, because of its low noise, high dynamic range, position resolution, and scalable size, JUNGFRAU is of high interest for soft X-ray applications. We discuss improvements of the readout chip and alterations of the entrance window at the back of the sensor that facilitate low-energy X-ray detection. The first use case of the improved system at a low-energy beamline demonstrates single photon sensitivity down to 800 eV. At lower energies, the readout noise of the hybrid detector hinders the resolution of single photons. We propose to couple the JUNGFRAU readout chip with charge-multiplying low-gain avalanche diode (LGAD) sensors to resolve X-ray photons with a minimum energy of 250 eV.

21

OGINO, HARUYUKI, MENG DE, TOMOHIKO YAMAMOTO, FUMITO SAKAMOTO, KATSUHIRO DOBASHI, and MITSURU UESAKA. "LASER PULSE CIRCULATION SYSTEM FOR COMPACT MONOCHROMATIC TUNABLE HARD X-RAY SOURCE." International Journal of Modern Physics A 22, no. 23 (September 20, 2007): 4324–32. http://dx.doi.org/10.1142/s0217751x0703786x.

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We are construcing a laser electron Compton scattering monochromatic tunable hard X-ray source. It consists of the X-band (11.424 GHz) electron linear accelerator and Q-switch Nd : YAG laser. This work is a part of the JST (Japan Science and Technology Agency) project. The whole system is a part of the national project on the advanced compact medical accelerator development, hosted by NIRS (National Institute for Radiological Science). The University of Tokyo and KEK are working for the X-ray source. Main advantage of this X-ray source is monochromatic tunable hard X-rays (10-50keV) with the intensities of 108-109 photons/s. The table-top size X-ray source can generate dual energy monochromatic hard X-ray by turns and it takes about 40ms to chage the X-ray energy. It is calculated that the X-ray intensity is 107 photons/RF-pulse (108 photons/s in 10 pps) by the 35MeV electron and YAG laser (2J/pulse). The X-band beam line for the demonstration is under construction. We designed a laser pulse circulation system to increase the X-ray yield 10 times higer (up to 108 photons/RF-pulse, 109 photons/s). It can be proved that the laser total energy increases 10 times higher by the principle experiment with the lower energy laser (25mJ/pulse).

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Tan, Fang, Xiao Hui Zhang, Bin Zhu, Gang Li, Yu Chi Wu, Ming Hai Yu, Yue Yang, et al. "Compact Thomson Scattering Source Based on a Mixed Injection Assisted Laser Wakefield Accelerator." Laser and Particle Beams 2022 (September 17, 2022): 1–7. http://dx.doi.org/10.1155/2022/4132792.

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In order to establish a compact all-optical Thomson scattering source, experimental studies were conducted on the 45 TW Ti: sapphire laser facility. By including a steel wafer, mixed gas, and plasma mirror into a double-exit jet, several mechanisms, such as shock-assisted ionization injection, ionization injection, and driving laser reflection, were integrated into one source. So, the source of complexity was remarkably reduced. Electron bunches with central energy fluctuating from 90 to 160 MeV can be produced. Plasma mirrors were used to reflect the driving laser. The scattering of the reflected laser on the electron bunches led to the generation of X-ray photons. Through comparing the X-ray spots under different experimental conditions, it is confirmed that the X-ray photons are generated by Thomson scattering. For further application, the energy spectra and source size of the Thomson scattering source were measured. The unfolded spectrum contains a large amount of low-energy photons besides a peak near 67 keV. Through importing the electron energy spectrum into the Monte Carlo simulation code, the different contributions of the photons with small and large emitting angles can be used to explain the origin of the unfolded spectrum. The maximum photon energy extended to about 500 keV. The total photon production was 107/pulse. The FWHM source size was about 12 μm.

23

Liguori, Antonio, Rebecca Barten, Filippo Baruffaldi, Anna Bergamaschi, Giacomo Borghi, Maurizio Boscardin, Martin Brückner, et al. "Characterization of iLGADs using soft X-rays." Journal of Instrumentation 18, no. 12 (December 1, 2023): P12006. http://dx.doi.org/10.1088/1748-0221/18/12/p12006.

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Abstract Experiments at synchrotron radiation sources and X-ray Free-Electron Lasers in the soft X-ray energy range (250 eV–2 keV) stand to benefit from the adaptation of the hybrid silicon detector technology for low energy photons. Inverse Low Gain Avalanche Diode (iLGAD) sensors provide an internal gain, enhancing the signal-to-noise ratio and allowing single photon detection below 1 keV using hybrid detectors. In addition, an optimization of the entrance window of these sensors enhances their quantum efficiency (QE). In this work, the QE and the gain of a batch of different iLGAD diodes with optimized entrance windows were characterized using soft X-rays at the Surface/Interface:Microscopy beamline of the Swiss Light Source synchrotron. Above 250 eV, the QE is larger than 55% for all sensor variations, while the charge collection efficiency is close to 100%. The average gain depends on the gain layer design of the iLGADs and increases with photon energy. A fitting procedure is introduced to extract the multiplication factor as a function of the absorption depth of X-ray photons inside the sensors. In particular, the multiplication factors for electron- and hole-triggered avalanches are estimated, corresponding to photon absorption beyond or before the gain layer, respectively.

24

Jirsa, J., J. Gecnuk, Z. Janoska, J. Jakovenko, V. Kafka, M. Marcisovsky, M. Marcisovska, P. Stanek, L. Tomasek, and P. Vancura. "Monte-Carlo simulation of charge sharing in 2 mm thick pixelated CdTe sensor." Journal of Instrumentation 18, no. 02 (February 1, 2023): C02033. http://dx.doi.org/10.1088/1748-0221/18/02/c02033.

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Abstract Precise physical models of sensors are essential for developing high precision pixelated detectors. Advanced technologies allowed pixel electronics to be integrated in tens of micrometers pixel pitch. Such fine pixelated detectors suffer from charge sharing effect and, in high-Z materials, also from fluorescent photons traversing one or more pixels. This work presents a Monte-Carlo model of a 2 mm thick 70 μm pitch pixelated CdTe sensor designed for simulation of the absorption of X-ray photons from monochromatic X-ray photon beams. Charge diffusion across a pixel matrix was computed using a drift-diffusion model for each photon generating free electron-hole pairs. Based on the simulation outcome, we estimated the dependence of cluster size on photon energy and total charge distribution between neighboring pixels.

25

Metzger, T. H. "APPLIED PHYSICS: Squeezing X-ray Photons." Science 297, no. 5579 (July 12, 2002): 205–6. http://dx.doi.org/10.1126/science.1073847.

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26

Terada, Yasuko, Shino Homma-Takeda, Akihisa Takeuchi, and Yoshio Suzuki. "High-Energy X-Ray Microprobe System with Submicron Resolution for X-Ray Fluorescence Analysis of Uranium in Biological Specimens." X-Ray Optics and Instrumentation 2010 (July 5, 2010): 1–5. http://dx.doi.org/10.1155/2010/317909.

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Total-external-reflection Kirkpatrick-Baez mirror optics for high-energy X-rays have been applied to the X-ray microprobe at beamline 37XU of SPring-8. A focused beam size of 1.0 μm (V)×0.83 μm (H) has been achieved at an X-ray energy of 30 keV, and a total photon flux of the focused beam was about 5×109 photons/s. Micro-X-ray fluorescence (μ-XRF) analysis of the uranium distribution in rat kidneys has been performed with the mirror-focused beam. The sensitivity of uranium was evaluated from the XRF intensity of thin standard samples, and the minimum detection limit was estimated at 10 μg/g. The high-spatial-resolution analysis revealed that uranium was concentrated in the epithelium of the proximal tubules in the inner cortex. The maximum concentration of uranium in the tubule was estimated to be 503 μg/g using a semiquantitative evaluation.

27

Tripathi, Prakash, and Gulab Chand Dewangan. "Thermal Comptonization in a Changing Corona in the Changing-look Active Galaxy NGC 1566." Astrophysical Journal 930, no. 2 (May 1, 2022): 117. http://dx.doi.org/10.3847/1538-4357/ac610f.

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Abstract We present broadband UV/X-ray spectral variability of the changing-look active galactic nucleus (AGN) NGC 1566, based on simultaneous near-ultraviolet and X-ray observations performed by the XMM-Newton, Swift, and NuSTAR satellites at five different epochs during the declining phase of the 2018 outburst. We found that the accretion disk, soft X-ray excess, and X-ray power-law components were extremely variable. Additionally, the X-ray power-law flux was correlated with both the soft excess plus disk and the pure disk fluxes. Our finding shows that at high-flux levels the soft X-ray excess and the disk emission both provided the seed photons for thermal Comptonization in the hot corona, whereas at low-flux levels, where the soft excess was absent, the pure disk emission alone provided the seed photons. The X-ray power-law photon index was only weakly variable (ΔΓhot ≤ 0.06), and it was not well correlated with the X-ray flux over the declining timescale. On the other hand, we found that the electron temperature of the corona increased from ∼22 to ∼200 keV with the decreasing numbers of seed photons from 2018 June to 2019 August. At the same time, the optical depth of the corona decreased from τ hot ∼ 4 to ∼0.7, and the scattering fraction increased from ∼1% to ∼10%. These changes suggest structural changes in the hot corona, such as it was growing in size and becoming hotter with the decreasing accretion rate during the declining phase. The AGN is most likely evolving with a decreasing accretion rate toward a state similar to the low/hard state of black hole X-ray binaries.

28

Flaccomio, E., J. F. Albacete-Colombo, J. J. Drake, M. G. Guarcello, V. Kashyap, N. J. Wright, K. Briggs, B. Ercolano, M. McCollough, and S. Sciortino. "X-Ray Spectral Characterization of the Young Cygnus OB2 Population." Astrophysical Journal Supplement Series 269, no. 1 (October 25, 2023): 12. http://dx.doi.org/10.3847/1538-4365/acdd66.

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Abstract We analyze the X-ray spectra of the ∼8000 sources detected in the Cygnus OB2 Chandra Legacy Survey (this focus issue), with the goals of characterizing the coronal plasma of the young low-mass stars in the region and estimating their intrinsic X-ray luminosities. We adopt two different strategies for X-ray sources for which more or less than 20 photons were detected. For the brighter sample we fit the spectra with absorbed isothermal models. In order to limit uncertainties, for most of the fainter Cygnus OB2 members in this sample we constrain the spectral parameters to characteristic ranges defined from the brightest stars. For X-ray sources with <20 net photons we adopt a conversion factor from detected photon flux to intrinsic flux. This was defined, building on the results for the previous sample, as a function of the 20% quantile of the detected photon energy distributions, which we prove to also correlate well with extinction. We then use the X-ray extinction from the spectral fits to constrain the ratio between optical and X-ray extinction toward Cyg OB2, finding it consistent with standard “Galactic” values, when properly accounting for systematics. Finally, we exploit the large number of sources to constrain the average coronal abundances of several elements, through two different ensemble analyses of the X-ray spectra of low-mass Cyg OB2 members. We find the pattern of abundances to be largely consistent with that derived for the young stellar coronae in the Orion Nebula Cluster.

29

Durbin, Stephen M. "Proposal for entangled x-ray beams." Journal of Applied Physics 131, no. 22 (June 14, 2022): 224401. http://dx.doi.org/10.1063/5.0091947.

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A promising approach for direct detection of quantum entanglement in solid state materials is probing with entangled particles. X-rays are ideal for characterization of many materials but have not been generated as entangled pairs in useful numbers, even at the most powerful synchrotron sources. This proposal describes how x-rays in fully entangled N00N states (with N = 2) can be produced by applying Hong-Ou-Mandel interferometry at an x-ray synchrotron source. The technical requirements for indistinguishable photons, x-ray beamsplitters, and interferometer design are met with existing resources. The entangled x-ray biphotons can be filtered from the unavoidable single photon background by simple diffraction from an analyzer crystal, resulting in intense beams suitable for characterizing quantum materials.

30

Plavin, A. V., R. A. Burenin, Y. Y. Kovalev, A. A. Lutovinov, A. A. Starobinsky, S. V. Troitsky, and E. I. Zakharov. "Hard X-ray emission from blazars associated with high-energy neutrinos." Journal of Cosmology and Astroparticle Physics 2024, no. 05 (May 1, 2024): 133. http://dx.doi.org/10.1088/1475-7516/2024/05/133.

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Abstract Bright blazars were found to be prominent neutrino sources, and a number of IceCube events were associated with them. Evaluating high-energy photon emission of such blazars is crucial for better understanding of the processes and regions where neutrinos are produced. Here, we focus on hard X-ray emission observed by the SRG/ART-XC telescope, by the Swift/BAT imager, and by the INTEGRAL/IBIS telescope. Their energy range ≳10 keV is well-suited for probing photons that potentially participate in neutrino production by interacting with ultrarelativistic protons. We find that neutrino-associated blazars tend to demonstrate remarkably strong X-ray emission compared to other VLBI blazars in the sky. Both neutrinos and hard X-rays are found to come from blazars at cosmological distances z ∼ 1, and are boosted by relativistic beaming that makes it possible to detect them on Earth. Our results suggest that neutrinos are produced within compact blazar jets, with target X-ray photons emitted from accelerated jet regions.

31

Yamamoto, Seiichi, Tomohiro Yamashita, Yusuke Kobashi, Takuya Yabe, Takashi Akagi, Mitsutaka Yamaguchi, Naoki Kawachi, et al. "Simultaneous imaging of prompt gamma photons and prompt X-rays during irradiation of proton beams to human torso phantom at clinical dose level." Journal of Instrumentation 18, no. 07 (July 1, 2023): P07046. http://dx.doi.org/10.1088/1748-0221/18/07/p07046.

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Abstract Although both prompt gamma photon and prompt X-ray imaging are promising methods for observing a beam shape and estimating the range of the beam from outside a subject, the images using these two methods have not been compared under realistic conditions such as in a human torso phantom. To clarify the imaging capability of prompt gamma photon and prompt X-ray imaging, simultaneous imaging with these methods was conducted during irradiation by proton beams to a human torso phantom at clinical dose level. After a human torso phantom was set on the bed of a proton therapy system, proton pencil beams of three different energies at clinical dose level and a patient planning beam for prostate cancer were used to irradiate the phantom. Prompt gamma photons and prompt X-rays emitted from the phantom were simultaneously imaged by a developed gamma camera and an X-ray camera during irradiation with proton beams to the human torso phantom. For all of the tested beams, we could obtain the beam shapes of prompt gamma photons and prompt X-rays images. The ranges could be estimated within a difference of 11 mm and 14 mm from the calculated dose for prompt gamma photon and prompt X-ray images, respectively. For both types of images, time sequential images and time count rate curves could be derived. We could clarify the imaging capabilities of prompt gamma photons and prompt X-rays were different by the simultaneous imaging during proton irradiation to a human torso phantom. Although both methods had advantages and disadvantages, we confirmed that both methods are promising for beam imaging in a torso phantom and also for future clinical use in proton therapy.

32

Dong, Aijun, Chang Liu, Qijun Zhi, Ziyi You, Qibin Sun, and Bowen Du. "Spectral and Timing Properties of H 1743-322 in the “Faint” 2005 Normal Outburst." Universe 8, no. 5 (May 6, 2022): 273. http://dx.doi.org/10.3390/universe8050273.

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H 1743-322 is a well-known black hole X-ray binary (BH XRBs) that has been observed in several outbursts over the past. In this work, we have performed the spectral and timing analysis of H 1743-322 during the “faint” 2005 outburst for the first time with the RXTE/PCA data. In this outburst, the spectral and timing parameters (e.g., Tin, Γ, Rin, rms and QPOs, etc.) presented an obvious change and a q-like pattern was found in the Hardness Intensity Diagram (HID), which often named as the hysteresis effect of BH XRBs. The radius of the innermost stable circular orbit was constrained as RISCO∼3.50 Rg, which predicts that H 1743-322 is a lower-spin black hole. We further explored the correlation between timing and spectral properties. The relation of photon index Γ and X-ray flux, F3–25keV, presented a transition between negative and positive correlation when the X-ray luminosity, L3–25keV, is above and below a critical X-ray luminosity, LX,crit≃2.55×10−3 LEdd, which can be well explained by the Shakura-Sunyaev disk–corona model (SSD-corona) and advection-dominated accretion flow (ADAF). We also found the tight linear, negative correlation between photon index Γ and the total fractional rms. Since the amount of soft photons from the accretion disk seems invariable, an increase of the number of soft photons will dilute the variability from the harder photons. Therefore, the softer the X-ray spectra will result in the smaller total fractional rms. The above results suggested that the 2005 outburst of H 1743-322 was a normal outburst and H 1743-322 represented similar properties with other black hole X-ray binaries.

33

Galea, C. A., C. P. S. Swanson, S. A. Cohen, and S. J. Thomas. "Use of a Mylar filter to eliminate vacuum ultraviolet pulse pileup in low-energy x-ray measurements." Review of Scientific Instruments 93, no. 9 (September 1, 2022): 093531. http://dx.doi.org/10.1063/5.0101712.

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We describe a method to reduce vacuum ultraviolet (VUV) pulse pileup (PPU) in x-ray pulse-height Silicon Drift Detector (SDD) signals. An Amptek FAST SDD, with C1 (Si3N4) window, measures bremsstrahlung emitted from PFRC-2 plasma to extract the electron temperature (T e) and density (n e). The C1 window has low transmissivity for photons with energy below 200 eV though will transmit some VUV and soft x-ray photons, which PFRC-2 plasmas abundantly emit. Multi-VUV-photon PPU contaminates the interpretation of x rays with energy [Formula: see text] 100 eV, particularly in a low-energy exponential tail. The predicted low transmissivity of ∼1 μm thick Mylar [polyethylene terephthalate (PET)] to photons of energy [Formula: see text] eV led to the selection of Mylar as the candidate filter to reduce VUV PPU. Experiments were conducted on an x-ray tube with a graphite target and on a quasi-Maxwellian tenuous plasma (n e ∼ 109 cm−3) with effective temperatures reaching 1500 eV. A Mylar filter thickness of 850 nm is consistent with the results. The Mylar-filter-equipped SDD was then used on the PFRC-2 plasma, showing a substantial reduction in the low-energy x-ray signal, supporting our hypothesis of the importance of VUV PPU. We describe the modeling and experiments performed to characterize the effect of the Mylar filter on SDD measurements.

34

Modi, Mohammed H., P. Yadav, R. K. Gupta, and Shruti Gupta. "Design of a soft x-ray emission spectrometer setup for soft x-ray reflectivity beamline of Indus-2." Journal of Physics: Conference Series 2380, no. 1 (December 1, 2022): 012049. http://dx.doi.org/10.1088/1742-6596/2380/1/012049.

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Abstract A soft x-ray reflectivity beamline is operational on Indus-2 synchrotron source since 2016 for reflectivity, transmission and absorption measurements in 100-1500 eV photon energy range. To perform spectroscopic experiments in 60-1000 eV spectral range a soft x-ray emission spectrometer (SXES) is designed which will serve as an additional experimental station on the beamline. The SXES setup is designed using aberration corrected varied line spacing flat filed gratings which will disperse soft x-ray emission photons on a CCD screen. Gratings of nominal line density of 1200 l/mm and 2400 l/mm are used to cover 60-250 eV and 120-1000 eV energy range respectively.

35

Siddons, D. P., C. Riekel, and J. B. Hastings. "Small-angle X-ray scattering at high energies." Journal of Applied Crystallography 23, no. 5 (October 1, 1990): 401–5. http://dx.doi.org/10.1107/s0021889890005787.

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Initial tests are described of a high-resolution small-angle X-ray scattering apparatus adapted for operation at high photon energies. The energy chosen was 50 keV, and was limited by the available source. All orders of scattering out to the seventh were observed from a sample of 0.9 μm diameter latex spheres in a 4 h experiment. Phase separation in a binary Al–Li alloy was studied by the observation of spherical Al3Li precipitates. This demonstrates that the use of perfect-crystal collimators and analyzers yields a resolution function which does not depend on photon energy. New sources of high-energy photons will make such an apparatus invaluable for the study of highly absorbing samples, or samples in difficult environments such as ovens or high-pressure cells.

36

Krishnananda, Santosh Mirji, S. Ramesh Babu, K. M. Niranjana, and N. M. Badiger. "Measurement of anomalous scattering factors of tin using characteristic X-ray photons." Canadian Journal of Physics 93, no. 10 (October 2015): 1112–16. http://dx.doi.org/10.1139/cjp-2014-0684.

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The imaginary and real parts of anomalous scattering factors of Sn atoms around the K shell binding energy are measured using K and L X-ray photons. Gamma photons of energy 59.54 keV from an Am-241 radioactive source are used to excite K and L X-ray photons of various energies. By measuring the intensities of incident and transmitted X-ray photons in Sn foil with a good geometry arrangement, the K shell photoelectric cross sections are determined around the K shell binding energy of Sn. The real and imaginary parts of anomalous scattering factors of Sn are determined from K shell photoelectric cross section values. Experimentally determined form factors are compared with the theoretical prediction and experimental data obtained with synchrotron source.

37

Zhang, K., G. Rosenbaum, and G. Bunker. "Energy-Resolving X-ray Fluorescence Detection Using Synthetic Multilayers." Journal of Synchrotron Radiation 5, no. 4 (July 1, 1998): 1227–34. http://dx.doi.org/10.1107/s0909049597019535.

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The potential of synthetic multilayers for energy-resolving the X-ray fluorescence in X-ray absorption fine structure (XAFS) experiments is discussed. Two detection systems, one using curved multilayers and the other using graded multilayers to select X-ray fluorescence photons, have been designed to cover a wide energy range with a usefully large solid angle. Such a detector will be more advantageous than the barrel-like crystal-array detector because of the unique properties of synthetic multilayers, such as larger horizontal acceptance angles and bandwidth. In addition, the detector should be much simpler to construct and readily accommodates energy changes, especially the detector using graded multilayers. Comparison of the multilayer array detector with conventional detectors, such as ionization chambers and conventional 13-element Ge detectors, shows that the proposed system will be superior, particularly with the increased photon fluxes available from insertion devices and with decreased sample concentration, since this detection system eliminates the `bad' photons before they enter any X-ray detector. Consequently, the X-ray detector proper for this system does not suffer from the incident-count-rate bottleneck common to current X-ray fluorescence detectors with energy resolution by signal processing. Thus, this new fluorescence detection system will provide tremendous opportunities for XAFS measurements on dilute systems, such as biological systems, at third-generation synchrotron sources.

38

Reig, Pablo, and Nikolaos D. Kylafis. "Inclination effects on the X-ray emission of Galactic black-hole binaries." Astronomy & Astrophysics 625 (May 2019): A90. http://dx.doi.org/10.1051/0004-6361/201935070.

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Context. Galactic black-hole X-ray binaries (BHBs) emit a compact, optically thick, mildly relativistic radio jet when they are in hard and hard-intermediate states. In these states, BHBs exhibit a correlation between the time lag of hard with respect to softer photons and the photon index of the power law component that characterizes the X-ray spectral continuum above ∼10 keV. The correlation, however, shows large scatter. In recent years, several works have brought to light the importance of taking into account the inclination of the systems to understand the X-ray and radio phenomenology of BHBs. Aims. Our objective is to investigate the role that the inclination plays on the correlation between the time lag and photon index. Methods. We obtained RXTE energy spectra and light curves of a sample of BHBs with different inclination angles. We computed the photon index and the time lag between hard and soft photons and performed a correlation and linear regression analysis of the two variables. We also computed energy spectra and light curves of BHBs using the Monte Carlo technique that reproduces the process of Comptonization in the jet. We account for the inclination effects by recording the photons that escape from the jet at different angles. From the simulated light curves and spectra we obtained model-dependent photon index and time lags, which we compared with those obtained from the real data. Results. We find that the correlation between the time lag and photon index is tight in low-inclination systems and becomes weaker in high-inclination systems. The amplitude of the lags is also larger at low- and intermediate-inclination angles than at high inclination. We also find that the photon index and time lag, obtained from the simulated spectra and light curves, also follow different relationships for different inclination angle ranges. Our jet model reproduces the observations remarkably well. The same set of models that reproduces the correlation for the low-inclination systems, also accounts for the correlation for intermediate- and high-inclination systems fairly well. Conclusions. The large dispersion observed in the time lag – photon index correlation in BHBs can naturally be explained as an inclination effect. Comptonization in the jet explains the steeper dependence of the lags on the photon index in low- and intermediate-inclination systems than in high-inclination systems.

39

Osgood, R. M., Y. Ait-El-Aoud, K. Bullion, S. Dinneen, R. Kingsborough, M. Rothschild, and S. Kooi. "Fabry-Perot interference pattern scattered by a sub-monolayer array of nanoparticles." Materials Research Express 9, no. 1 (January 1, 2022): 016202. http://dx.doi.org/10.1088/2053-1591/ac487c.

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Abstract Understanding scattering of visible and infrared photons from nanomaterials and nanostructured materials is increasingly important for imaging, thermal management, and detection, and has implications for other parts of the electromagnetic spectrum (e.g., x-ray scattering and radar). New, interesting reports of photon scattering as a diagnostic probe, from inelastic x-ray scattering and interference to ‘nano-FTIR’ microscopy using infrared photons, have been published and are under active investigation in laboratories around the world. Here, we report, for the first time to our best knowledge, the experimental discovery of a Fabry–Perot interference pattern that is scattered by the sub-monolayer array of plasmonic Ag nanoparticles, and confirm it analytically and with rigorous numerical FDTD simulations.

40

Grybos, P., R. Kleczek, P. Kmon, A. Krzyzanowska, P. Otfinowski, R. Szczygiel, and M. Zoladz. "Pixel readout IC for CdTe detectors operating in single photon counting mode with interpixel communication." Journal of Instrumentation 17, no. 01 (January 1, 2022): C01036. http://dx.doi.org/10.1088/1748-0221/17/01/c01036.

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Abstract This paper presents a readout integrated circuit (IC) of pixel architecture called MPIX (Multithreshold PIXels), designed for CdTe pixel detectors used in X-ray imaging applications. The MPIX IC area is 9.6 mm × 20.3 mm and it is designed in a CMOS 130 nm process. The IC core is a matrix of 96 × 192 square-shaped pixels of 100 µm pitch. Each pixel contains a fast analog front-end followed by four independently working discriminators and four 12-bit ripple counters. Such pixel architecture allows photon processing one by one and selecting the X-ray photons according to their energy (X-ray colour imaging). To fit the different range of applications the MPIX IC has 8 possible different gain settings, and it can process the X-ray photons of energy up to 154 keV. The MPIX chip is bump-bonded to the CdTe 1.5 mm thick pixel sensor with a pixel pitch of 100 µm. To deal with the charge sharing effect coming from a thick semiconductor pixel sensor, multithreshold pattern recognition algorithm is implemented in the readout IC. The implemented algorithm operates both in the analog domain (to recover the total charge spread between neighboring pixels, when a single X-ray photon hits the border of the pixel) and in the digital domain (to allocate a hit position to a single pixel).

41

Щагин, А. В., В. И. Волков, В. С. Мирошник, А. С. Кубанкин та А. Н. Олейник. "Свойства керамического пироэлектрического генератора рентгеновского излучения в зависимости от давления остаточного газа". Письма в журнал технической физики 44, № 2 (2018): 18. http://dx.doi.org/10.21883/pjtf.2018.02.45460.16978.

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AbstractThe properties of X-ray emission from a pyroelectric accelerator based on ferroelectric ceramics have been experimentally studied, including the maximum energy of X-ray photons and their maximum yield generated by accelerated electrons at various pressures of residual gas in the generator chamber. The maximum X-ray yield and maximum energy of X-ray photons and accelerated electrons have been observed at a residual-gas pressure of around several millitorr.

42

Klysubun, Wantana, Pinit Kidkhunthod, Pongjakr Tarawarakarn, Panidtha Sombunchoo, Chanapa Kongmark, Sukit Limpijumnong, Saroj Rujirawat, Rattikorn Yimnirun, Gamolwan Tumcharern, and Kajornsak Faungnawakij. "SUT-NANOTEC-SLRI beamline for X-ray absorption spectroscopy." Journal of Synchrotron Radiation 24, no. 3 (April 4, 2017): 707–16. http://dx.doi.org/10.1107/s1600577517004830.

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The SUT-NANOTEC-SLRI beamline was constructed in 2012 as the flagship of the SUT-NANOTEC-SLRI Joint Research Facility for Synchrotron Utilization, co-established by Suranaree University of Technology (SUT), National Nanotechnology Center (NANOTEC) and Synchrotron Light Research Institute (SLRI). It is an intermediate-energy X-ray absorption spectroscopy (XAS) beamline at SLRI. The beamline delivers an unfocused monochromatic X-ray beam of tunable photon energy (1.25–10 keV). The maximum normal incident beam size is 13 mm (width) × 1 mm (height) with a photon flux of 3 × 108to 2 × 1010 photons s−1(100 mA)−1varying across photon energies. Details of the beamline and XAS instrumentation are described. To demonstrate the beamline performance,K-edge XANES spectra of MgO, Al2O3, S8, FeS, FeSO4, Cu, Cu2O and CuO, and EXAFS spectra of Cu and CuO are presented.

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Chaulagain, U., M. Lamač, M. Raclavský, K. P. Khakurel, Kavya H. Rao, K. Ta-Phuoc, S. V. Bulanov, and J. Nejdl. "ELI Gammatron Beamline: A Dawn of Ultrafast Hard X-ray Science." Photonics 9, no. 11 (November 11, 2022): 853. http://dx.doi.org/10.3390/photonics9110853.

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The realization of compact X-ray sources is one of the most intriguing applications of laser-plasma based electron acceleration. These sources based on the oscillation of short micron-sized bunches of relativistic electrons provide femtosecond X-ray pulses that are collimated, bright, and partially coherent. The state-of-the-art laser plasma X-ray sources can provide photon flux of over 1011 photons/shot. The photon flux can further be enhanced with the availability of high repetition rate, high-power lasers, providing capacities complementary to the large scale facilities such as synchrotrons and X-ray free-electron lasers. Even though the optimization of such sources has been underway for the last two decades, their applications in material and biological sciences are still emerging, which entail the necessity of a user-oriented X-ray beamlines. Based on this concept, a high-power-laser-based user-oriented X-ray source is being developed at ELI Beamlines. This article reports on the ELI Gammatron beamline and presents an overview of the research accessible with the ultrashort hard X-ray pulses at the ELI Gammatron beamline.

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Jones, K. W., B. M. Gordon, G. Schidlovsky, P. Spanne, Xue Dejun, and A. J. Saubermann. "Biomedical elemental analysis and imaging using synchrotron x-ray microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 180–81. http://dx.doi.org/10.1017/s0424820100134491.

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The application of synchrotron x-ray microscopy to biomedical research is currently in progress at the Brookhaven National Synchrotron Light Source. The current status of the x-ray microscope (XRM) from a technical standpoint is reviewed. Some of the items considered are photon flux, spatial resolution, quantitation, minimum detection limits, and beam-induced specimen damage. Examples of measurements made with the XRM are then given.The XRM has generally used continuous energy bending magnet radiation as the x-ray source. A mechanical collimator placed close to the specimen is used to define x-ray beams of 3-5/μm size. The size of the beam can be adjusted to some extent by tilting the collimator with respect to the beam direction. The photon flux is maximized by locating the XRM as close to the x-ray source as possible (9 m). Flux values of about 3 × 108 photons/(s-μm2) are obtained with a 100mA current of electrons in the storage ring.

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Kisaka, Shota, and Shuta J. Tanaka. "Luminosity of synchrotron radiation from outer magnetosphere of pulsars." Proceedings of the International Astronomical Union 13, S337 (September 2017): 354–55. http://dx.doi.org/10.1017/s1743921317008432.

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AbstractWe calculate the luminosity of the synchrotron radiation from the vicinity of the light cylinder. We find that even if the thermal emission from the entire surface is included as the seed photon, the γ-ray to X-ray flux ratio for young pulsars is significantly higher than the observations. For these pulsars, most of γ-ray photons may be absorbed in the magnetosphere.

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Szymonowicz, Klaudia, Adam Krysztofiak, Jansje van der Linden, Ajvar Kern, Simon Deycmar, Sebastian Oeck, Anthony Squire, et al. "Proton Irradiation Increases the Necessity for Homologous Recombination Repair Along with the Indispensability of Non-Homologous End Joining." Cells 9, no. 4 (April 5, 2020): 889. http://dx.doi.org/10.3390/cells9040889.

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Technical improvements in clinical radiotherapy for maximizing cytotoxicity to the tumor while limiting negative impact on co-irradiated healthy tissues include the increasing use of particle therapy (e.g., proton therapy) worldwide. Yet potential differences in the biology of DNA damage induction and repair between irradiation with X-ray photons and protons remain elusive. We compared the differences in DNA double strand break (DSB) repair and survival of cells compromised in non-homologous end joining (NHEJ), homologous recombination repair (HRR) or both, after irradiation with an equal dose of X-ray photons, entrance plateau (EP) protons, and mid spread-out Bragg peak (SOBP) protons. We used super-resolution microscopy to investigate potential differences in spatial distribution of DNA damage foci upon irradiation. While DNA damage foci were equally distributed throughout the nucleus after X-ray photon irradiation, we observed more clustered DNA damage foci upon proton irradiation. Furthermore, deficiency in essential NHEJ proteins delayed DNA repair kinetics and sensitized cells to both, X-ray photon and proton irradiation, whereas deficiency in HRR proteins sensitized cells only to proton irradiation. We assume that NHEJ is indispensable for processing DNA DSB independent of the irradiation source, whereas the importance of HRR rises with increasing energy of applied irradiation.

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Pellegrini, Claudio. "The Next Generation of X-ray Sources." Reviews of Accelerator Science and Technology 03, no. 01 (January 2010): 185–202. http://dx.doi.org/10.1142/s1793626810000452.

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We discuss recent results on soft and hard X-ray free electron lasers (FELs) and how they can be used to design and optimize the next generation of these sources of high brightness, coherent photons, with femtosecond pulse duration, or very narrow linewidth. In particular, we consider the experimental and theoretical progress in the electron beam generation and manipulation. These results, when combined with the successful development of powerful simulation codes, can be used to design optimized, high intensity sources of coherent photons, and to reduce their size and cost.

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Zhu, Xing-Long, Min Chen, Su-Ming Weng, Tong-Pu Yu, Wei-Min Wang, Feng He, Zheng-Ming Sheng, Paul McKenna, Dino A. Jaroszynski та Jie Zhang. "Extremely brilliant GeV γ-rays from a two-stage laser-plasma accelerator". Science Advances 6, № 22 (травень 2020): eaaz7240. http://dx.doi.org/10.1126/sciadv.aaz7240.

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Recent developments in laser-wakefield accelerators have led to compact ultrashort X/γ-ray sources that can deliver peak brilliance comparable with conventional synchrotron sources. Such sources normally have low efficiencies and are limited to 107–8 photons/shot in the keV to MeV range. We present a novel scheme to efficiently produce collimated ultrabright γ-ray beams with photon energies tunable up to GeV by focusing a multi-petawatt laser pulse into a two-stage wakefield accelerator. This high-intensity laser enables efficient generation of a multi-GeV electron beam with a high density and tens-nC charge in the first stage. Subsequently, both the laser and electron beams enter into a higher-density plasma region in the second stage. Numerical simulations demonstrate that more than 1012 γ-ray photons/shot are produced with energy conversion efficiency above 10% for photons above 1 MeV, and the peak brilliance is above 1026 photons s−1 mm−2 mrad−2 per 0.1% bandwidth at 1 MeV. This offers new opportunities for both fundamental and applied research.

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Hatsui, Takaki, and Heinz Graafsma. "X-ray imaging detectors for synchrotron and XFEL sources." IUCrJ 2, no. 3 (April 10, 2015): 371–83. http://dx.doi.org/10.1107/s205225251500010x.

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Current trends for X-ray imaging detectors based on hybrid and monolithic detector technologies are reviewed. Hybrid detectors with photon-counting pixels have proven to be very powerful tools at synchrotrons. Recent developments continue to improve their performance, especially for higher spatial resolution at higher count rates with higher frame rates. Recent developments for X-ray free-electron laser (XFEL) experiments provide high-frame-rate integrating detectors with both high sensitivity and high peak signal. Similar performance improvements are sought in monolithic detectors. The monolithic approach also offers a lower noise floor, which is required for the detection of soft X-ray photons. The link between technology development and detector performance is described briefly in the context of potential future capabilities for X-ray imaging detectors.

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Feder, R., and V. Mayne-Banton. "X-Ray Contact Imaging: the Technique." Proceedings, annual meeting, Electron Microscopy Society of America 43 (August 1985): 596–99. http://dx.doi.org/10.1017/s0424820100119764.

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Until recently, instruments used to image small biological objects directly have involved the use of light microscopy or electron microscopy. Presently, the use of x-rays has emerged as another probe to investigate details in biological specimens. X-rays can be used either by using an x-ray “lens”, which will be discussed by others at this symposium or by a direct contact “print” of the object on a special emulsion. This latter method is what will be discussed in this paper.The object to be ‘photographed’ is prepared on a substrate and then placed in contact with a resist such as poly- methyl-methacrylate (PMMA). This polymer has the property that when it is exposed to x-rays and then placed in a solution of methyl isobutyl ketone (MIBK) it will 'develop’ depending on the number of x-ray photons absorbed in the PMMA. This three dimensional relief structure is actually a photon density map of the specimen.

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