Journal articles: 'Photon beam-position monitor'

1

Izumi, T., T. Nakajima, and T. Kurihama. "Photon beam position monitor." Review of Scientific Instruments 60, no. 7 (July 1989): 1951–52. http://dx.doi.org/10.1063/1.1140897.

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Ko, J., I. Y. Kim, C. Kim, D. T. Kim, J. Y. Huang, and S. Shin. "Analysis and control of the photon beam position at PLS-II." Journal of Synchrotron Radiation 23, no. 2 (February 18, 2016): 448–54. http://dx.doi.org/10.1107/s1600577516001338.

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At third-generation light sources, the photon beam position stability is a critical issue for user experiments. In general, photon beam position monitors are developed to detect the real photon beam position, and the position is controlled by a feedback system in order to maintain the reference photon beam position. At Pohang Light Source II, a photon beam position stability of less than 1 µm r.m.s. was achieved for a user service period in the beamline, where the photon beam position monitor is installed. Nevertheless, a detailed analysis of the photon beam position data was necessary in order to ensure the performance of the photon beam position monitor, since it can suffer from various unknown types of noise, such as background contamination due to upstream or downstream dipole radiation, and undulator gap dependence. This paper reports the results of a start-to-end study of the photon beam position stability and a singular value decomposition analysis to confirm the reliability of the photon beam position data.

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Mitsuhashi, T., A. Ueda, and T. Katsura. "High‐flux photon beam position monitor." Review of Scientific Instruments 63, no. 1 (January 1992): 534–37. http://dx.doi.org/10.1063/1.1142698.

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Johnson, E. D., and T. Oversluizen. "Compact high flux photon beam position monitor." Review of Scientific Instruments 60, no. 7 (July 1989): 1947–50. http://dx.doi.org/10.1063/1.1140896.

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Samadi, Nazanin, Bassey Bassey, Mercedes Martinson, George Belev, Les Dallin, Mark de Jong, and Dean Chapman. "A phase-space beam position monitor for synchrotron radiation." Journal of Synchrotron Radiation 22, no. 4 (June 25, 2015): 946–55. http://dx.doi.org/10.1107/s1600577515007390.

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The stability of the photon beam position on synchrotron beamlines is critical for most if not all synchrotron radiation experiments. The position of the beam at the experiment or optical element location is set by the position and angle of the electron beam source as it traverses the magnetic field of the bend-magnet or insertion device. Thus an ideal photon beam monitor would be able to simultaneously measure the photon beam's position and angle, and thus infer the electron beam's position in phase space. X-ray diffraction is commonly used to prepare monochromatic beams on X-ray beamlines usually in the form of a double-crystal monochromator. Diffraction couples the photon wavelength or energy to the incident angle on the lattice planes within the crystal. The beam from such a monochromator will contain a spread of energies due to the vertical divergence of the photon beam from the source. This range of energies can easily cover the absorption edge of a filter element such as iodine at 33.17 keV. A vertical profile measurement of the photon beam footprint with and without the filter can be used to determine the vertical centroid position and angle of the photon beam. In the measurements described here an imaging detector is used to measure these vertical profiles with an iodine filter that horizontally covers part of the monochromatic beam. The goal was to investigate the use of a combined monochromator, filter and detector as a phase-space beam position monitor. The system was tested for sensitivity to position and angle under a number of synchrotron operating conditions, such as normal operations and special operating modes where the photon beam is intentionally altered in position and angle at the source point. The results are comparable with other methods of beam position measurement and indicate that such a system is feasible in situations where part of the synchrotron beam can be used for the phase-space measurement.

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Kim, Changbum, Jong Chel Yoon, Seung-nam Kim, Myong-jin Kim, Hee Seob Kim, Chun Kil Ryu, Chae-soon Lee, et al. "Photon-beam-position-monitor in PLS Diagnostic Beamline." Journal of the Korean Physical Society 56, no. 6(1) (June 15, 2010): 1981–84. http://dx.doi.org/10.3938/jkps.56.1981.

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7

Cerino, John A., Thomas Rabedeau, and William Bowen. "Photon beam position monitor for SSRL Beamline 9." Review of Scientific Instruments 66, no. 2 (February 1995): 1646–47. http://dx.doi.org/10.1063/1.1145871.

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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.

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Kim, Changbum, Seunghwan Shin, Ilmoon Hwang, Byung-Joon Lee, Young-Do Joo, Taekyun Ha, Jong Chel Yoon, et al. "Correlation study of a beam-position monitor and a photon-beam-position monitor in the PLS-II." Journal of the Korean Physical Society 66, no. 2 (January 2015): 167–70. http://dx.doi.org/10.3938/jkps.66.167.

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10

Chen, J. R., T. S. Ueng, G. Y. Hsiung, T. F. Lin, C. T. Lee, S. L. Tsai, and S. L. Chang. "A synchrotron radiation beam-position monitor at the Taiwan Light Source." Journal of Synchrotron Radiation 5, no. 3 (May 1, 1998): 621–23. http://dx.doi.org/10.1107/s0909049597018207.

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A prototype photon-beam-position monitor has been designed, fabricated and tested at the Taiwan Light Source of the Synchrotron Radiation Research Center. Aluminium was chosen as the material of the blade electrodes due to its low atomic number and high thermal conductivity. The resolution of this photon-beam-position monitor was <±1 µm. The sensitivity of the blade electrode has been measured in situ. Results of measurements for bending-magnet light and undulator light with different gaps are described.

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Gu Liming, 顾黎明, 孙葆根 Sun Baogen, 卢平 Lu Ping, 杨永良 Yang Yongliang, 肖云云 Xiao Yunyun, 王季刚 Wang Jigang, and 程超才 Cheng Chaocai. "Staggered-blade photon beam position monitor at Hefei Light Source." High Power Laser and Particle Beams 24, no. 8 (2012): 1990–94. http://dx.doi.org/10.3788/hplpb20122408.1990.

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12

Yuh, Jih-Young, Shan-Wei Lin, Liang-Jen Huang, Hok-Sum Fung, Long-Life Lee, Yu-Joung Chen, Chiu-Ping Cheng, Yi-Ying Chin, and Hong-Ji Lin. "Upgrade of beamline BL08B at Taiwan Light Source from a photon-BPM to a double-grating SGM beamline." Journal of Synchrotron Radiation 22, no. 5 (August 8, 2015): 1312–18. http://dx.doi.org/10.1107/s1600577515014009.

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During the last 20 years, beamline BL08B has been upgraded step by step from a photon beam-position monitor (BPM) to a testing beamline and a single-grating beamline that enables experiments to record X-ray photo-emission spectra (XPS) and X-ray absorption spectra (XAS) for research in solar physics, organic semiconductor materials and spinel oxides, with soft X-ray photon energies in the range 300–1000 eV. Demands for photon energy to extend to the extreme ultraviolet region for applications in nano-fabrication and topological thin films are increasing. The basic spherical-grating monochromator beamline was again upgraded by adding a second grating that delivers photons of energy from 80 to 420 eV. Four end-stations were designed for experiments with XPS, XAS, interstellar photoprocess systems (IPS) and extreme-ultraviolet lithography (EUVL) in the scheduled beam time. The data from these experiments show a large count rate in core levels probed and excellent statistics on background normalization in theL-edge adsorption spectrum.

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13

Haga, K., T. Honda, M. Tadano, T. Obina, and T. Kasuga. "New beam-position monitor system for upgraded Photon Factory storage ring." Journal of Synchrotron Radiation 5, no. 3 (May 1, 1998): 624–26. http://dx.doi.org/10.1107/s0909049597014349.

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Accompanying the brilliance-upgrading project at the Photon Factory storage ring, the beam-position monitor (BPM) system has been renovated. The new system was designed to enable precise and fast measurements to correct the closed-orbit distortion (COD), as well as to feed back the orbit position during user runs. There are 42 BPMs newly installed, amounting to a total of 65 BPMs. All of the BPMs are calibrated on the test bench using a coaxially strung metallic wire. The measured electrical offsets are typically 200 µm in both directions, which is 1/2–1/3 of those of the old-type BPMs. In the signal-processing system, PIN diode switches are employed in order to improve reliability. In the fastest mode, this system is capable of measuring COD within about 10 ms; this fast acquisition will allow fast suppression of the beam movement for frequencies up to 50 Hz using a global feedback system.

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14

Chung, Y., and E. Kahana. "Performance of the beam position monitor for the Advanced Photon Source." Review of Scientific Instruments 67, no. 9 (September 1996): 3366–67. http://dx.doi.org/10.1063/1.1146860.

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15

He, Jun, Yanfeng Sui, Yong Li, Huizhou Ma, Yaoyao Du, Xujian Wang, Junhui Yue, and Jianshe Cao. "Beam Position Monitor Characterization for the High Energy Photon Source Synchrotron." Symmetry 15, no. 3 (March 6, 2023): 660. http://dx.doi.org/10.3390/sym15030660.

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Beam position monitor (BPM) characterization has been widely studied at the synchrotron. The characteristic impedance of a stripline BPM was designed using a simulation and measured using the time-domain reflectometer method. The mechanical and electrical parameters of the feedthroughs with the buttons used for the BPMs were measured. Special care was taken in the analysis of the consistency of the four channels of the BPM. The feedthroughs were sorted based on their capacitance values. This paper presents the characterization results of the feedthroughs and BPMs. The electro-mechanical offsets were measured using the Lambertson method, and the calibration coefficients were measured using a stretched wire. The BPM differences introduced during mass production were determined by a statistical analysis of the measurement results.

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16

Honda, T., M. Katoh, T. Mitsuhashi, A. Ueda, M. Tadano, and Y. Kobayashi. "Single-pass BPM system of the Photon Factory storage ring." Journal of Synchrotron Radiation 5, no. 3 (May 1, 1998): 618–20. http://dx.doi.org/10.1107/s0909049597015094.

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At the 2.5 GeV ring of the Photon Factory, a single-pass beam-position monitor (BPM) system is being prepared for the storage ring and the beam transport line. In the storage ring, the injected beam position during the first several turns can be measured with a single injection pulse. The BPM system has an adequate performance, useful for the commissioning of the new low-emittance lattice. Several stripline BPMs are being installed in the beam transport line. The continuous monitoring of the orbit in the beam transport line will be useful for the stabilization of the injection energy as well as the injection beam orbit.

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Shu, Deming, and Tuncer Kuzay. "Smart x‐ray beam position monitor system for the Advanced Photon Source." Review of Scientific Instruments 67, no. 9 (September 1996): 3367. http://dx.doi.org/10.1063/1.1147367.

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18

Huang, J. Y., and I. S. Ko. "Spatio-temporal measurement of beam properties in the PLS diagnostic beamline." Journal of Synchrotron Radiation 5, no. 3 (May 1, 1998): 642–44. http://dx.doi.org/10.1107/s090904959702013x.

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A diagnostic beamline is being constructed in the PLS storage ring for measurement of electron- and photon-beam properties. It consists of two 1:1 imaging systems: a visible-light imaging system and a soft X-ray imaging system. In the visible-light imaging system, the transverse beam size and beam position are measured with various detectors: a CCD camera, two photodiode arrays and a photon-beam position monitor. Longitudinal bunch structure is also investigated with a fast photodiode detector and a picosecond streak camera. On the other hand, the soft X-ray imaging system is under construction to measure beam sizes with negligible diffraction-limited error. The X-ray image optics consist of a flat cooled mirror and two spherical focusing mirrors.

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Shu, Deming, Tuncer M. Kuzay, Yue Fang, Juan Barraza, and Tim Cundiff. "Synthetic diamond-based position-sensitive photoconductive detector development for the Advanced Photon Source." Journal of Synchrotron Radiation 5, no. 3 (May 1, 1998): 636–38. http://dx.doi.org/10.1107/s0909049597019778.

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A novel X-ray beam-position detection device that we call a position-sensitive photoconductive detector (PSPCD) is designed to have synthetic diamond as its substrate material. We proved that it is feasible to use synthetic diamond to make a hard X-ray position-sensitive detector based on the photoconductivity principle and that it acts as a solid-state ion chamber. Experiments on different PSPCD samples using synthetic diamond with a high-heat-flux white undulator beam, as well as with monochromatic hard X-ray beams, have been performed at the Advanced Photon Source. Recent test results with the PSPCD in the quadrant configuration as an X-ray beam-position monitor and in a multipixel array as an X-ray beam profiler are presented in this paper.

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Shu, Deming, Hai Ding, Juan Barraza, Tuncer M. Kuzay, Dean Haeffner, and Mohan Ramanathan. "Smart X-ray beam position monitor system using artificial-intelligence methods for the Advanced Photon Source insertion-device beamlines." Journal of Synchrotron Radiation 5, no. 3 (May 1, 1998): 632–35. http://dx.doi.org/10.1107/s0909049597017056.

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At the Advanced Photon Source (APS), each insertion-device (ID) beamline front end has two X-ray beam position monitors (XBPMs) to monitor the X-ray beam position for both vertical and horizontal directions. Performance challenges for a conventional photoemission-type XBPM during operations are contamination of the signal from the neighbouring bending-magnet sources and the sensitivity of the XBPM to the insertion-device gap variations. Problems are exacerbated because users change the ID gap during their operations, and hence the percentage level of the contamination in the front-end XBPM signals varies. A smart XBPM system with a high-speed digital signal processor has been built at the Advanced Photon Source for the ID beamline front ends. The new version of the software, which uses an artificial-intelligence method, provides a self-learning and self-calibration capability to the smart XBPM system. The structure of and recent test results with the system are presented in this paper.

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Di Fraia, Michele, Antonio De Sio, Matias Antonelli, Renzo Nesti, Dario Panella, Ralf H. Menk, Giuseppe Cautero, et al. "Fast beam monitor diamond-based devices for VUV and X-ray synchrotron radiation applications." Journal of Synchrotron Radiation 26, no. 2 (February 13, 2019): 386–92. http://dx.doi.org/10.1107/s1600577519000791.

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The improved performance of third-generation light sources and the advent of next-generation synchrotron radiation facilities require the use of extremely precise monitoring of the main photon-beam parameters, such as position, absolute and relative intensity, and temporal structure. These parameters, and associated real-time feedbacks, are fundamental at the beamline control level and at the machine control level, to improve the stability of the photon beams and to provide bunch-to-bunch quantitative information. Fast response time, high radiation hardness and visible–blind response are main features of photon-beam monitors for VUV and X-ray synchrotron radiation beamlines; hence diamond-based detectors are outstanding candidates. Here, results are presented of an extensive measurement campaign aiming at optimizing the capabilities of diamond detectors to discern time structures below the 100 ps timescale. A custom-built device has been fabricated and tested at the Italian Synchrotron Radiation Laboratory Elettra in Trieste. The results obtained show that diamond is an excellent material for ultra-fast photon pulses with picosecond time resolution; finally the possibilities for application at free-electron laser sources are discussed.

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22

Galimberti, A., R. Borghes, G. Paolucci, R. Presacco, G. Paolicelli, and G. Stefani. "First results of the novel photon beam position monitor for undulator beamlines of Elettra." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 467-468 (July 2001): 221–25. http://dx.doi.org/10.1016/s0168-9002(01)00278-9.

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23

Samadi, Nazanin, Xianbo Shi, and Dean Chapman. "Optimization of a phase-space beam position and size monitor for low-emittance light sources." Journal of Synchrotron Radiation 26, no. 6 (September 11, 2019): 1863–71. http://dx.doi.org/10.1107/s1600577519010658.

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The recently developed vertical phase-space beam position and size monitor (ps-BPM) system has proven to be able to measure the electron-source position, angle, size and divergence simultaneously in the vertical plane at a single location of a beamline. The optimization of the ps-BPM system is performed by ray-tracing simulation to maximize the instrument sensitivity and resolution. The contribution of each element is studied, including the monochromator, the K-edge filter, the detector and the source-to-detector distance. An optimized system is proposed for diffraction-limited storage rings, such as the Advanced Photon Source Upgrade project. The simulation results show that the ps-BPM system can precisely monitor the source position and angle at high speed. Precise measurements of the source size and divergence will require adequate resolution with relatively longer integration time.

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Shu, D., B. Rodricks, J. Barraza, T. Sanchez, and T. M. Kuzay. "The APS X-ray undulator photon beam position monitor and tests at CHESS and NSLS." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 319, no. 1-3 (August 1992): 56–62. http://dx.doi.org/10.1016/0168-9002(92)90531-8.

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Galimberti, A., R. Borghes, G. Paolucci, R. Presacco, G. Paolicelli, and G. Stefani. "Erratum to: “First results of the novel photon beam position monitor for undulator beamlines of Elettra”." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 480, no. 2-3 (March 2002): 828. http://dx.doi.org/10.1016/s0168-9002(01)02181-7.

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26

Lee, S. H., B. X. Yang, J. T. Collins, and M. Ramanathan. "Thermal management and prototype testing of Compton scattering X-ray beam position monitor for the Advanced Photon Source Upgrade." Review of Scientific Instruments 88, no. 2 (February 2017): 023106. http://dx.doi.org/10.1063/1.4975201.

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27

Shu, D., J. T. Collins, J. Barraza, and T. M. Kuzay. "The advanced photon source X-ray transmitting beam-position-monitor tests at the national synchrotron light source X-25 beamline." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 347, no. 1-3 (August 1994): 577–80. http://dx.doi.org/10.1016/0168-9002(94)91951-8.

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28

Pritchard, J. L., J. J. Velthuis, L. Beck, Y. Li, C. De Sio, L. Ballisat, J. Duan, Y. Shi, and R. P. Hugtenburg. "Complex field verification using a large area CMOS MAPS upstream in radiotherapy." Journal of Instrumentation 17, no. 08 (August 1, 2022): C08018. http://dx.doi.org/10.1088/1748-0221/17/08/c08018.

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Abstract A multileaf collimator (MLC) is an integral component in modern radiotherapy machines as it dynamically shapes the photon field used for patient treatment. Currently, the MLC leaves which collimate the treatment field are mechanically calibrated to ±1 mm every 3 months and during pre-treatment calibration are calibrated to the mechanically set leaf positions. Leaf drift can occur between calibration dates and hence exceed the ±1 mm tolerance. Pre-treatment verification, increases LINAC usage time so is seldom performed for each individual patient treatment, but instead for an acceptable sample of patients and/or treatment fractions. Independent real-time treatment verification is therefore desirable. We are developing a large area CMOS MAPS upstream of the patient to monitor MLC leaf positions for real-time treatment verification. CMOS MAPS are radiation hard for photon and electron irradiation, have high readout speeds and low attenuation which makes them an ideal upstream radiation detector for radiotherapy. Previously, we reported on leaf position reconstruction for single leaves using the Lassena, a 12 × 14 cm2, three side buttable MAPS suitable for clinical deployment. Sobel operator based methods were used for edge reconstruction. It was shown that the correspondence between reconstructed and set leaf position was excellent and resolutions ranged between 60.6 ± 8 and 109 ± 12 μm for a single central leaf with leaf extensions ranging from 1 to 35 mm using 0.3 sec of treatment beam time at 400 MU/min. Here, we report on leaf edge reconstruction using updated methods for complex leaf configurations, as occur in clinical use. Results show that leaf positions can be reconstructed with resolutions of 62 ± 6 μm for single leaves and 86 ± 16 μm for adjacent leaves at the isocenter using 0.15 sec at 400 MU/min of treatment beam. These resolutions are significantly better than current calibration standards.

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Hahn, U., W. Brefeld, M. Hesse, J. R. Schneider, H. Schulte-Schrepping, M. Seebach, and M. Werner. "Beam-position monitors in the X-ray undulator beamline at PETRA." Journal of Synchrotron Radiation 5, no. 3 (May 1, 1998): 627–29. http://dx.doi.org/10.1107/s0909049597013940.

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At the 12 GeV storage ring PETRA, the first synchrotron radiation beamline uses a 4 m-long undulator. The beamline, with a length of 130 m between source and sample, delivers hard X-ray photons usable up to 300 keV. The photon beam has a total power of 7 kW. Combined with the high brilliance, the powerful beam is very critical for all beamline components. Copper, located at a distance of 26 m, hit by the full undulator beam, melts within 20 ms. Different monitors are described for stable, safe and reliable operation of beam and experiments.

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Desjardins, Kewin, Michal Pomorski, and John Morse. "Ultra-thin optical grade scCVD diamond as X-ray beam position monitor." Journal of Synchrotron Radiation 21, no. 6 (October 4, 2014): 1217–23. http://dx.doi.org/10.1107/s1600577514016191.

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Results of measurements made at the SIRIUS beamline of the SOLEIL synchrotron for a new X-ray beam position monitor based on a super-thin single crystal of diamond grown by chemical vapor deposition (CVD) are presented. This detector is a quadrant electrode design processed on a 3 µm-thick membrane obtained by argon–oxygen plasma etching the central area of a CVD-grown diamond plate of 60 µm thickness. The membrane transmits more than 50% of the incident 1.3 keV energy X-ray beam. The diamond plate was of moderate purity (∼1 p.p.m. nitrogen), but the X-ray beam induced current (XBIC) measurements nevertheless showed a photo-charge collection efficiency approaching 100% for an electric field of 2 V µm−1, corresponding to an applied bias voltage of only 6 V. XBIC mapping of the membrane showed an inhomogeneity of more than 10% across the membrane, corresponding to the measured variation in the thickness of the diamond plate before the plasma etching process. The measured XBIC signal-to-dark-current ratio of the device was greater than 105, and the X-ray beam position resolution of the device was better than a micrometer for a 1 kHz sampling rate.

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Koch, Andreas, Johannes Risch, Wolfgang Freund, Theophilos Maltezopoulos, Marc Planas, and Jan Grünert. "Operation of photon diagnostic imagers for beam commissioning at the European XFEL." Journal of Synchrotron Radiation 26, no. 5 (August 19, 2019): 1489–95. http://dx.doi.org/10.1107/s1600577519008737.

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X-ray photon beam diagnostic imagers are located at 24 positions in the European XFEL beam transport system to characterize the X-ray beam properties, and to give feedback for tuning and optimization of the electron acceleration and orbit, the undulators, and the X-ray optics. One year of commissioning allowed experience to be gained with these imagers, which will be reported here. The sensitive Spontaneous Radiation imager is useful for various investigations in spontaneous radiation mode: for undulator adjustments and for low-signal imaging applications. The high-resolution Free-Electron Laser imager, 10 µm spatial resolution, is extensively used for the monitoring of beam position, spot size and shape, gain curve measurements, and also for beam-intensity monitoring. The wide field-of-view pop-in monitors (up to 200 mm) are regularly used for alignment and tuning of the various X-ray optical components like mirrors, slits and monochromators, and also for on-line beam control of a stable beam position at the instruments. The Exit Slit imager after the soft X-ray monochromator provides spectral information of the beam together with multi-channel plate based single-pulse gating. For particular use cases, these special features of the imagers are described. Some radiation-induced degradation of scintillators took place in this initial commissioning phase, providing useful information for better understanding of damage thresholds. Visible-light radiation in the beam pipe generated by upstream bending magnets caused spurious reflections in the optical system of some of the imagers which can be suppressed by aluminium-coated scintillating screens.

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Martin, BW, VE Fleischauer, and E. Muller. "Simultaneous in-situ x-ray beam profile and intensity measurements with a minimally invasive pixelated diamond monitor." Journal of Physics: Conference Series 2380, no. 1 (December 1, 2022): 012088. http://dx.doi.org/10.1088/1742-6596/2380/1/012088.

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Abstract Measuring x-ray beam position, profile, and intensity at synchrotron beamlines provides valuable information for all experiments. Sydor’s transparent x-ray camera (TXC), based on technology originally developed at Brookhaven National Laboratory[1], enables these measurements in-line with experiments for live feedback. The TXC has a low beam profile that fits within a standard vacuum flange width and is composed of diamond material for > 90% transmission of > 5 keV x-rays, minimizing disruption of beamline space and the x-ray beam itself. Standard device parameters include 32 x 32, 60 µm pitch pixels, linearity over a 107 – 1016 photons/s dynamic imaging range, < 40 pA noise floor, and total flux measurement mode. Device performance has been evaluated using a pinhole mask with a benchtop silver x-ray tube and during beam focusing tests at the XFP beamline at NSLS-II and flux characterization at the FAST beamline at CHESS. This work will highlight the features of this commercial beam diagnostic, test results, and future directions and applications of the technology.

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Chodankar, S., and Lin Yang. "Tools for rapid and reliable change of optical configuration at LIX." Journal of Physics: Conference Series 2380, no. 1 (December 1, 2022): 012040. http://dx.doi.org/10.1088/1742-6596/2380/1/012040.

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Abstract The LIX beamline (16-ID) at NSLS-II is a scattering beamline dedicated to probing structures in biological samples. The beamline supports both solution scattering and microbeam scanning structural mapping experiments. In addition to providing a stable and reliable beam, the beamline optical system must be able to quickly change configuration to support multiple modes of operation that require different beam properties such as photon energy and spot size, and with minimal effort from the experimenter. In order to do so, we have fine-tuned optical components and implemented automation. The beam stability is maintained using multiple beam position monitors and corresponding feedback on optical components. Vibrational stability of instruments is monitored and correspondingly mitigated. We describe the software and devices developed to automate configuration changes and outline the process of using these tools during operations.

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Katoh, M., Y. Hori, Y. Kobayashi, S. Sakanaka, M. Izawa, K. Haga, T. Honda, et al. "Reconstruction for the brilliance-upgrading project of the Photon Factory storage ring." Journal of Synchrotron Radiation 5, no. 3 (May 1, 1998): 366–68. http://dx.doi.org/10.1107/s0909049597014118.

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Reconstruction of the Photon Factory storage ring (PF ring; 2.5 GeV) is now in progress to provide very brilliant synchrotron radiation to users, i.e. the emittance is being reduced by a factor of five. Components, such as the quadrupole and sextupole magnets, vacuum chambers, beamlines and beam-position monitors, are being replaced by new ones in 16 normal-cell sections of the PF ring. The accelerating cavities, injection systems and control systems are also being replaced. Operation will commence when the improvements are completed on 1 October 1997.

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FERRARIO, M., V. FUSCO, M. MIGLIORATI, and L. PALUMBO. "EMITTANCE DEGRADATION DUE TO WAKE FIELDS IN A HIGH BRIGHTNESS PHOTOINJECTOR." International Journal of Modern Physics A 22, no. 23 (September 20, 2007): 4214–34. http://dx.doi.org/10.1142/s0217751x07037779.

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Wake fields effects in addition to space charge forces may have an important impact during the emittance compensation process in a high brightness photo-injector. To study this effect we developed an upgraded version of the Homdyn code including off axis beam dynamics and wake fields. Homdyn describes a bunch as a uniformly charged cylinder, divided in cylindrical slices; in the upgraded version each slice's centroid can be transversally displaced from the nominal axis thus inducing wake fields. When the bunch is short as compared to the beam pipe radius, wake fields for a single cavity are calculated using methods of diffraction theory; instead we use, for a periodic collection of cavities, an asymptotic wake field obtained numerically at SLAC and then fitted to a simple function. As a first application we studied and verified a correction scheme for the SPARC photo-injector to control the bunch trajectory and angle at the entrance of the undulator. The correction scheme consists of a number of steering magnets and beam position monitors placed along the photo-injector. Two different steering approaches are analyzed and the emittance degradation is studied. The code demonstrates the steering positions and number do correct the bunch's orbit and angle and gives good results concerning the emittance degradation. The emittance and energy spread degradation due to wake fields in the emittance meter experiment is also discussed.

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Enquist, Henrik, Andrius Jurgilaitis, Amelie Jarnac, Åsa U. J. Bengtsson, Matthias Burza, Francesca Curbis, Christian Disch, et al. "FemtoMAX – an X-ray beamline for structural dynamics at the short-pulse facility of MAX IV." Journal of Synchrotron Radiation 25, no. 2 (February 14, 2018): 570–79. http://dx.doi.org/10.1107/s1600577517017660.

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The FemtoMAX beamline facilitates studies of the structural dynamics of materials. Such studies are of fundamental importance for key scientific problems related to programming materials using light, enabling new storage media and new manufacturing techniques, obtaining sustainable energy by mimicking photosynthesis, and gleaning insights into chemical and biological functional dynamics. The FemtoMAX beamline utilizes the MAX IV linear accelerator as an electron source. The photon bursts have a pulse length of 100 fs, which is on the timescale of molecular vibrations, and have wavelengths matching interatomic distances (Å). The uniqueness of the beamline has called for special beamline components. This paper presents the beamline design including ultrasensitive X-ray beam-position monitors based on thin Ce:YAG screens, efficient harmonic separators and novel timing tools.

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He, Jun, Y. F. Sui, Y. Li, H. Z. Ma, Y. Y. Du, Y. Zhao, W. Zhang, et al. "Beam position monitor design for the high energy photon source." Measurement Science and Technology, July 19, 2022. http://dx.doi.org/10.1088/1361-6501/ac8277.

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Abstract A button and stripline beam position monitor (BPM) were designed and developed to achieve sub-micron orbit stability in the High Energy Photon Source (HEPS). Analytical formulae and CST electromagnetic simulation software were used to calculate the radio frequency characteristics of the BPM. The BPM design procedure was developed according to the HEPS requirements. The characteristic impedances of the stripline were designed to be 50 Ω and confirmed by measurements. The position sensitivity, position resolution, capacitance, and wakefield impedance of the button BPM were calculated. The measurement results confirmed that the design satisfied the HEPS requirements.

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Lee, S. H., P. Den Hartog, B. X. Yang, and G. Decker. "Development of a grazing-incidence insertion device X-ray beam position monitor at the Advanced Photon Source." Diamond Light Source Proceedings 1, MEDSI-6 (September 2010). http://dx.doi.org/10.1017/s2044820110000122.

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Beam stability is always a concern in synchrotron light source facilities, and accurate and stable X-ray beam position monitors (XBPM) are key elements in obtaining desired user beam stability. Currently, Advanced Photon Source is preparing to upgrade its facility to increase productivity and to provide better beam stability. For better beam stability, a grazing-incidence insertion device X-ray beam position monitor (GRID-XBPM) is proposed for the insertion device beamline front ends instead of the current photoemission-based XBPM. The design and development of the GRID-XBPM are summarized in this paper including the thermal simulation results of the GRID-XBPM. Thermal and stress analyses show that it withstands the 21 kW total beam power and the peak heat flux of 1684 W mm−2 at a grazing incidence angle of 0.80° using a heat transfer coefficient of 0.010 Wmm−2 °C−1.

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Sheng, I. C., C. K. Kuan, Y. T. Cheng, Y. H. Yan, G. Y. Hsiung, J. R. Chen, and C. L. Chen. "Status of Taiwan Photon Source front end in National Synchrotron Radiation Research Center." Diamond Light Source Proceedings 1, MEDSI-6 (October 2010). http://dx.doi.org/10.1017/s2044820110000341.

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National Synchrotron Radiation Research Center (NSRRC) in Taiwan has initialized the construction of Taiwan Photon Source (TPS) synchrotron accelerator project. This 3 GeV, 500 mA beam current third-generation synchrotron accelerator will have a total of seven insertion device beam lines at day 1 after commissioning. That is, there will be one 2 × EPU48, five IU22 and one U5 undulator beamline. Corresponding front end components such as fixed masks, photon beam position monitor, photon absorber, slits and heavy metal shutter have been designed; manufacturing of these subsystems are on the way. Several prototype assemblies are completed, tested and will be reported in this paper.

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Hsueh, H. P., I. T. Huang, C. C. Chang, S. N. Hsu, G. Y. Hsiung, and J. R. Chen. "Mechanical requirement and influence on the design and manufacturing of beam position monitor of Taiwan photon source." Diamond Light Source Proceedings 1, MEDSI-6 (March 2011). http://dx.doi.org/10.1017/s2044820111000086.

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The beam position monitors (BPMs) with submicron-level resolution act as the major eyes of storage ring in detecting the position of electron beams and are used for feedback system to guide the beam orbit to the desired track. Compared to major improvements on backend electronics, the physical devices generate and transmit signals had little improvement due to the lack of control on manufacturing processes including all mechanical tolerance requirements. The design started with ANSYS to simulate mechanical deformation. Due to the small size (submillimetre) and complicated assembly of feedthrough structure, it is difficult to achieve 1 % tolerance (submicron) in all aspects including machining and brazing. The smallest tolerance for machining is 5 µ and the overall tolerance will be 30 µm. The influence of the tolerance on mechanical will be shown on time-domain reflectometry measurement. The resulted heat-related issue will also be discussed and addressed since the problem happened at SLAC (private communication with Albert Sheng at Stanford Linear Accelerator Center) and DIAMOND (presented at the RF Button Heating Mini-Workshop at EPAC 2008). Manufacturing steps will be described. The consequence of mismatch on manufacturing will be discussed. All related measurement and simulation data are presented in this paper.

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Lascaud, Julie, Pratik Dash, Matthias Würl, Hans-Peter Wieser, Benjamin Wollant, Ronaldo Kalunga, Walter Assmann, et al. "Enhancement of the ionoacoustic effect through ultrasound and photoacoustic contrast agents." Scientific Reports 11, no. 1 (February 1, 2021). http://dx.doi.org/10.1038/s41598-021-81964-4.

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AbstractThe characteristic depth dose deposition of ion beams, with a maximum at the end of their range (Bragg peak) allows for local treatment delivery, resulting in better sparing of the adjacent healthy tissues compared to other forms of external beam radiotherapy treatments. However, the optimal clinical exploitation of the favorable ion beam ballistic is hampered by uncertainties in the in vivo Bragg peak position. Ionoacoustics is based on the detection of thermoacoustic pressure waves induced by a properly pulsed ion beam (e.g., produced by modern compact accelerators) to image the irradiated volume. Co-registration between ionoacoustics and ultrasound imaging offers a promising opportunity to monitor the ion beam and patient anatomy during the treatment. Nevertheless, the detection of the ionoacoustic waves is challenging due to very low pressure amplitudes and frequencies (mPa/kHz) observed in clinical applications. We investigate contrast agents to enhance the acoustic emission. Ultrasound microbubbles are used to increase the ionoacoustic frequency around the microbubble resonance frequency. Moreover, India ink is investigated as a possible mean to enhance the signal amplitude by taking advantage of additional optical photon absorption along the ion beam and subsequent photoacoustic effect. We report amplitude increase of up to 200% of the ionoacoustic signal emission in the MHz frequency range by combining microbubbles and India ink contrast agents.

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"Biological Tissue Characterization using Optical Backscattering Technique to detect the Presence of Abnormalities." International Journal of Engineering and Advanced Technology 9, no. 1S4 (December 30, 2019): 732–35. http://dx.doi.org/10.35940/ijeat.a1133.1291s419.

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we are using imaging modality to observe and acquire the information from the tissue. The backscattered intensity variation depends upon the composition, color and blood flow of the tissue. The optical parameters of the tissue are determined by using serial monitor in Arduino. Thus the tissues are treated of diameter 0.1, 0.2 and 0.3cm and placed at different depth. From this method, we can diagnose the abnormalities in the skin tissue/phantom. Photon depth distribution (anisotropy) and surface intensity differs which depends on various tissues. Thus scanned in horizontal position we have to find the depth. By peak intensity analysis, we have to determine the type, location and size of the tissue variation. Backscattering of laser from the tissue is measured by using optic probe. The backscattering parameter gives some information about the tissue because the light beam gets penetrate in some existence

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Bergonzo, P., D. Tromson, A. Brambilla, C. Mer, B. Guizard, and F. Foulon. "Diamond In-Line Monitors for Synchrotron Experiments." MRS Proceedings 590 (1999). http://dx.doi.org/10.1557/proc-590-125.

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ABSTRACTDiamond polycrystalline films have been synthesised using the Chemical Vapour Deposition (CVD) technique in order to fabricate new types of photo-detectors for the characterisation of x-ray light sources as encountered in synchrotron experiments. Since diamond exhibits a low absorption to low energy x-ray photons, these devices allow beam position monitoring with very little beam attenuation at photon energies as low as 2 keV. We present here diamond based new devices for four different applications, including (i) semitransparent beam intensity and (ii) position monitors with high position resolution (< 2 µm), (iii) beam profile monitors with 20 µm pitch resolution, and (iv) ultra-fast diamond detectors (response time < 100 ps) that enable the intensity and temporal monitoring of fast x-ray pulses. These devices can be used for in-line characterisation of synchrotron beam line experiments for permanent in-situ monitoring of beam instabilities during experiments as well as for synchrotron machine diagnostics.

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Feng, Bin, Lei Yu, Enwei Mo, Liyuan Chen, Jun Zhao, Jiazhou Wang, and Weigang Hu. "Evaluation of Daily CT for EPID-Based Transit In Vivo Dosimetry." Frontiers in Oncology 11 (November 2, 2021). http://dx.doi.org/10.3389/fonc.2021.782263.

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PurposeThe difference in anatomical structure and positioning between planning and treatment may lead to bias in electronic portal image device (EPID)-based in vivo dosimetry calculations. The purpose of this study was to use daily CT instead of planning CT as a reference for EPID-based in vivo dosimetry calculations and to analyze the necessity of using daily CT for EPID-based in vivo dosimetry calculations in terms of patient quality assurance.Materials and MethodsTwenty patients were enrolled in this study. The study design included eight different sites (the cervical, nasopharyngeal, and oral cavities, rectum, prostate, bladder, lung, and esophagus). All treatments were delivered with a CT-linac 506c (UIH, Shanghai) using 6 MV photon beams. This machine is equipped with diagnosis-level fan-beam CT and an amorphous silicon EPID XRD1642 (Varex Imaging Corporation, UT, USA). A Monte Carlo algorithm was developed to calculate the transmit EPID image. A pretreatment measurement was performed to assess system accuracy by delivering based on a homogeneous phantom (RW3 slab, PTW, Freiburg). During treatment, each patient underwent CT scanning before delivery either once or twice for a total of 268 fractions obtained daily CT images. Patients may have had a position correction that followed our image-guided radiation therapy (IGRT) procedure. Meanwhile, transmit EPID images were acquired for each field during delivery. After treatment, all patient CTs were reviewed to ensure that there was no large anatomical change between planning and treatment. The reference of transmit EPID images was calculated based on both planning and daily CTs, and the IGRT correction was corrected for the EPID calculation. The gamma passing rate (3 mm 3%, 2 mm 3%, and 2 mm 2%) was calculated and compared between the planning CT and daily CT. Mechanical errors [ ± 1 mm, ± 2 mm, ± 5 mm multileaf collimator (MLC) systematic shift and 3%, 5% monitor unit (MU) scaling] were also introduced in this study for comparing detectability between both types of CT.ResultThe average (standard deviation) gamma passing rate (3 mm 3%, 2 mm 3%, and 2 mm 2%) in the RW3 slab phantom was 99.6% ± 1.0%, 98.9% ± 2.1%, and 97.2% ± 3.9%. For patient measurement, the average (standard deviation) gamma passing rates were 87.8% ± 14.0%, 82.2% ± 16.9%, and 74.2% ± 18.9% for using planning CTs as reference and 93.6% ± 8.2%, 89.7% ± 11.0%, and 82.8% ± 14.7% for using daily CTs as reference. There were significant differences between the planning CT and daily CT results. All p-values (Mann–Whitney test) were less than 0.001. In terms of error simulation, nonparametric test shows that there were significant differences between practical daily results and error simulation results (p < 0.001). The receiver operating characteristic (ROC) analysis indicated that the detectability of mechanical delivery error using daily CT was better than that of planning CT. AUCDaily CT = 0.63–0.96 and AUCPlanning CT = 0.49–0.93 in MLC systematic shift and AUCDaily CT = 0.56–0.82 and AUCPlanning CT = 0.45–0.73 in MU scaling.ConclusionThis study shows the feasibility and effectiveness of using two-dimensional (2D) EPID portal image and daily CT-based in vivo dosimetry for intensity-modulated radiation therapy (IMRT) verification during treatment. The daily CT-based in vivo dosimetry has better sensitivity and specificity to identify the variation of IMRT in MLC-related and dose-related errors than planning CT-based.

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Journal articles on the topic 'Photon beam-position monitor'

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