Journal articles: 'Ion chamber'

1

Cockbaine, D. R. "Ion mobility scanning ion chamber." IEE Proceedings A Science, Measurement and Technology 140, no. 2 (1993): 155. http://dx.doi.org/10.1049/ip-a-3.1993.0025.

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Khrushchinsky, A. A., and S. A. Kuten. "Primary Ionization Density Produced by Charged Fragments in the Working Volume of the Fission Chambers." Nonlinear Phenomena in Complex Systems 24, no. 4 (December 10, 2021): 329–37. http://dx.doi.org/10.33581/1561-4085-2021-24-4-329-337.

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The question of the spatial distribution of ion pairs created by 235U fission fragments in the active volume of the fission chamber has been studied. The formulas of the spatial distribution of ion pairs in cylindrical fission chambers are proposed, which allows you to evaluate correctly the density of ion pairs in any point in the sensitive volume of the fission chamber

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Matsufuji, Naruhiro, Tetsuharu Matsuyama, Shinji Sato, and Toshiyuki Kohno. "Recombination characteristics of therapeutic ion beams on ion chamber dosimetry." International Journal of Modern Physics: Conference Series 44 (January 2016): 1660218. http://dx.doi.org/10.1142/s2010194516602180.

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In heavy ion radiotherapy, ionization chambers are regarded as a standard for determining the absorbed dose given to patients. In ion dosimetry, it is necessary to correct the radiation quality, which depends on the initial recombination effect. This study reveals for the radiation quality dependence of the initial recombination in air in ion dosimetry. Ionization charge was measured for the beams of protons at 40–160 MeV, carbon at 21–400 MeV/n, and iron at 23.5–500 MeV/n using two identical parallel-plate ionization chambers placed in series along the beam axis. The downstream chamber was used as a monitor operated with a constant applied voltage, while the other chamber was used for recombination measurement by changing the voltage. The ratio of the ionization charge measured by the two ionization chambers showed a linear relationship with the inverse of the voltage in the high-voltage region. The initial recombination factor was estimated by extrapolating the obtained linear relationship to infinite voltage. The extent of the initial recombination was found to increase with decreasing incident energy or increasing atomic number of the beam. This behavior can be explained with an amorphous track structure model: the increase of ionization density in the core region of the track due to decreasing kinetic energy or increasing atomic number leads to denser initial ion production and results in a higher recombination probability. For therapeutic carbon ion beams, the extent of the initial recombination was not constant but changed by 0.6% even in the target region. This tendency was quantitatively well reproduced with the track-structure based on the initial recombination model; however, the transitional change in the track structure is considered to play an important role in further understanding of the characteristics of the initial recombination.

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Elbashir, Fawzia E. M., Wassim Ksouri, Farouk Habbani, Ahmed M. El-Khayatt, Mohamed Hassan Eisa, and Ibrahim I. Suliman. "Analysis of Uncertainties in Clinical High-Energy Photon Beam Calibrations Using Absorbed Dose Standards." Applied Sciences 12, no. 8 (April 11, 2022): 3857. http://dx.doi.org/10.3390/app12083857.

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We compared the results of absorbed dose measurements made using the TRS-398, TG-51, and DIN protocols and their associated uncertainties to reduce discrepancies in measurement results made using the three protocols. This experiment was carried out on two Varian Medical linear accelerators with 4, 6, 10, and 20 MV photon energies using FC65-G and CC15 (cylindrical) and NACP-02-type (plane-parallel) ion chambers in water phantoms. The radiation beam quality index (Q) was determined from the measurement of percentage depth dose. It was used to determine the photon beam quality factor required with the ionization chamber calibration factor to convert the ion chamber reading into the absorbed dose to water. For the same beam quality, the TRS-398/TG-51 varied from 0.01% to 1.8%, whereas the ratio for TRS-398/DIN 6800-2 varied from 0.1% to 0.88%. The chamber-to-chamber variation was 0.09% in TRS-398/TG-51, 0.03% in TRS-398/DIN, and 0.02% in TG-51/DIN 6800-2. The expanded uncertainties (k = 1) were 1.24 and 1.25 when using TRS-398 and DIN 6800-2, respectively. Using the aforementioned three protocols, the results showed little chamber-to-chamber variation and uncertainty in absorbed dose measurements. The estimated uncertainties when using cylindrical ion chambers were slightly lower than those measured using plane-parallel chambers. The results are important in facilitating comparisons of absorbed dose measurements when using the three protocols.

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WELCH, D. R., D. V. ROSE, W. M. SHARP, C. L. OLSON, and S. S. YU. "Effects of preneutralization on heavy ion fusion chamber transport." Laser and Particle Beams 20, no. 4 (October 2002): 621–25. http://dx.doi.org/10.1017/s0263034602204279.

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Beams for heavy ion fusion are likely to require at least partial neutralization in the reactor chamber. Present target designs call for higher beam currents and smaller focal spots than most earlier designs, leading to high space-charge fields. Focusing is complicated by beam stripping in the low-pressure background gas expected in chambers. One method proposed for neutralization is passing an ion beam through a plasma before the beam enters the chamber. In this article, the electromagnetic particle-in-cell code LSP is used to study the effectiveness of this form of preneutralization for a range of plasma and beam parameters. For target chamber pressures below a few milliTorr of flibe gas, preneutralization is found to significantly reduce the beam emittance growth and spot size in the chamber.

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Mascali, D., A. Galatà, S. Gallo, O. Leonardi, G. S. Mauro, E. Naselli, A. Pidatella, F. Russo, G. Sorbello, and G. Torrisi. "Redefining plasma chambers for ECR Ion Sources: the IRIS structure." Journal of Physics: Conference Series 2244, no. 1 (April 1, 2022): 012003. http://dx.doi.org/10.1088/1742-6596/2244/1/012003.

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Abstract One possible way to optimize microwave coupling and plasma confinement in Electron Cyclotron Resonance (ECR) Ion Sources is a revolutionary design strategy of plasma chambers, breaking the cylindrical symmetry. This contribution reports about the design and numerical validation of an innovative resonant cavity playing as plasma chamber of ECR ion sources. The new chamber, named IRIS (Innovative Resonators for Ion Sources), was argued starting from the 3D structure of the plasma and, therefore, fashioned to the twisting magnetic structure. The microwave launching scheme was radically changed as well, consisting of side-coupled slotted-waveguides with diffractive apertures smoothly matching the overall structure of the camera. This approach also enables a profound optimization of cooling systems and overall spaces in general (for gas feedings, oven systems, sputtering, etc.). Here we report on the conceptual study, electromagnetic design and PIC simulations of the electron heating in the novel resonant cavity, comparing results with those for standard (cylindrical) chamber, and also considering the impact of microwave feeding led by single aperture rectangular waveguides vs. waveguide-slotted antennas. Manufacture strategy, based on additive manufacturing techniques, will also be discussed.

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Romero, Luciano, Roberto Santorelli, Edgar Sánchez García, Thorsten Lux, Michael Leyton, Silvestro di Luise, Pablo García Abia, et al. "Experimental Study of the Positive Ion Feedback from Gas to Liquid in a Dual-Phase Argon Chamber and Measurement of the Ion Mobility in Argon Gas." Universe 8, no. 2 (February 21, 2022): 134. http://dx.doi.org/10.3390/universe8020134.

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The dynamics of the positive ions created by particle interactions inside argon time projection chambers plays an important role in characterizing the next generation of massive detectors planned for the direct search for dark matter and the study of neutrino properties. We have constructed a 1 L liquid argon chamber (ARION: ARgon ION experiment) with a high voltage pulse generator capable of injecting, in a controlled manner, a sizeable ion current into the drift region. This chamber is capable of reproducing a volume charge similar to that found in large detectors, allowing its effects to be studied systematically. New experimental results regarding ion dynamics in the liquid and direct demonstration of ion feedback from the gas to the liquid are discussed in this paper. In addition, a novel technique to measure the drift velocity of argon ions is introduced along with preliminary results obtained in gas.

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Olson, Craig L. "Chamber transport for heavy ion fusion." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 733 (January 2014): 86–96. http://dx.doi.org/10.1016/j.nima.2013.05.089.

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9

Shumard, B., T. Pennington, D. J. Henderson, D. Seweryniak, K. E. Rehm, C. L. Jiang, C. N. Davids, C. J. Lister, B. J. Zabransky, and B. Blank. "Transmission ion chamber: Design and application." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 241, no. 1-4 (December 2005): 446–49. http://dx.doi.org/10.1016/j.nimb.2005.07.055.

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10

Asada, Yasuki. "Measurement of Output by Ion Chamber." Japanese Journal of Radiological Technology 66, no. 4 (2010): 66_4_I. http://dx.doi.org/10.6009/jjrt.66.66_4_i.

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11

Ma, Xiao-Yun, Yan-Shan Zhang, Wan-Bin Meng, Yin Qi, Qiang Li, Yan-Cheng Ye, and Jia-Ming Wu. "Energy-Related Scatter Analysis for Determining the Effective Point of Measurement of Cylindrical Ion Chamber in Heavy Charged Particle Carbon Ion Beam." BioMed Research International 2021 (October 22, 2021): 1–13. http://dx.doi.org/10.1155/2021/8808537.

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Purpose. An experimental and mathematical study for determining the effective point of measurement ( P eff ) for a Farmer-type cylindrical chamber in a carbon ion passive scatter beam is presented. Methods. The ionization depth curves measured by the Bragg peak chamber were plotted according to the position of the inner surface of the entrance window, while the Farmer chamber was plotted at the tip of the cylindrical geometric center. The ionization depth curves measured by a cylindrical chamber in the 3D water phantom were then compared with a high-precision parallel-plate PTW Bragg peak chamber for inspecting the upstream shift correction of the cylindrical chamber in the carbon ion beam. A component of the vertical and horizontal integration method and the barrier model, cos φ = 1 − 2 α R L / 1 + α − R L , for analyzing the shift of effective point of measurement in different carbon ion energies and various field sizes, were studied. Results. The shift between the maximum peak of the Bragg peak chamber and the Farmer chamber in a field size of 10 cm × 10 cm with an energy of 330 MeV/u of carbon ion is 2.3 mm. This upstream shift corresponds to 0.744 ± 0.07 r , where r is the Farmer chamber inner radius of 3.05 mm. Carbon ion energy from 120 MeV/u to 400 MeV/u with different field sizes show different shifts of effective point of measurement in a range of 0.649 ± 0.02 r to 0.843 ± 0.06 r of 3 cm × 3 cm at an energy of 400 MeV/u and 10 cm × 10 cm at an energy of 120 MeV/u, respectively. The vertical and horizontal scatter analysis by the barrier model can precisely describe the shift of the effective point of measurement at different carbon ion energies with various field sizes. Conclusions. We conclude that the Farmer chamber can be used for a patient-specific dose verification check in carbon ion beam treatment if P eff is well calibrated.

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12

Pradhan, Harapriya, Omkar A. Shinde, Makarand M. Ghangrekar, and Supriya Sarkar. "Bioremediation of Steel Plant Wastewater and Improved Electricity Generation in Bio-Electrochemical Desalination Cell." Advanced Materials Research 1130 (November 2015): 648–51. http://dx.doi.org/10.4028/www.scientific.net/amr.1130.648.

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A new technology called microbial desalination cell (MDC) approaches a comprehensive way to design an innovative system for removal of organic matter and dissolved solids from wastewater. In this study, two laboratory scale MDCs having three chambered (3C-MDC) and five chambered (5C-MDC) configuration were developed for integrated biodegradation of steel plant wastewater. The 3C-MDC have anodic, middle desalination and cathodic chamber; while 5C-MDC have anodic, cathodic, middle desalination and two concentrate chambers separated by ion exchange membranes. Using synthetic saline water with 8 and 30 g/L of TDS and steel plant wastewater (3.74 g TDS/L) in desalination chamber, the TDS removal of 64 ± 2.3%, 75 ± 1.8%, and 58 ± 1.3% were observed in 3C-MDC, while in 5C-MDC, those were 58 ± 1.5%, 71 ± 2.1%, and 64 ± 2.4%, respectively in 96 h of fed batch operation. With 30 g/L of TDS concentration, the power generation observed in 3C-MDC and 5C-MDCs were (81 mW/m2 and 78 mW/m2) higher than the power observed with 8 g/L (56 mW/m2 and 45 mW/m2). However, with steel plant wastewater in desalination chamber the power density increased to 76 mW/m2 in 5C-MDC and significantly decreased to 39 mW/m2 in 3C-MDC.

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13

Morrow, Robert C., and Theodore W. Tibbitts. "Air Ion Exposure System for Plants." HortScience 22, no. 1 (February 1987): 148–51. http://dx.doi.org/10.21273/hortsci.22.1.148.

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Abstract A system was developed for subjecting plants to elevated air ion levels. This system consisted of a rectangular Plexiglas chamber lined with a Faraday cage. Air ions were generated by corona discharge from frayed stainless steel fibers placed at one end of the chamber. This source was capable of producing varying levels of either positive or negative air ions. During plant exposures, environmental conditions were controlled by operating the unit in a growth chamber.

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Marks, L. D., M. Kubozoe, M. Tomita, M. Ukiana, T. Furutsu, and T. Matsui. "Design and initial performance of a UHV-HREM." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 658–59. http://dx.doi.org/10.1017/s0424820100105357.

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We report here on the basic design and the initial performance of a fully bakeable UHV-HREM. The instrument, see Figure 1,is based upon a conventional H-9000 electron microscope with the natural differential pumping of the column separating the standard gun and photographic chambers from the UHV specimen chamber. The addition of small ion pumps at the condenser aperture, the selected area aperture and between the two projector lenses (see Figure 2) (which attain operational pressures of ∼2 X 10-8, ∼2 X 10-8 and ∼2 X 10-7 Torr respectively) assist this differential pumping. To achieve full UHV performance the specimen region is bakeable to 200°C using a combination of tape and band heaters and quartz-halogen lamps. Specimens for HREM analysis can be pretreated in the transfer chamber which is shown in Figure 3. The specimens, held in a detachable side entry cartridge, can be moved both back and forward and rotated by 360° to face ports onto which equipment for LEED, ion beam, X-ray, evaporation and dye laser treatment of surfaces will be mounted; the transfer chamber acts as a conventional multi-port surface science chamber.

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15

GRISHAM, L. R. "Potential roles for heavy negative ions as driver beams." Laser and Particle Beams 21, no. 4 (October 2003): 545–48. http://dx.doi.org/10.1017/s0263034603214117.

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We have performed an initial assessment of the feasibility of producing heavy negative ion beams as drivers for an inertial confinement fusion reactor. Negative ion beams offer the potentially important advantages relative to positive ions that they will not draw electrons from surfaces and the target chamber plasma during acceleration, compression, and focusing, and they will not have a low energy tail. Intense negative ion beams could also be efficiently converted to atomically neutral beams by photodetachment prior to entering the target chamber. Depending on the target chamber pressure, this atomic beam will undergo ionization as it crosses the chamber, but at chamber pressures at least as high as 1.3 × 10−4 torr, there may still be significant improvements in the beam spot size on the target, due to the reduction in path-averaged self-field perveance. The halogens, with their large electron affinities, are the best negative ion candidates. Fluorine and chlorine are the easiest halogens to use for near-term source experiments, whereas bromine and iodine best meet present expectations of driver mass. With regard to ion sources and photodetachment neutralizers, this approach should be feasible with existing technology. Except for the target chamber, the vacuum requirements for accelerating and transporting high energy negative ions are essentially the same as for positive ions.

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Anvari, Akbar, Seyed Mahmoud Reza Aghamiri, Seyed Rabie Mahdavi, and Parham Alaei. "Statistical analysis on 2D array of ion chamber performance." Journal of Radiotherapy in Practice 14, no. 2 (January 12, 2015): 194–201. http://dx.doi.org/10.1017/s1460396914000442.

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AbstractPurposeIn this work, dosimetric properties of the PTW Octavius detector in and out of the irradiation field have been evaluated. The 2D array of ion chambers has the potential to simplify the linear accelerator QA and pre-treatment verification.Materials and methodsThe evaluation was performed using customised written codes in Matlab and SPSS software for statistical analysis.ResultsExperiments indicate that the reproducibility and stability of the measurements were excellent; the detector showed the same signal with a maximum deviation of <0·5% in the short and long term. Comparisons of the ion chamber with the detector showed the same results with a maximum deviation of ~0·1%. As the detector response is linear with the dose, it can be used for the measurement at regions of high-dose gradient effectively. Logarithmic regression y=0·127 ln(x)+0·729 for detector signal and field size changes yielded a coefficient of determination of 0·997. The dose value decreases with increase in source-to-surface distance, which was modelled using a binomial regression with a coefficient of determination of 0·998 that agrees with the ionisation chamber measurement within 1%.ConclusionOn the basis of the measurements and comparisons performed, this system is a reliable and accurate dosimeter for quality assurance in radiotherapy.

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Brücken, Erik, and Timo Hildén. "GEM Foil Quality Assurance For The ALICE TPC Upgrade." EPJ Web of Conferences 174 (2018): 03004. http://dx.doi.org/10.1051/epjconf/201817403004.

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The ALICE (A Large Ion Collider Experiment) experiment at the Large Hadron Collider (LHC) at CERN is dedicated to heavy ion physics to explore the structure of strongly interacting matter. The Time Projection Chamber (TPC) of ALICE is a tracking detector located in the central region of the experiment. It offers excellent tracking capabilities as well as particle identification. After the second long shutdown (LS2) the LHC will run at substantially higher luminosities. To be able to increase the data acquisition rate by a factor of 100, the ALICE TPC experiment has to replace the Multi-Wire Proportional Chamber (MWPC) –based readout chambers. The MWPC are operated with gating grid that limits the rate to O(kHz). The new ReadOut Chamber (ROC) design is based on Gas Electron Multiplier (GEM) technology operating in continuous mode. The current GEM productions scheme foresees the production of more than 800 GEM foils of different types. To fulfill the requirements on the performance of the GEM TPC readout, necessitates thorough Quality Assurance (QA) measures. The QA scheme, developed by the ALICE collaboration, will be presented in detail.

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He Wusheng, 贺武生, 孙安邦 Sun Anbang, 毛根旺 Mao Genwang, 霍超 Huo Chao, and 陈茂林 Chen Maolin. "Numerical simulation of ion thruster discharge chamber." High Power Laser and Particle Beams 22, no. 12 (2010): 3020–24. http://dx.doi.org/10.3788/hplpb20102212.3020.

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Sharp, William M., Debra A. Callahan, Max Tabak, Simon S. Yu, Per F. Peterson, Dale R. Welch, David V. Rose, and Craig L. Olson. "Modeling Chamber Transport for Heavy-Ion Fusion." Fusion Science and Technology 43, no. 3 (May 2003): 393–400. http://dx.doi.org/10.13182/fst03-a283.

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Callahan, Debra A. "Chamber propagation physics for heavy ion fusion." Fusion Engineering and Design 32-33 (November 1996): 441–52. http://dx.doi.org/10.1016/s0920-3796(96)00500-5.

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Kudryavtsev, Yu, T. E. Cocolios, J. Gentens, M. Huyse, O. Ivanov, D. Pauwels, T. Sonoda, P. Van den Bergh, and P. Van Duppen. "Dual chamber laser ion source at LISOL." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 267, no. 17 (September 2009): 2908–17. http://dx.doi.org/10.1016/j.nimb.2009.06.013.

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Watanabe, N. "Compensator for angular response of ion chamber." Journal of Physics E: Scientific Instruments 20, no. 2 (February 1987): 174–76. http://dx.doi.org/10.1088/0022-3735/20/2/010.

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Szymanski, J. J., J. D. Bowman, P. P. J. Delheij, C. M. Frankle, J. Knudson, S. Penttilä, S. J. Seestrom, S. H. Yoo, V. W. Yuan, and X. Zhu. "Ion chamber system for neutron flux measurements." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 340, no. 3 (March 1994): 564–71. http://dx.doi.org/10.1016/0168-9002(94)90139-2.

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Saminathan, Sathiyan, Henry Finlay Godson, Retna Ponmalar, Ravikumar Manickam, James Mazarello, and Rahul Fernandes. "Dosimetric Performance of Newly Developed Farmer-Type Ionization Chamber in Radiotherapy Practice." Technology in Cancer Research & Treatment 15, no. 6 (July 9, 2016): NP113—NP120. http://dx.doi.org/10.1177/1533034615621635.

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Dose measurement with ionization chamber is essential to deliver accurate dose to the tumor in radiotherapy. The cylindrical Farmer-type ionization chamber is recommended by various dosimetry protocols for dose measurement of radiotherapy beams. The air-equivalent graphite wall Farmer-type ionization chamber (FAR 65 GB) of active volume 0.65 cm3 with aluminum as the central electrode material was fabricated. Various dosimetric parameters were studied for the newly developed ionization chamber in cobalt-60, 6 and 18 MV photon beams. The preirradiation and postirradiation leakage of the chamber was within 0.08%. The long-term stability and the stem effect of the chamber were within 0.07% and 0.3%, respectively. The sensitivity of the ionization chamber was found to be 22.15 nC/Gy. The chamber shows linear response with dose for cobalt-60, 6 and 18 MV photon beams. The ion recombination correction factor increases with increase in bias voltage. For all energies and field sizes, the polarity correction factor is almost closer to unity. The ion recombination and polarity correction measurements show that the polarizing potential and polarity recommended during the calibration of ionization chamber should be used for routine measurement to avoid the uncertainty. The chamber response is independent of dose rate and energy. The chamber is cost-effective and shows precise and reproducible response. The study carried out confirms that the newly fabricated ion chamber can be used in the measurement of absolute dose for high-energy photon beams.

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Avdic, Senada, Adnan Beganovic, Armin Lagumdzija, Samra Sadikovic, Beco Pehlivanovic, Damir Demirovic, and Irma Kadic. "Comparative analysis of gamma dose rates measured by ion chamber in and around the historical sacral objects in Bosnia and Herzegovina." Nuclear Technology and Radiation Protection 34, no. 2 (2019): 157–64. http://dx.doi.org/10.2298/ntrp181122013a.

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The main objective of this study was to investigate the correlation between the indoor and outdoor ambient dose equivalent rates measured by the ion chamber inside and around the historical sacral objects at a few locations in Bosnia and Herzegovina. The investigated objects made of the traditional building materials were built in the Late Medieval, Post Medieval, and Ottoman Period of Bosnia and Herzegovina history. The LUDLUM Model 9DP instrument based on a pressurized ion chamber was selected for natural low level radiation measurements since the ionisation chambers have higher sensitivities than the other types of detectors. The detection capability of the LUDLUM Model 9DP pressurized ion chamber was examined in the laboratory conditions with a source of low activity and under natural environmental radiation conditions by measuring the indoor and outdoor dose rates. A weak positive correlation was found between the ambient dose equivalent rates inside the historical sacral objects and the dose rates outside the objects. The average evaluated value of the indoor to outdoor dose rate ratio of 1.07 for the studied historic objects is less than that obtained for the contemporary building materials such as concrete. No study on the indoor to outdoor dose rate ratio in Bosnia and Herzegovina measured by the LUDLUM 9DP dose rate meter based on an ion chamber has been conducted yet. In addition to direct measurements, the first gamma spectrometric analysis of a few samples of building materials from the Late Medieval period in Bosna and Herzegovina was performed. The results of the gamma analysis revealed almost uniform distribution of primordial radionuclides in the investigated samples. It was demonstrated that such materials had the reduced content of radioactive isotopes compared to the contemporary building materials and therefore they could have potential advantages in specific applications related to the environmentally sustainable architecture.

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Pradhan, Harapriya, and M. M. Ghangrekar. "Multi-chamber microbial desalination cell for improved organic matter and dissolved solids removal from wastewater." Water Science and Technology 70, no. 12 (November 1, 2014): 1948–54. http://dx.doi.org/10.2166/wst.2014.438.

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A five-chamber microbial desalination cell (MDC) with anode, cathode, one central desalination chamber and two concentrate chambers separated by ion exchange membranes was operated in batch mode for more than 60 days. The performance of the MDC was evaluated for chemical oxygen demand (COD) removal, total dissolved solids (TDS) removal and energy production. An average COD removal of 81 ± 2.1% was obtained using acetate-fed wastewater as substrate in the anodic chamber inoculated with mixed anaerobic sludge. TDS removals of 58, 70 and 78% were observed with salt concentration of 8, 20 and 30 g/L, respectively, in the middle desalination chamber. The MDC produced a maximum power output of 16.87 mW/m2 during polarization. The highest Coulombic efficiency of 12 ± 2.4% was observed in this system using mixed anaerobic sludge as inoculum. The system effectively demonstrated capability for simultaneous organic matter removal and desalination along with power generation.

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Begum, Afia, and Nobuhisa Takata. "Recombination Parameters of some Fabricated Ionization Chambers." Bangladesh Journal of Medical Physics 4, no. 1 (April 20, 2013): 101–6. http://dx.doi.org/10.3329/bjmp.v4i1.14694.

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Some pancake and spherical type ionization chambers of various size have been designed and fabricated for absolute air kerma measurement in 60Co and 137Cs ?-ray fields at the Primary Standard Dosimetry Laboratory (PSDL), National Institute of Advanced Industrial Science & Technology (AIST), Tsukuba, Japan. Values of recombination parameters A and m2g of these ionization chambers are obtained using a method proposed by De Almeida and Niatel and adopted by Boutillon. For absolute air kerma measurement, it is important to obtain accurate signal currents by correcting it for ion losses using the values of A and m2g of each of the ionization chambers. It has been observed from the measurements that the recombination parameters for pancake ionization chamber are smaller than spherical ionization chambers and for spherical type ionization chamber recombination parameter values depend on the dimensions of the electrodes and also the size of the chambers. DOI: http://dx.doi.org/10.3329/bjmp.v4i1.14694 Bangladesh Journal of Medical Physics Vol.4 No.1 2011 101-106

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Rondo, L., A. Kürten, S. Ehrhart, S. Schobesberger, A. Franchin, H. Junninen, T. Petäjä, M. Sipilä, D. R. Worsnop, and J. Curtius. "Effect of ions on the measurement of sulfuric acid in the CLOUD experiment at CERN." Atmospheric Measurement Techniques 7, no. 11 (November 19, 2014): 3849–59. http://dx.doi.org/10.5194/amt-7-3849-2014.

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Abstract. Ternary aerosol nucleation experiments were conducted in the CLOUD chamber at CERN in order to investigate the influence of ions on new particle formation. Neutral and ion-induced nucleation experiments, i.e. without and with the presence of ions, respectively, were carried out under precisely controlled conditions. The sulfuric acid concentration was measured with a chemical ionisation mass spectrometer (CIMS) during the new particle formation experiments. The added ternary trace gases were ammonia (NH3), dimethylamine (DMA, C2H7N) or oxidised products of pinanediol (PD, C10H18O2). When pinanediol was introduced into the chamber, an increase in the mass spectrometric signal used to determine the sulfuric acid concentration (m/z 97, i.e. HSO4−) was observed due to ions from the CLOUD chamber. The enhancement was only observed during ion-induced nucleation measurements by using either galactic cosmic rays (GCRs) or the proton synchrotron (PS) pion beam for the ion generation, respectively. The ion effect typically involved an increase in the apparent sulfuric acid concentration by a factor of ~ 2 to 3 and was qualitatively verified by the ion measurements with an atmospheric-pressure interface-time of flight (APi-TOF) mass spectrometer. By applying a high-voltage (HV) clearing field inside the CLOUD chamber, the ion effect on the CIMS measurement was completely eliminated since, under these conditions, small ions are swept from the chamber in about 1 s. In order to exclude the ion effect and to provide corrected sulfuric acid concentrations during the GCR and PS beam nucleation experiments, a parameterisation was derived that utilises the trace gas concentrations and the UV light intensity as input parameters. Atmospheric sulfuric acid measurements with a CIMS showed an insignificant ion effect.

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Rondo, L., A. Kürten, S. Ehrhart, S. Schobesberger, A. Franchin, H. Junninen, T. Petäjä, M. Sipilä, D. R. Worsnop, and J. Curtius. "Effect of ions on the measurement of sulphuric acid in the CLOUD experiment at CERN." Atmospheric Measurement Techniques Discussions 7, no. 7 (July 3, 2014): 6595–624. http://dx.doi.org/10.5194/amtd-7-6595-2014.

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Abstract. Ternary aerosol nucleation experiments were conducted in the CLOUD chamber at CERN in order to investigate the influence of ions on new particle formation. Neutral and ion-induced nucleation experiments, i.e., with and without the presence of ions, were carried out under precisely controlled conditions. The sulphuric acid concentration was measured with a Chemical Ionization Mass Spectrometer (CIMS) during the new particle formation experiments. The added ternary trace gases were ammonia (NH3), dimethylamine (DMA, C2H7N) or oxidised products of pinanediol (PD, C10H18O2). When pinanediol was introduced into the chamber, an increase in the mass spectrometric signal used to determine the sulphuric acid concentration (m/z 97, i.e., HSO4−) was observed due to ions from the CLOUD chamber. The enhancement was only observed during ion-induced nucleation measurements by using either galactic cosmic rays (GCR) or the proton synchrotron (PS) pion beam for the ion generation, respectively. The ion effect typically involved an increase in the apparent sulphuric acid concentration by a factor of ~2 to 3 and was qualitatively verified by the ion measurements by an Atmospheric Pressure interface-Time Of Flight (APi-TOF) mass spectrometer. By applying a high voltage (HV) clearing field inside the CLOUD chamber the ion effect on the CIMS measurement was completely eliminated since, under these conditions, small ions are swept from the chamber in about one second. In order to exclude the ion effect and to provide corrected sulphuric acid concentrations during the GCR and PS beam nucleation experiments, a parameterisation was derived that utilizes the trace gas concentrations and the UV light intensity as input parameters. Atmospheric sulphuric acid measurements with a CIMS showed an insignificant ion effect.

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Franchin, A., S. Ehrhart, J. Leppä, T. Nieminen, S. Gagné, S. Schobesberger, D. Wimmer, et al. "Experimental investigation of ion–ion recombination under atmospheric conditions." Atmospheric Chemistry and Physics 15, no. 13 (July 1, 2015): 7203–16. http://dx.doi.org/10.5194/acp-15-7203-2015.

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Abstract. We present the results of laboratory measurements of the ion–ion recombination coefficient at different temperatures, relative humidities and concentrations of ozone and sulfur dioxide. The experiments were carried out using the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber at CERN, the walls of which are made of conductive material, making it possible to measure small ions. We produced ions in the chamber using a 3.5 GeV c−1 beam of positively charged pions (π+) generated by the CERN Proton Synchrotron (PS). When the PS was switched off, galactic cosmic rays were the only ionization source in the chamber. The range of the ion production rate varied from 2 to 100 cm−3 s−1, covering the typical range of ionization throughout the troposphere. The temperature ranged from −55 to 20 °C, the relative humidity (RH) from 0 to 70 %, the SO2 concentration from 0 to 40 ppb, and the ozone concentration from 200 to 700 ppb. The best agreement of the retrieved ion–ion recombination coefficient with the commonly used literature value of 1.6 × 10−6 cm3 s−1 was found at a temperature of 5 °C and a RH of 40 % (1.5 ± 0.6) × 10−6 cm3 s−1. At 20 °C and 40 % RH, the retrieved ion–ion recombination coefficient was instead (2.3 ± 0.7) × 10−6 cm3 s−1. We observed no dependency of the ion–ion recombination coefficient on ozone concentration and a weak variation with sulfur dioxide concentration. However, we observed a more than fourfold increase in the ion–ion recombination coefficient with decreasing temperature. We compared our results with three different models and found an overall agreement for temperatures above 0 °C, but a disagreement at lower temperatures. We observed a strong increase in the recombination coefficient for decreasing relative humidities, which has not been reported previously.

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Garty, G., A. D. Harken, and D. J. Brenner. "Traceable dosimetry for MeV ion beams." Journal of Instrumentation 17, no. 02 (February 1, 2022): T02002. http://dx.doi.org/10.1088/1748-0221/17/02/t02002.

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Abstract Standard dosimetry protocols exist for highly penetrating photon and particle beams used in the clinic and in research. However, these protocols cannot be directly applied to shallow penetration MeV-range ion beams. The Radiological Research Accelerator Facility has been using such beams for almost 50 years to irradiate cell monolayers, using self-developed dosimetry, based on tissue equivalent ionization chambers. To better align with the internationally accepted standards, we describe implementation of a commercial, NIST-traceable, air-filled ionization chamber for measurement of absorbed dose to water from low energy ions, using radiation quality correction factors calculated using TRS-398 recommendations. The reported dose does not depend on the ionization density in the range of 10–150 keV/μm.

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Fu, S. H., L. C. Tian, and Z. F. Ding. "Effects of secondary γ-electrons from accelerator grid under ion impingement in gridded ion sources." Plasma Sources Science and Technology 31, no. 2 (February 1, 2022): 025004. http://dx.doi.org/10.1088/1361-6595/ac3968.

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Abstract Thus far, effects of secondary γ-electrons emitted from accelerator grids (AGs) of gridded ion sources on ionization in discharge chambers have not been studied. The presence and induced processes of such secondary electrons in a microwave electron cyclotron resonance gridded ion source are confirmed by the consistent explanations of: (1) the observed jump of ion beam current (I b) in case of a low-density plasma appearing at the chamber’s radial center due to the microwave skin effect; (2) the evolution of glow images recorded from the end-view of the ion source during the jump of I b; (3) the over-large jump step of I b with increasing microwave power; (4) the pattern appearing on the temperature sticker exposed to the discharge operated in the regime where the arrayed energetic-electron beamlets are injected into the discharge chamber; (5) the measured step-increment in the voltage drop across the screen grid (SG) sheath. A positive feedback loop composed of involved processes is established to elucidate the underlying mechanism. Energetic γ-electrons from the AG and warm δ-electrons from the opposite antenna do not produce direct excitation and ionization, but they enhance the electrical confinement of cold electrons by elevating the voltage drop across the sheaths at the antenna and SG, thus leading to the jump of I b. The energetic γ-electrons-based model can be also modified to explain abnormal results observed in the other gridded ion sources. Energetic γ-electrons from AGs should be taken into account in understanding gridded ion sources.

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Fu, Yu-Liang, Juan Yang, Bin Wang, Zhan Hu, Xu Xia, and Hao Mou. "Numerical study on abnormal flameout of 2-cm electron cyclotron resonance ion source." Acta Physica Sinica 71, no. 8 (2022): 085203. http://dx.doi.org/10.7498/aps.71.20212151.

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A 2-cm electron cyclotron resonance ion source has the advantages of long life and high specific impulse, which can meet the requirements for space gravitational waves detection. In the experiment on finding the lower limit of thrust, it is found that when the ion source operates under the extreme condition of 0.5-W microwave power and 0.1-sccm gas flow rate, increasing the voltages of grid system excessively may cause flameout. The plasma discharge level is controlled by the gas supply, microwave, and power supply system, and their small disturbances will make experimental results different, thus the flameout of the ion source appears randomly and transiently. Besides, it is difficult to observe the flameout phenomenon experimentally, because the probe diagnosis has big interference to low-density plasma, and the optical diagnosis is blocked by the grid system. Therefore, the integrative simulation with the full particle-in-cell method is used to simulate the operating process of the ion source, whose calculation range includes the discharge chamber, grid system, and plume. Through simulating the processes of plasma discharge and ion beam extraction continuously in space and time, the flameout phenomenon can be reproduced artificially after increasing the voltages of grid system. The simulation results show that the ambipolar diffusion between the antenna and discharge chamber is the fundamental reason for the flameout of the ion source. In the circuit, the antenna does not touch the discharge chamber but for bulk plasma, which makes its surface gradually accumulate charges until it reaches the floating potential. Because the increase of the voltage of antenna lags behind that of grid system, a strong electric field will appear between the antenna and chamber. Then, electrons and ions respectively move toward the chamber and antenna, the ambipolar diffusion helps the antenna reach the floating potential rapidly. When the plasma density inside the chamber is low, the ambipolar diffusion will cause flameout. In order to avoid the flameout of the ion source in such an extreme situation, an improvement measure that the voltage of antenna equals the voltage of chamber is proposed, which is verified by the integrative simulation. The study on the flameout phenomenon will provide a theoretical basis for the design and application of the ion source, which can help the ion source operate safely to meet the requirements for space gravitational wave detection.

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Kim, Chungyong, and Gyu-Sik Kim. "Improvement of a Radon Counter Sensitivity Using High-Voltage Ion Chamber." International Journal of Trend in Scientific Research and Development Volume-2, Issue-4 (June 30, 2018): 951–54. http://dx.doi.org/10.31142/ijtsrd14257.

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35

Mizuno, T., N. S. Park, H. Tsuno, and T. Hidaka. "Evaluating effective volume and hydrodynamic behavior in a full-scale ozone contactor with computational fluid dynamics simulation." Water Supply 4, no. 5-6 (December 1, 2004): 277–88. http://dx.doi.org/10.2166/ws.2004.0118.

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An ozone reaction model combined with CFD (Computational Fluid Dynamics) technique was developed in this research. In the simulation of ozonation, hydrodynamic behavior caused by bubbling of ozone contacting-gas is important as well as reaction kinetics. CFD technique elucidated hydrodynamic behavior in the selected ozone contactor, which consisted of three main chambers. Back-mixing zone was found in each chamber. The higher velocities of water were observed in the second and third chambers than that in the first one. The flow of the opposite direction to the main flow was observed near the water surface. Based on the results of CFD simulation, each chamber was divided into small compartments, and hydrodynamic behavior and effective volume were discussed. Mass balance equations were also established in each compartment with reaction terms associated with DOC, odor compounds, bacteria, bromide ion and bromate ion. This reaction model was intended to predict dissolved ozone concentration, especially. We concluded that the model could predict favourably the mass balance of ozone, namely absorption efficiency of gaseous ozone, dissolved ozone concentration and ozone consumption. After establishing the model, we discussed the effects of hydrodynamic behavior on dissolved ozone concentration.

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Surette, R. A., and M. J. Wood. "Evaluation of Electret Ion Chamber for Tritium Measurement." Health Physics 65, no. 4 (October 1993): 418–21. http://dx.doi.org/10.1097/00004032-199310000-00010.

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Herrup, D., J. Chu, H. Cheung, and M. Pankuch. "Determination of penumbral widths from ion chamber measurements." Medical Physics 32, no. 12 (November 16, 2005): 3636–40. http://dx.doi.org/10.1118/1.2128086.

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Prasad, K. R., V. Balagi, P. M. Dighe, Mary Alex, and R. Karpagam. "Pressurized ion chamber for low energy radiation monitoring." Radiation Measurements 27, no. 4 (July 1997): 593–98. http://dx.doi.org/10.1016/s1350-4487(97)00019-x.

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Welch, D. R., D. V. Rose, B. V. Oliver, and R. E. Clark. "Simulation techniques for heavy ion fusion chamber transport." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 464, no. 1-3 (May 2001): 134–39. http://dx.doi.org/10.1016/s0168-9002(01)00024-9.

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40

Bandyopadhyaya, S. K., S. K. Basu, S. Bhattacharya, R. K. Bhowmik, A. Chakrabarti, S. K. Datta, G. S. N. Murthy, and Y. P. Viyogi. "An axial ionization chamber for heavy ion identification." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 278, no. 2 (June 1989): 467–69. http://dx.doi.org/10.1016/0168-9002(89)90866-8.

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Junfang, Chen, and Ren Zhaoxing. "Ion energy distribution in an ECR plasma chamber." Vacuum 52, no. 4 (April 1999): 411–14. http://dx.doi.org/10.1016/s0042-207x(98)00323-6.

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42

Simon, Thomas A., Jakub Kozelka, William E. Simon, Darren Kahler, Jonathan Li, and Chihray Liu. "Characterization of a multi-axis ion chamber array." Medical Physics 37, no. 11 (November 1, 2010): 6101–11. http://dx.doi.org/10.1118/1.3505452.

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43

Khan, Faiz M. "Replacement correction (P repl ) for ion chamber dosimetry." Medical Physics 18, no. 6 (November 1991): 1244–46. http://dx.doi.org/10.1118/1.596597.

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44

Clarke, Lane L. "A guide to Ussing chamber studies of mouse intestine." American Journal of Physiology-Gastrointestinal and Liver Physiology 296, no. 6 (June 2009): G1151—G1166. http://dx.doi.org/10.1152/ajpgi.90649.2008.

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The Ussing chamber provides a physiological system to measure the transport of ions, nutrients, and drugs across various epithelial tissues. One of the most studied epithelia is the intestine, which has provided several landmark discoveries regarding the mechanisms of ion transport processes. Adaptation of this method to mouse intestine adds the dimension of investigating genetic loss or gain of function as a means to identify proteins or processes affecting transepithelial transport. In this review, the principles underlying the use of Ussing chambers are outlined including limitations and advantages of the technique. With an emphasis on mouse intestinal preparations, the review covers chamber design, commercial equipment sources, tissue preparation, step-by-step instruction for operation, troubleshooting, and examples of interpretation difficulties. Specialized uses of the Ussing chamber such as the pH stat technique to measure transepithelial bicarbonate secretion and isotopic flux methods to measure net secretion or absorption of substrates are discussed in detail, and examples are given for the adaptation of Ussing chamber principles to other measurement systems. The purpose of the review is to provide a practical guide for investigators who are new to the Ussing chamber method.

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45

Cox, M. J., M. J. Kim, Hong Xu, and R. W. Carpenter. "Silicon Wafer Bonding: Effect of Wafer Surface Treatment on Interface Structure and Chemistry." Microscopy and Microanalysis 6, S2 (August 2000): 1074–75. http://dx.doi.org/10.1017/s1431927600037867.

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The two most important characteristics of any surface considered for wafer bonding are cleanliness, surface smoothness and macroscopic flatness. Silicon wafers in the as-received condition have a native oxide on the surface several nanometers thick [1], Figure la shows that they also have a layer of hydrocarbons. While they are not clean, they are smooth. Our wafers were plasma or ion cleaned, chemically treated, and ultra high vacuum (UHV) thermal desorption annealed in different combinations to find the best method for providing smooth, contamination free substrates that will produce an atomically flat, chemically clean Si/Si bonded interface.The first approach was a single step process to remove the contaminants and then bond the clean wafers. Cleaning was accomplished by ion bombardment of the surface in an UHV chamber with base pressure 1x109 Torr. This ion cleaning chamber is connected between the UHV (2x10-10 ) bonding chamber and UHV (1x10-10) analysis chamber, allowing wafers to be cleaned, analyzed, and bonded without breaking vacuum [2].

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NIGMATZYANOV, Vladislav V., Veniamin A. POGODIN, Lev N. RABINSKIY, Sergey A. SITNIKOV, and Thant ZIN HEIN. "POLYMER PRECURSORS FOR CREATING GAS DISCHARGE CHAMBER FOR ELECTRIC ROCKET ENGINE." Periódico Tchê Química 17, no. 35 (July 20, 2020): 560–68. http://dx.doi.org/10.52571/ptq.v17.n35.2020.47_nigmatzyanov_pgs_560_568.pdf.

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Electric rocket engines are widely used in space technology. Furthermore, at present, electric propulsion engines are also used as mid-flight engines for flights in interplanetary space. On modern spacecraft, the following types of electric propulsion are mostly used: SPT and grid ion thruster. When using these engines as sustainers, it is important is to increase the total power for obtaining the required thrust and specific impulse. With an increase in total power, the volume of the discharge chamber increases, which leads to technological difficulties in the manufacture of discharge chambers from ceramic materials. Thus, the task of finding alternative ceramic materials is relevant and necessary in the development of high-frequency ion thrusters. The article discusses the issues of creating a composite material based on woven quartz materials and organosilicon binder as a precursor filled with silicon nitride for the manufacture of gas discharge chamber (GDC) of high-frequency ion thruster (RFIT). By thermos-gravimetric analysis, a thermosetting binder, which meets the requirements of vibration resistance and electromagnetic permeability of GDC in the megahertz range, was selected. Based on the binder filled with silicon nitride powder, reinforced by quartz woven fabrics, manufactured GDC. The resulting product was tested as part of the laboratory electric propulsion device with a diameter of 100 mm and power of 200W.

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47

de Izarra, Grégoire. "COSICAF, a fission chamber simulation tool for academic purposes." EPJ Nuclear Sciences & Technologies 6 (2020): 49. http://dx.doi.org/10.1051/epjn/2020011.

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Nuclear instrumentation is a complex topic since it involves a wide range of physics phenomena like nuclear reactions, heavy ion interactions with matter, electrostatic, charge creation etc. Understanding and modelling fission chambers is a difficult task usually performed with Monte-Carlo and finite element simulations. Since a few years, analytical and simplified Monte Carlo models were introduced at the French Atomic Energy Commission to easily design detectors. It is proposed here to present the derivation of such model, called COSICAF, for academic purposes; this numerical model provided with this article, will help students and researchers to understand and design fission chambers. To demonstrate the interest and the limitation of proposed work in research field, the model is applied to simulate two real miniature fission chamber designs.

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Lekatou, Aristea, Vasiliki Peppa, Pantelis Karaiskos, Evangelos Pantelis, and Panagiotis Papagiannis. "On the potential of 2D ion chamber arrays for high-dose rate remote afterloading brachytherapy quality assurance." Physics in Medicine & Biology 67, no. 8 (April 8, 2022): 085011. http://dx.doi.org/10.1088/1361-6560/ac612d.

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Abstract Objective. To investigate the potential of 2D ion chamber arrays to serve as a standalone tool for the verification of source strength, positioning and dwell time, within the framework of 192Ir high-dose rate brachytherapy device quality assurance (QA). Approach. A commercially available ion chamber array was used. Fitting of a 2D Lorentzian peak function to experimental data from a multiple source dwell position irradiation on a frame-by-frame basis, facilitated tracking of the source center orthogonal projection on the array plane. For source air kerma strength verification, Monte Carlo simulation was employed to obtain a chamber array- and source-specific correction factor of calibration with a 6 MV photon beam. This factor converted the signal measured by each ion chamber element to air kerma in free space. A source positioning correction was also applied to lift potential geometry mismatch between experiment and Monte Carlo simulation. Main results. Spatial and temporal accuracy of source movement was verified within 0.5 mm and 0.02 s, respectively, in compliance with the test endpoints recommended by international professional societies. The source air kerma strength was verified experimentally within method uncertainties estimated as 1.44% (k = 1). The source positioning correction method employed did not introduce bias to experimental results of irradiations where source positioning was accurate. Development of a custom jig attachable to the chamber array for accurate and reproducible experimental set up would improve testing accuracy and obviate the need for source positioning correction in air kerma strength verification. Significance. Delivery of a single irradiation plan, optimized based on results of this work, to a 2D ion chamber array can be used for concurrent testing of source position, dwell time and air kerma strength, and the procedure can be expedited through automation. Chamber arrays merit further study in treatment planning QA and real time, in vivo dose verification.

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Nariyama, Nobuteru. "Current saturation in free-air ionization chambers with chopped synchrotron radiation." Journal of Synchrotron Radiation 20, no. 5 (July 3, 2013): 698–704. http://dx.doi.org/10.1107/s0909049513016154.

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Saturation curves for free-air ionization chambers with electrode gap widths of 4.2, 8.4 and 18 mm were obtained for 10 and 15 keV undulator synchrotron radiation thinned with a 230 Hz rotating-disk chopper. Ion recombination in free-air ionization chambers was found to be inversely proportional to the applied electric field, and an expression that satisfactorily reproduced the ion-recombination rate is determined. A comparison of the expressions for continuous and pulsed X-rays revealed that chopped high-intensity X-rays require a higher voltage to attain saturation when the product of the pulse width and electric field exceeds a value that depends on the X-ray energy. This behaviour was observed explicitly for 10 keV X-rays in measurements with the ionization chamber placed before and after the chopper.

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Аруев, Н. Н., М. А. Козловский, М. Ф. Кудояров, М. Я. Патрова, П. А. Романов, Р. В. Тюкальцев, И. Л. Федичкин, and С. В. Филиппов. "Исследование состава остаточного газа в вакуумной системе циклотрона ФТИ им. А.Ф. Иоффе." Письма в журнал технической физики 45, no. 16 (2019): 30. http://dx.doi.org/10.21883/pjtf.2019.16.48153.17860.

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4. Using the FT-200 compact-size time-of-flight mass spectrometer developed at the Ioffe Institute, the mass spectra of the residual gas molecules in the vacuum system of the Ioffe Institute cyclotron have been obtained under various experimental conditions. The measurements were carried out in the cyclotron vacuum chamber and the end part of the ion guide near the sample irradiation chamber. It was found that the main contribution to the residual gas composition in the cyclotron chamber is made by the molecules of pump oil used (up to 82%) and water molecules (up to 15-17%), and in the ion guide near the irradiation chamber with a polymer film - water molecules (up to 63%). The data obtained are the basis for the modernization of the Ioffe cyclotron complex.

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Journal articles on the topic 'Ion chamber'

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