Gamma‐Ray Induced Conductivity in Polyethylene and Teflon under Radiation at High Dose Rate

1963 ◽  
Vol 34 (4) ◽  
pp. 804-809 ◽  
Author(s):  
Kichinosuke Yahagi ◽  
Akibumi Danno
Keyword(s):  
Dose Rate ◽  
Gamma Ray ◽  
High Dose Rate ◽  
High Dose

Development of a simultaneous imaging system to measure the optical and gamma ray images of Ir-192 source for high-dose-rate brachytherapy

2021 ◽  
Vol 16 (12) ◽  
pp. T12005
Author(s):  
J. Nagata ◽  
S. Yamamoto ◽  
Y. Noguchi ◽  
T. Nakaya ◽  
K. Okudaira ◽  
...  
Keyword(s):  
Dose Rate ◽  
Spatial Resolution ◽  
Gamma Camera ◽  
Gamma Ray ◽  
Imaging System ◽  
High Dose Rate ◽  
High Dose ◽  
Cmos Camera ◽  
Absolute Position ◽  
The Absolute

Abstract In high-dose-rate (HDR) brachytherapy, verification of the Ir-192 source's position during treatment is needed because such a source is extremely radioactive. One of the methods used to measure the source position is based on imaging the gamma rays from the source, but the absolute position in a patient cannot be confirmed. To confirm the absolute position, it is necessary to acquire an optical image in addition to the gamma ray image at the same time as well as the same position. To simultaneously image the gamma ray and optical images, we developed an imaging system composed of a low-sensitivity, high-resolution gamma camera integrated with a CMOS camera. The gamma camera has a 1-mm-thick cerium-doped yttrium aluminum perovskite (YAIO3: YAP(Ce)) scintillator plate optically coupled to a position-sensitive photomultiplier (PSPMT), and a 0.1-mm-diameter pinhole collimator was mounted in front of the camera to improve spatial resolution and reduce sensitivity. We employed the concept of a periscope by placing two mirrors tilted at 45 degrees facing each other in front of the gamma camera to image the same field of view (FOV) for the gamma camera and the CMOS camera. The spatial resolution of the imaging system without the mirrors at 100 mm from the Ir-192 source was 3.2 mm FWHM, and the sensitivity was 0.283 cps/MBq. There was almost no performance degradation observed when the mirrors were positioned in front of the gamma camera. The developed system could measure the Ir-192 source positions in optical and gamma ray images. We conclude that the developed imaging system has the potential to measure the absolute position of an Ir-192 source in real-time clinical measurements.

Dose Rate Effects in Fluorescence Chemical Dosimeters Exposed to Picosecond Electron Pulses: An Accurate Measurement of Low Doses at High Dose Rates

2021 ◽  
Author(s):  
Martin Precek ◽  
Petr Kubelik ◽  
Ludek Vysin ◽  
Uli Schmidhammer ◽  
Jean-Philippe Larbre ◽  
...  
Keyword(s):  
Dose Rate ◽  
Gamma Ray ◽  
High Dose Rate ◽  
Attractive Alternative ◽  
High Dose ◽  
Low Doses ◽  
Solution Ph ◽  
Short Pulses ◽  
Dose Rates ◽  
Trimesic Acid

The development of ultra-intense electron pulse for applications needs to be accompanied by the implementation of a practical dosimetry system. In this study four different systems were investigated as dosimeters for low doses with a very high-dose-rate source. First, the effects of ultra-short pulses were investigated for the yields of the Fricke dosimeter based on acidic solutions of ferrous sulfate; it was established that the yields were not significantly affected by the high dose rates, so the Fricke dosimeter system was used as a reference. Then, aqueous solutions of three compounds as fluorescence chemical dosimeters were utilized, each operated at a different solution pH: terephthalic acid - basic, trimesic acid - acidic, and coumarin-3- carboxylic acid (C3CA) - neutral. Fluorescence chemical dosimeters offer an attractive alternative to chemical dosimeters based on optical absorption for measuring biologically relevant low doses because of their higher sensitivity. The effects of very intense dose rate (TGy/s) from pulses of fast electrons generated by a picosecond linear accelerator on the chemical yields of fluorescence chemical dosimeters were investigated at low peak doses (<20 Gy) and compared with yields determined under low-dose-rate irradiation from a 60 Co gamma-ray source (mGy/s). For the terephthalate and the trimesic acid dosimeters changes in the yields were not detected within the estimated (∼10%) precision of the experiments, but, due to the complexity of the mechanism of the hydroxyl radical initiated reactions in solutions of the relevant aromatic compounds, significant reductions of the chemical yield (–60%) were observed when the C3CA dosimeter was irradiated with the ultra-short pulses.

scholarly journals A Performance Evaluation of a Notebook PC under a High Dose-Rate Gamma Ray Irradiation Test

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Jai Wan Cho ◽  
Kyung Min Jeong
Keyword(s):  
Performance Evaluation ◽  
Dose Rate ◽  
Nuclear Power ◽  
Gamma Ray ◽  
Control Unit ◽  
High Dose Rate ◽  
High Dose ◽  
Robot System ◽  
Irradiation Test ◽  
Gamma Ray Irradiation

We describe the performance of a notebook PC under a high dose-rate gamma ray irradiation test. A notebook PC, which is small and light weight, is generally used as the control unit of a robot system and loaded onto the robot body. Using TEPCO’s CAMS (containment atmospheric monitoring system) data, the gamma ray dose rate before and after a hydrogen explosion in reactor units 1–3 of the Fukushima nuclear power plant was more than 150 Gy/h. To use a notebook PC as the control unit of a robot system entering a reactor building to mitigate the severe accident situation of a nuclear power plant, the performance of the notebook PC under such intense gamma-irradiation fields should be evaluated. Under a similar dose-rate (150 Gy/h) gamma ray environment, the performances of different notebook PCs were evaluated. In addition, a simple method for a performance evaluation of a notebook PC under a high dose-rate gamma ray irradiation test is proposed. Three notebook PCs were tested to verify the method proposed in this paper.

Obtaining High-Dose-Rate $\gamma$ -Ray Detection With Commercial Off-the-Shelf CMOS Pixel Sensor Module

2019 ◽  
Vol 19 (16) ◽  
pp. 6729-6735 ◽  
Author(s):  
Shoulong Xu ◽  
Shuliang Zou ◽  
Yongchao Han ◽  
Taoyi Zhang ◽  
Yantao Qu
Keyword(s):  
Dose Rate ◽  
Gamma Ray ◽  
High Dose Rate ◽  
High Dose ◽  
Sensor Module ◽  
Commercial Off The Shelf

scholarly journals Study on the axial distribution of radioactivity in 60Co source pencils for high dose-rate irradiation and that of gamma-ray intensity.

RADIOISOTOPES ◽  
1988 ◽  
Vol 37 (8) ◽  
pp. 452-455 ◽  
Author(s):  
Takao YAMAMOTO ◽  
Tokuhiro OHNISHI ◽  
Shigeki NAKAMURA ◽  
Shinichi OKAMOTO
Keyword(s):  
Dose Rate ◽  
Gamma Ray ◽  
High Dose Rate ◽  
High Dose ◽  
Axial Distribution ◽  
60Co Source

Operation of field emitter arrays under high dose rate gamma-ray irradiation

2018 ◽  
Author(s):  
Teruyuki Morito ◽  
Yusuke Handa ◽  
Yasuhito Gotoh ◽  
Nobuhiro Sato ◽  
Ikuji Takagi ◽  
...  
Keyword(s):  
Dose Rate ◽  
Gamma Ray ◽  
High Dose Rate ◽  
High Dose ◽  
Field Emitter ◽  
Field Emitter Arrays ◽  
Gamma Ray Irradiation
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