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Semiconductor Detectors
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
The TlBr is a compound semiconductor material that currently mainly exists at an experimental stage: commercial TlBr crystals are available but are not yet as ready-to-use detector systems. TlBr used as a spectrometric detector for γ-radiation was first reported in the mid-eighties, although research on mixed thallium bromide/iodide as detector for ionizing radiation was initiated much earlier [43]. TlBr is a competitive future low-cost alternative to CZT for room-temperature use. CZT currently being the only room-temperature operated high-resolution semiconductor detector for γ-spectrometry. Properties of TlBr and the competitive scintillator materials BGO and LYSO are listed in Table 7.3
Solid-State Dose Measuring Devices
Published in W. P. M. Mayles, A. E. Nahum, J.-C. Rosenwald, Handbook of Radiotherapy Physics, 2021
The detection threshold depends both on the electrometer and on the active volume and doping level of the semiconductor detector. The pre-irradiation dose and the doses subsequently accumulated also have an influence on it. For commercially available systems and pre-irradiated diodes, the detection threshold varies from 0.1 cGy to some tenths of cGy.
Radiation Safety
Published in Debbie Peet, Emma Chung, Practical Medical Physics, 2021
Debbie Peet, Elizabeth Davies, Richard Raynor, Alimul Chowdhury
For CT scanners and linear accelerators, which have much longer exposure times than the few milliseconds of diagnostic X-ray exposure, the dose rate outside the room might be measured directly using a dose rate meter (Figure 7.12). This might be a scintillation detector, an energy-compensated Geiger Muller tube, or a semiconductor detector. The choice of source and detector can depend on the environment, sensitivity required, and required accuracy of the measurement, as described by Knoll (2010). Measurements are taken along a barrier in a raster movement and recorded as spot measurements for locations along the barrier at waist, head and ankle height.
Regulatory implementation of the occupational equivalent dose limit for the lens of the eye and underlying relevant efforts in Japan
Published in International Journal of Radiation Biology, 2023
Sumi Yokoyama, Nobuyuki Hamada, Norio Tsujimura, Naoki Kunugita, Kazutaka Nishida, Iwao Ezaki, Masahiro Kato, Hideki Okubo
The National Metrology Institute of Japan (NMIJ) provides the primary standards including dosimetric quantities, and has determined the filter conditions for the standard radiation quality RQR (radiation qualities in radiation beams emerging from the X-ray tube assembly) fields that are specified in IEC 61267: 2005 (IEC 2005) and were used in testing and calibration of the eye lens dosimeters in the project of the European Radiation Dosimetry Group (EURADOS) (Vanhavere et al. 2012). Calibration and testing are also possible in the RQR field, in addition to the abovementioned L/N/W/H series, 60Co, and 137Cs. Table 4 shows the filter conditions for the RQR X-ray fields. Comparing with the values of other irradiation fields reported in the other literature, the filter thickness is slightly different even with the same RQR index. The air kerma to Hp(3) and H′(3) conversion coefficients for the RQR fields were derived from the field energy spectrum and monochromatic X-ray conversion factor. NMIJ has also derived the air kerma to Hp(3) and H′(3) conversion coefficients for the continuous filtered X radiation based on the quality index (QI) series specified in JIS Z 4511:2018 (JSA 2018a) and ISO 4037-3:2019 (ISO 2019c). The conversion coefficients are described in Appendix. The energy spectrum of the RQR field was calculated by the Monte Carlo N-Particle (MCNP) code, and those of the QI series were measured by the semiconductor detector.
Properties of IBA Razor Nano Chamber in small-field radiation therapy using 6 MV FF, 6 MV FFF, and 10 MV FFF photon beams
Published in Acta Oncologica, 2021
Mari Partanen, Jarkko Niemelä, Jarkko Ojala, Jani Keyriläinen, Mika Kapanen
In this work, properties of the Nano chamber ionization chamber were assessed in small RT fields. The Nano chamber was compared with two commercially available and small-field recommended detectors, namely the IBA Razor Diode semiconductor detector and the PTW microDiamond (PTW-Freiburg GmbH, Freiburg, Germany) synthetic diamond detector. Moreover, the traditional PTW Semiflex ionization chamber was used for comparison in larger fields. The IBA Stealth ionization chamber (attached to the linac using the interface mount) was used as a reference signal detector relative measurements in small fields of 2 and the IBA CC13 ionization chamber (positioned to be outside the radiation beam) in larger fields. The following bias voltages were used in the measurements: 300 V for the Nano chamber, 0 V for the Razor Diode, 0 V for the microDiamond, 400 V for the Semiflex, −420 V for the Steath and 300 V for the CC13. In this study, the measurement results were not corrected for the polarity effect.
Development of UV–visible spectrophotometric methods for the quantitative and in silico studies for cilazapril optimized by response surface methodology
Published in Drug Development and Industrial Pharmacy, 2021
To make a precise interpretation of the important characteristics of FTIR spectra of the donor–acceptor complex along with acceptor, a KBr pellet method was applied. A Perkin Elmer Fourier transform infrared (FTIR) spectrometer (Perkin Elmer, Waltham, MA) with total reflection accessory of resolution 4 cm−1 and 40 scans was used. The electronic absorption spectra were recorded in the UV–visible region ranging from 200 to 700 nm exploiting UV-1800 SHIMADZU UV spectrophotometer (Kyoto, Japan). Powder X-ray diffraction technique was used to perceive the nature of the formed complex. Being nondestructive to sample outdo this technique with other characterization techniques used. Rigaku Powder X-ray diffractometer (Tokyo, Japan) with 9 kW rotating anode based high flux PhotonMax X-ray source backed by HyPix-3000 high-energy-resolution 2D multidimensional semiconductor detector was used. The scan rate of 10°/min with samples scanned in the range of 5°–80°.