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Radiation Failure Mechanisms
Published in Judy Pecht, Michael Pecht, Long-Term Non-Operating Reliability of Electronic Products, 2019
Another solution is to remove radioactive species from the package materials. These are easier to remove from plastic packages, in which only the filler must be considered, than from hermetic packages. The main difficulty of this method is detecting low-level radioactivity, an expensive process. Large-area gas proportional flow counting, sophisticated gamma spectroscopy, liquid scintillation, and nuclear track counting are techniques for measuring low-level radioactivity. Scintillation detectors are easy to use, economical, and efficient; however, they are subject to high background radiation levels. Gas proportional flow detectors are useful because large-area detectors can reduce count time. Nuclear film tracking has the advantage that films can be left unattended for weeks or months. Finally, atmospheric factors, such as airborne radon, may contaminate wafers and open packages during fabrication and measurement, which requires very low background levels in order to resolve low count rates.
Measurement of Radiation
Published in Philip T. Underhill, Naturally Occurring Radioactive Material, 2018
Scintillation is the mechanism by which a material emits light upon interaction with ionizing radiation. For a particular type of radiation, the intensity of the light emitted is related to the energy of the incident radiation (it should be noted that this relationship is not linear). The light can be measured and equated to radiation exposure.
Radiation Sources, Exposure, and Health Effects
Published in James H. Saling, Audeen W. Fentiman, Radioactive Waste Management, 2018
James H. Saling, Audeen W. Fentiman
Measurement devices. Some of the devices commonly used to measure ionizing radiation include ionization chambers, proportional counters, Geiger–Mueller counters, scintillation detectors, and semiconductor detectors. The most important application of ionization chambers is in the measurement of gamma-ray exposure. Proportional counters are very important in the detection and spectroscopy of low-energy x radiation and the detection of neutrons. A Geiger tube can only function as a counter because all energy information about the incident radiation is lost. Scintillation detectors can be composed of organic or inorganic crystals. Organic crystals are best used in beta spectroscopy and fast neutron detection, whereas inorganic crystals are better for gamma-ray spectroscopy. There are also two main types of semiconductor detectors. The silicon semiconductor is used mainly for charged particle spectroscopy and the germanium semiconductor is used more often in gamma-ray measurements.5
Gamma ray and fast neutron shielding of ZrSiO4-Al2O3 ceramic refractor
Published in Particulate Science and Technology, 2023
Mahmoud Gharieb, Sayed H. Kenawy, Gehan T. El-Bassyouni, Esmat M. A. Hamzawy
Sodium iodide NaI (Tl) scintillation detector housed in a 16 mm thick lead jacket with a 5 mm diameter holed collimator, joined with a computerized analyzer was used to rate the gamma rays radiation attenuation coefficient of specimens (Al-Humaiqani, Shuraim, and Hussain 2013; Yamada, Ishizu, and Kawada 2013). sodium iodide (NaI) crystals are the most widely used scintillation material for gamma ray spectroscopy. Their high light output and the excellent match to the sensitivity of photomultiplier tubes, provide good, economical energy resolution. The standard radiation sources contained radioactive elements of Cs137 − 0.662 MeV and Co60 − 1.173, and 1.332 MeV; with activities of five micro Curie (5 µ Ci). The setup for the gamma radioactive testing is presented in Figure 1. With the intention to determine the linear attenuation coefficient (µ) of gamma rays, we measured the fractional radiation intensity of samples (Ix) at thickness (x) compared with the source intensity of gamma rays designated (Io), while the solution of the exponential Beer–Lambert’s law was used to attain the attenuation coefficient (µ) (More, Lokhande, and Pawar 2016; Malidarre et al. 2020; Gharieb et al. 2021).
Improvements in the particle and heavy-ion transport code system (PHITS) for simulating neutron-response functions and detection efficiencies of a liquid organic scintillator
Published in Journal of Nuclear Science and Technology, 2022
Charged particles (i.e. protons, deuterons, tritons, 3He ions, alpha particles, and recoil nuclei) produced by nuclear reactions impart their energies to the scintillator and concomitantly create fluorescent light by the excitation of the molecules of the scintillation material. In SCINFUL–QMD, the light outputs given in the electron-equivalent energies (MeVee) are quantified directly from the kinetic energies of the charged particles using the conversion tables and equations [6] that convolute the fluorescence and quenching processes. For secondary gamma rays emitted from the excited nuclei, Compton scattering inside the scintillator is sampled by the Monte Carlo technique until they escape from the scintillator or their energies become less than 30 keV, in which case, the total absorption of the remaining energy is assumed. The light outputs of the scattered electrons are deduced from their kinetic energies. In addition, further collisions of the secondary neutrons are examined on the pathway from the initial interaction spot to the surface of the scintillator along the flight direction. If a collision occurs, the nuclear-reaction, energy-deposition, and light-output processes are simulated as described above. The transport simulations are terminated when the neutrons fly out from the scintillator or when their energies degrade below the cut-off energy level of 0.1 MeV.
Design and Characterization of a Scintillator-Based Position-Sensitive Detector for Muon Imaging
Published in Nuclear Technology, 2019
Can Liao, Haori Yang, Zhengzhi Liu, Jason P. Hayward
Organic plastic scintillation detectors are widely used in many radiation sensing applications due to their low cost, stability, fast response time, and sensitivity to all kinds of radiation. The decay time of organic plastic scintillators usually lies in the range of several nanoseconds compared to hundreds of nanoseconds or more in many other types of detectors, so organic scintillators have an excellent capacity to handle high-radiation background environments such as those encountered near dry nuclear fuel storage casks. Moreover, some field applications require mobility of the detector system. For example, in a recently proposed muon-based computed tomography method, the detector system needs to be rotated multiple times to generate a complete image.16 Gas detectors like drift tubes contain tiny wires that are extremely sensitive to vibration. In comparison, plastic scintillators with ruggedized photomultiplier (PMT) or silicon-based photon sensors can be much more mechanically robust. Also, unlike inorganic scintillators that are barely possible to be manufactured in large sizes and have little machinability, Polyvinyltoluene (PVT)-based plastic scintillators offer great flexibility in detector size and shape. Therefore, a PVT-based plastic scintillator is chosen to be the material for detecting muons in our study. In this work, we propose a scintillator-based detector with incorporated multiplexing circuits used for muon imaging. The goal was to achieve ~1-cm detector resolution.