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Borate Phosphors for Radiation Dosimetery
Published in S. K. Omanwar, R. P. Sonekar, N. S. Bajaj, Borate Phosphors, 2022
The main types of radiation detectors are as follows:Gas-filled detectorsScintillation detectorsSemiconductor detectorsThermoluminescence detectors (TLDs)Optically stimulated luminescence detector (OSLDs)Cerenkov counterNuclear track detectorsNeutron detectors
Growth of ZnO for Neutron Detectors
Published in Zhe Chuan Feng, Handbook of Zinc Oxide and Related Materials, 2012
Eric A. Burgett, Elisa N. Hurwitz, Nolan E. Hertel, Christopher J. Summers, Jeff Nause, Na Lu, Ian T. Ferguson
Neutrons are particularly difficult to detect because, as the name indicates, they are neutral particles. Detecting them requires a material with a large cross section for charged particle production. The lighter atomic (low Z) materials tend to center around a handful of nuclei whose inner spin-orbit coupling is near to either one or a pair of magic numbers. A magic number is a number of nucleons (protons or neutrons) that can be arranged into complete shells within the atomic nucleus [11]. Atomic nuclei with a magic number of nucleons have a higher binding energy and are more stable against nuclear decay. The nuclei traditionally used as neutron targets are H, He, B, Li, Gd, U, In, and Ag. Neutron detection technologies have focused on one of five main categories: gas-filled tubes, solid foil-based detectors, liquid scintillators, inorganic scintillators, and solid-state detectors.
Slow Neutron Detectors
Published in Douglas S. McGregor, J. Kenneth Shultis, Radiation Detection, 2020
Douglas S. McGregor, J. Kenneth Shultis
Neutron detectors based on 3He are generally considered a standard for neutron measurements and are widely used in various nuclear industries. However, the natural abundance of 3He is low. The problem is further exacerbated by the dwindling supply of 3H gas,5 which decays by β-particle emission into 3He. Liquid 3He also has unique superfluid properties for ultra-low-temperature physics, thereby creating another demand for this scarce resource. Consequently, 3He gas and detectors are relatively expensive, costing thousands of US dollars per liter at STP.
Enhancement of Fast Neutron Detection in Liquid Scintillator Detectors
Published in Nuclear Technology, 2022
Gang Li, Ghaouti Bentoumi, Liqian Li
Because of 3He supply challenges, the search for alternate efficient and cost-effective neutron detection techniques is an active research area worldwide.1–3 Liquid scintillator detectors are an attractive option owing to a high neutron scattering cross section, excellent neutron-gamma pulse shape discrimination (PSD), and very low cost of the liquid scintillator material. They have been studied for detecting special nuclear materials (SNMs) under various nuclear security scenarios.4–6 Neutron-gamma discrimination is one crucial aspect of all neutron detector designs. Thermal neutron detectors usually use neutron capture reactions [for example, 3He(n,p)3H or 10B(n,α)7Li, etc.], which generate signals much larger than those from gamma-ray Compton scattering; therefore, the neutron-gamma discrimination can be easily achieved by pulse height. However, for fast neutron scintillator detectors, the discrimination usually relies on pulse shape, which is much more complicated and less effective. The neutron detection efficiency of scintillator detectors is therefore severely affected by neutron-gamma discrimination capabilities.
A New Era of Nuclear Criticality Experiments: The First 10 Years of Radiation Test Object Operations at NCERC
Published in Nuclear Science and Engineering, 2021
Jesson Hutchinson, John Bounds, Theresa Cutler, Derek Dinwiddie, Joetta Goda, Travis Grove, David Hayes, George McKenzie, Alexander McSpaden, James Miller, William Myers, Ernesto Andres Ordonez Ferrer, Rene Sanchez, Travis Smith, Katrina Stults, Nicholas Thompson, Jessie Walker
Neutron measurements also have multiple objectives. Systems are used to infer the total neutron emission or dose rate from a configuration. Neutron noise analysis methods are also used, which take advantage of the fact that multiple neutrons can be created from a single fission event at the same time.49,50 Neutron noise methods are performed to infer the system multiplication and/or effective multiplication factor . Neutron imaging is an objective for some measurements. Neutron detector systems generally include proportional counters or scintillators. One system that estimates the neutron emission rate is the Shielded Neutron Assay Probe (SNAP) detector shown in Fig. 4. One example of a He system that is often used for neutron noise measurements is the MC-15 detector (sometimes referred to as the NoMAD detector),14 shown in Fig. 5. An example of an OS system used for neutron noise measurements is shown in Fig. 6.
Measurement of the Gas Velocity in a Water-Air Mixture in CROCUS Using Neutron Noise Techniques
Published in Nuclear Technology, 2020
Mathieu Hursin, Oskari Pakari, Gregory Perret, Pavel Frajtag, Vincent Lamirand, Imre Pázsit, Victor Dykin, Gabor Por, Henrik Nylén, Andreas Pautz
The VOID channel is installed in the north part of the CROCUS reflector, shown in Fig. 4, as close as possible to the fuel in order to benefit from the thermal flux peak in the reflector. Various types of neutron detectors sensitive mostly to thermal neutrons have been used during this work, namely BF3 ionization chambers (ICs) and small and large 235U fission chambers. The experimental setup illustrated in Fig. 4 involves the large fission chambers that led to the successful noise measurements described in Sec. III.C. Various views of the VOID channel as installed in CROCUS are also provided in Fig. 5.