scholarly journals Response to Neutrons and γ-rays of Two Liquid Scintillators

2019 ◽  
Vol 6 (2) ◽  
pp. 171-178
Author(s):  
Hector Rene Vega-Carrillo ◽  
Martha Isabel Escalona-Llaguno ◽  
Luis Hernandez-Adame ◽  
Sergio M. Sarmiento-Rosales ◽  
Claudia A. Márquez-Mata ◽  
...  
Keyword(s):  
Neutron Source ◽  
Photon Energy ◽  
Gamma Rays ◽  
Pulse Shape ◽  
Pulse Height ◽  
Scintillation Detectors ◽  
Neutron Detectors ◽  
Multichannel Analyzer ◽  
Γ Rays ◽  
G Company

UltimaGoldTM AB and OptiphaseTrisafe are two liquid scintillators made by Perkin Elmer and EG & G Company respectively. Both are commercially promoted as scintillation detectors for α and β particles. In this work, the responses to γ-rays and neutrons of UltimaGoldTM AB and OptiphaseTriSafe liquid scintillators, without and with reflector, have been measured aiming to use these scintillators as γ-rays and neutron detectors. Responses to γ-rays and neutrons were measured as pulse shape spectra in a multichannel analyzer. Scintillators were exposed to gamma rays produced by 137Cs, 54Mn, 22Na and 60Co sources. The response to neutrons was obtained with a 241AmBe neutron source that was measured to 25 and 50 cm from the scintillators. The pulse height spectra due to gamma rays are shifted to larger channels as the photon energy increases and these responses are different from the response due to neutrons. Thus, UltimaGoldTM AB and OptiphaseTrisafe can be used to detect γ-rays and neutrons.

Gamma rays and high-energy neutrons in the atmosphere

1968 ◽  
Vol 46 (10) ◽  
pp. S1030-S1033 ◽  
Author(s):  
M. V. K. Apparao ◽  
R. R. Daniel ◽  
George Joseph ◽  
G. S. Gokhale ◽  
P. J. Lavakare ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Counting Rate ◽  
Plastic Scintillator ◽  
Pulse Height ◽  
Growth Curves ◽  
High Energy ◽  
Cutoff Rigidity ◽  
Energy Formula ◽  
Γ Rays ◽  
Γ Ray

In continuation of our earlier experiments studying the emission of solar neutrons, we have now developed detector systems which respond to γ rays of energy 1–5 MeV and neutrons of energy [Formula: see text]. The two detectors are almost identical. Each consists of a CsI (Na) crystal (B) of diameter 3.8 cm, completely enclosed in a tapered cylinder of plastic scintillator (A) operated in anticoincidence; the crystals have thicknesses of 2.4 and 1.2 cm respectively. A balloon carrying these detectors was flown on March 16, 1967 over Hyderabad, India (vertical cutoff rigidity 16.9 GV) and floated at a ceiling altitude of 6.0 mb for 1 hour. In addition to γ-ray and neutron events (AB), events A and AB were also continuously monitored throughout the flight. Pulses corresponding to 1–5 MeV in the 2.4-cm crystal (γ rays) and 6–40 MeV in the 1.2-cm crystal (high-energy neutrons) were analyzed by a 64-channel pulse-height analyzer. On the basis of the pulse-height distributions and γ-ray efficiencies in the two crystals, we attribute events of 1–5 MeV energy from the thicker crystal to γ rays and those > 10 MeV in energy from the thinner one to stars produced by high-energy neutrons [Formula: see text] in the crystal. Atmospheric growth curves for γ rays and neutrons have been obtained; these growth curves as well as those for events A and AB show the normal features of the Pfotzer maximum, steady decreases up to the ceiling altitude, and a constant counting rate at ceiling. The atmospheric counting rates at ceiling altitude give for γ rays of energy 1–5 MeV a flux of ~1 photon per cm2 s and for neutrons of energy [Formula: see text] a flux of ~0.1 neutron per cm2 s. No evidence for a solar component in either channel was found.

scholarly journals Neutron detection performance of gallium nitride based semiconductors

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Chuanle Zhou ◽  
Andrew G. Melton ◽  
Eric Burgett ◽  
Nolan Hertel ◽  
Ian T. Ferguson
Keyword(s):  
Gallium Nitride ◽  
Thermal Neutron ◽  
Particle Physics ◽  
Nuclear Power ◽  
Pulse Height ◽  
Neutron Cross Section ◽  
Neutron Detection ◽  
Rare Earth Doping ◽  
Scintillation Detectors ◽  
Neutron Detectors

AbstractNeutron detection is crucial for particle physics experiments, nuclear power, space and international security. Solid state neutron detectors are of great interest due to their superior mechanical robustness, smaller size and lower voltage operation compared to gas detectors. Gallium nitride (GaN), a mature wide bandgap optoelectronic and electronic semiconductor, is attracting research interest for neutron detection due to its radiation hardness and thermal stability. This work investigated thermal neutron scintillation detectors composed of GaN thin films with and without conversion layers or rare-earth doping. Intrinsic GaN-based neutron scintillators are demonstrated via the intrinsic 14N(n, p) reaction, which has a small thermal neutron cross-section at low neutron energies, but is comparable to other reactions at high neutron energies (>1 MeV). Gamma discrimination is shown to be possible with pulse-height in intrinsic GaN-based scintillation detectors. Additionally, GaN-based scintillation detector with a 6LiF neutron conversion layer and Gd-doped GaN detector are compared with intrinsic GaN detectors. These results indicate GaN scintillator is a suitable candidate neutron detector in high-flux applications.

Solar Flare Energetic Neutral Emission Measurements in the Project Coronas-I

1994 ◽  
Vol 144 ◽  
pp. 635-639
Author(s):  
J. Baláž ◽  
A. V. Dmitriev ◽  
M. A. Kovalevskaya ◽  
K. Kudela ◽  
S. N. Kuznetsov ◽  
...  
Keyword(s):  
Solar Flare ◽  
Energy Range ◽  
Gamma Rays ◽  
Pulse Shape ◽  
Gamma Ray ◽  
Pulse Shape Discrimination ◽  
Shape Discrimination ◽  
Solar Neutron ◽  
Low Altitude

AbstractThe experiment SONG (SOlar Neutron and Gamma rays) for the low altitude satellite CORONAS-I is described. The instrument is capable to provide gamma-ray line and continuum detection in the energy range 0.1 – 100 MeV as well as detection of neutrons with energies above 30 MeV. As a by-product, the electrons in the range 11 – 108 MeV will be measured too. The pulse shape discrimination technique (PSD) is used.

scholarly journals The internal conversion of gamma-rays.—Part II

1928 ◽  
Vol 121 (787) ◽  
pp. 447-456
Keyword(s):  
Magnetic Field ◽  
Quantum Mechanics ◽  
Wave Equation ◽  
Gamma Rays ◽  
Internal Conversion ◽  
Scalar Potential ◽  
X Ray ◽  
Electro Magnetic Field ◽  
Γ Rays ◽  
Electro Magnetic

In a previous paper the absorption of γ-rays in the K-X-ray levels of the atom in which they are emitted was calculated according to the Quantum Mechanics, supposing the γ-rays to be emitted from a doublet of moment f ( t ) at the centre of the atom. The non-relativity wave equation derived from the relativity wave equation for an electron of charge — ε moving in an electro-magnetic field of vector potential K and scalar potential V is h 2 ∇ 2 ϕ + 2μ ( ih ∂/∂ t + εV + ih ε/μ c (K. grad)) ϕ = 0. (1) Suppose, however, that K involves the space co-ordinates. Then, (K. grad) ϕ ≠ (grad . K) ϕ , and the expression (K . grad) ϕ is not Hermitic. Equation (1) cannot therefore be the correct non-relativity wave equation for a single electron in an electron agnetic field, and we must substitute h 2 ∇ 2 ϕ + 2μ ( ih ∂/∂ t + εV) ϕ + ih ε/ c ((K. grad) ϕ + (grad. K) ϕ ) = 0. (2)

THE DECAY OF Pm149

1960 ◽  
Vol 38 (12) ◽  
pp. 1577-1585 ◽  
Author(s):  
Agda Artna ◽  
Margaret E. Law
Keyword(s):  
High Resolution ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Conversion Coefficient ◽  
Beta Spectrum ◽  
Multichannel Analyzer ◽  
Coincidence Spectrometer ◽  
Beta Spectrometer ◽  
Beta Group

The 52.8-hour activity of Pm149 has been investigated using a high resolution beta spectrometer, a lens type coincidence spectrometer, and a scintillation spectrometer in conjunction with a multichannel analyzer. The beta spectrum was found to consist of two groups with maximum energies of 1.072 ± 0.002 Mev and 0.786 ± 0.004 Mev, and intensities of 97.1 ± 0.4% and 2.9 ± 0.4% respectively. A gamma ray of energy 285.7 ± 0.3 kev was found to be in coincidence with the 0.786-Mev beta group. No other gamma rays with intensities greater than 0.1% were found. The K conversion coefficient for the 286-kev transition was measured to be 0.075 ± 0.008. This together with the values of 6.5 ± 0.7 and 4 ± 1 obtained for the K/L and L/M conversion ratios respectively indicate that this transition is M1 in character with less than 10% E2 admixture.

The Feasibility Research for Detecting the Nitrogen Content in Sewage with NIPGA Method

2014 ◽  
Vol 602-605 ◽  
pp. 2445-2448
Author(s):  
Fu Quan Jia ◽  
Zhu Jun Tian
Keyword(s):  
Nitrogen Content ◽  
Neutron Source ◽  
Total Nitrogen ◽  
Gamma Rays ◽  
Neutron Generator ◽  
Limit Of Detection ◽  
Total Nitrogen Content ◽  
Feasibility Research ◽  
Type Water

NIPGA technology is used in order to detect the total nitrogen content in sewage quickly. D-D neutron generator is used as the neutron source and BGO detector is used to detect gamma rays of nitrogen. The simulated result of MCNP shows the nitrogen’s limit of detection is 0.2 mg/L and the total nitrogen in V-type water can be detected. So this method can be used to detect the total nitrogen content in sewage quickly.

scholarly journals THERMOCOAX rhodium SPND sensitivity dispersion and validation of the sensitivity calculation model

2020 ◽  
Vol 225 ◽  
pp. 04015
Author(s):  
L. Vermeeren ◽  
W. Leysen ◽  
L. Pichon ◽  
V. Salou ◽  
G. Helleux
Keyword(s):  
Gamma Rays ◽  
Neutron Capture ◽  
Characteristic Time ◽  
Thermal Neutron Flux ◽  
Calculation Model ◽  
Delayed Response ◽  
Neutron Detectors ◽  
Recorded Data ◽  
Self Powered ◽  
Beta Emission

This paper describes the neutron irradiation tests of 7 THERMOCOAX Self-Powered Neutron detectors (SPNDs) in the BR1 reactor at SCK•CEN. The SPNDs were fabricated according to the same specifications, but from different fabrication batches. The SPND signals were recorded during stepwise power-up of the reactor, proving the linearity of the SPND response within a wide thermal neutron flux range: from as low as 0.8·109 n/(cm2) to 2.6·1011 n/(cm2s). Intercomparison of the SPND signals shows a very small spread, confirming the repeatability of the THERMOCOAX fabrication processes. The overall neutron sensitivities of the seven SPNDs agreed within a 1% margin. The experimental data were analyzed in terms of prompt and various delayed responses. Prompt contributions to the signal are due to external gamma induced processes and to processes involving gamma rays emitted instantaneously upon neutron capture. The main contribution in a rhodium SPND is due to activation of the rhodium emitter and beta emission during decay of the activated rhodium and leads to a delayed response with a characteristic time of a few minutes. Activation and subsequent beta decay in other materials present in the SPND lead to additional minor delayed signal contributions. The partial SPND sensitivities due to all these processes were calculated using an MCNPX based model and were compared with experimental sensitivities based on the recorded data. The results were in fair agreement; for the overall SPND neutron sensitivity an agreement within a 1% margin was achieved.

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