An ISPA-camera for gamma rays with improved energy resolution

1997 ◽  
Vol 44 (5) ◽  
pp. 1747-1752 ◽  
Author(s):  
D. Puertolas ◽  
D. Piedigrossi ◽  
H. Leutz ◽  
T. Gys ◽  
F. De Notaristefani ◽  
...  
Keyword(s):  
Energy Resolution ◽  
Gamma Rays

TEST OF THE UNACTIVATED CALCIUM FLUORIDE CRYSTAL FOR USE AS A SCINTILLATION DETECTOR IN Ca48 DOUBLE BETA DECAY EXPERIMENT

1989 ◽  
Vol 04 (03) ◽  
pp. 213-216 ◽  
Author(s):  
WEIHUA TIAN ◽  
KE YOU ◽  
YUCAN ZHU ◽  
WENHENG ZHAO ◽  
ZHIPENG ZHENG ◽  
...  
Keyword(s):  
Beta Decay ◽  
Energy Resolution ◽  
Gamma Rays ◽  
Particle Energy ◽  
Double Beta Decay ◽  
Test Results ◽  
Energy Response ◽  
Scintillation Crystal ◽  
Response Range ◽  
Double Beta Decay Experiment

The test results of the properties of the unactivated CaF 2 scintillation crystal detector is reported. The energy response of a small size CaF 2 crystal and a large CaF 2 crystal detector, which will be used in the Ca 48 Double Beta Decay (DBD) experiment, to gamma rays and an electron beam from 6 to 10 MeV was tested. The results indicate that the linear energy response range can be extended to 10 MeV for the large CaF 2 detector. Meanwhile, the relation of the energy resolution to the incident particle energy is represented by E−1/2 (MeV) . (It is anticipated that the energy resolution at 4.27 MeV will be about 9%.)

Energy Resolution and Non-proportionality of Scintillation Detectors

2007 ◽  
Vol 1038 ◽  
Author(s):  
Marek Moszynski
Keyword(s):  
Liquid Nitrogen ◽  
Energy Resolution ◽  
Gamma Rays ◽  
Avalanche Photodiodes ◽  
Intrinsic Property ◽  
Liquid Nitrogen Temperature ◽  
Scintillation Detectors ◽  
Crucial Importance ◽  
Light Pulses ◽  
Intrinsic Energy

AbstractThe limitation of energy resolution of scintillation detectors are discussed with a special emphasis on non-proportionality response of scintillators to gamma rays and electrons, which is of crucial importance to an intrinsic energy resolution of the crystals. Examples of the study carried out with different crystals and particularly those of tests of undoped NaI and CsI at liquid nitrogen temperature with the light readout by avalanche photodiodes are presented suggesting strongly that the non-proportionality of the halide crystals are not their intrinsic property. Moreover, the influence of slow components of the light pulses on energy resolution and non-proportionality are discussed.

MGNS experiment science investigations during BepiColombo cruise

2020 ◽  
Author(s):  
Alexander Kozyrev ◽  
Maxim Litvak ◽  
Anton Sanin ◽  
Alexey Malakhov ◽  
Igor Mitrofanov ◽  
...  
Keyword(s):  
Energy Range ◽  
Energy Resolution ◽  
Gamma Rays ◽  
Time Resolution ◽  
Solar Flares ◽  
Gamma Ray ◽  
Galactic Cosmic Rays ◽  
Wide Energy Range ◽  
Gamma Ray Emission ◽  
Mars Odyssey

<p>The Mercurian Gamma-ray and Neutron Spectrometer (MGNS) is a scientific instrument developed to study the elementary composition of the Mercury’s sub-surface by measurements of neutron and gamma-ray emission of the planet. MGNS measures neutron fluxes in a wide energy range from thermal energy up to 10 MeV and gamma-rays in the energy range of 300 keV up to 10 MeV with the energy resolution of 5% FWHM at 662 keV and of 2% at 8 MeV. The innovative crystal of CeBr3 is used for getting such a good energy resolution for a scintillation detector of gamma-rays.</p> <p>During the BC long cruise to Mercury, it is planned that the MGNS instrument will operate practically continuously to perform measurements of neutrons and gamma-ray fluxes for achieving two main goals of investigations.</p> <p>The first goal is monitoring of the local radiation background of the prompt spacecraft emission due to bombardment by energetic particles of Galactic Cosmic Rays. This data will be taken into account at the mapping phase of the mission on the orbit around Mercury. Detailed knowledge of the spacecraft background radiation during the cruise will help to derive the data for neutron and gamma-ray emission of the planet at the mapping stage of the mission because many elements, like Mg, Na, O and others, the abundance of which at the uppermost layer of the planet is studied, are also present in the material of the spacecraft. Indeed, the nuclear lines of Al, Mg and O are well-pronounced in the spectrum, which are also expected to be detectable in the gamma-ray spectrum of the Mercury emission.</p> <p>The second goal of MGNS cruise operations is the participation in the Inter Planetary Network (IPN) program for the localization of sources of Gamma-Ray Bursts in the sky. In fact, the localization accuracy by the interplanetary triangulation technique is inversely proportional to the distance between the spacecrafts that jointly detected a GRB. Before the launch of BepiColombo, the IPN network included a group of spacecrafts in the near-to-Earth orbit (e.g. Konus-Wind, Fermi-GBM, INTEGRAL, Insight-HXMT) and the Mars Odyssey spacecraft on the orbit around Mars. Now, MGNS provides another interplanetary location, potentially increasing the accuracy of GRBs localization. During the first 13 months of continuous operation, MGNS detected 24 GRB's. Pre-set value of time resolution for continuous measurements of profiles of GRBs is 20 seconds. Since of November 14, 2019, the BC Mission Operation Centre has allocated downlink resources to run MGNS continuously in a 1 sec time resolution for GRB measurements. The GRB detection rate, based on data with a time resolution of 1 sec is about 2-3 GRB's per month.</p> <p>Gamma-rays of solar flares are also detectable by MGNS. Solar flares are nonstationary and anisotropic processes and the ability to observe them from different directions in the Solar system is crucial for further understanding their developments and propagation, as it was demonstrated in the case of HEND instrument on board Mars Odyssey. The Sun cycle is presently around its minimum, and MGNS has not detected any solar events during its first 7 months of the cruise, but the flight to Mercury is long enough and many future flares are expected to be detected.</p> <p>The MGNS instrument will also perform special sessions of measurements during flybys of Earth, Venus and Mercury with the objective to measure neutron and gamma-ray albedo of the upper atmosphere of Earth and Venus and of the surface of Mercury. Another objective is to test the computational model of the local background of the spacecraft using the data measured at different orbital phases of flyby trajectories. The low altitude flybys (such as the 700 km flyby for Venus and three 200 km flybys for Mercury) would be the most useful for such tests being BC maximally shadowed for cosmic radiation by the actual planet. Neutron and gamma-ray measurements during Earth flybys enable investigation of interaction between solar wind and Earth environments as well as studies of spacecraft neutron and gamma-ray background upon its passage through the Earth's radiation belts.</p>

A Theoretical and Laboratory Evaluation of Carbon Logging - Laboratory Evaluation

1971 ◽  
Vol 11 (02) ◽  
pp. 129-138 ◽  
Author(s):  
B.L. Lawson ◽  
C.F. Cook ◽  
J.D. Owen
Keyword(s):  
Single Crystal ◽  
Energy Resolution ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Detector System ◽  
Laboratory Evaluation ◽  
Gamma Detector ◽  
Carbon Detection ◽  
Logging Tool ◽  
Compton Background

Abstract Results we presented from a laboratory experimental evaluation of a carbon well-logging tool based on the detection of the 4.43-MeV gamma rays produced by the inelastic scattering of 14-MeV neutrons. The success of a carbon logging tool is dependent primarily upon the gamma-ray detection scheme used, which in this investigation is a two-crystal pair spectrometer. Using such a device in a simulated reservoir with and without casing and a cement annulus, semiquantitative detection of carbon was accomplished for a fluid-filled packed sand of 35-percent porosity. Analysis of the spectral results show that the log would be sensitive to lithology, saturation and porosity as well as carbon. With the resolution of this particular gamma-ray detector scheme, the presence of the casing using seen, but did not interfere with the carbon signal. Likewise the 1-in. annulus of concrete had no effect on the carbon detection. Comparison of our results with those previously published show that the oxygen and silicon interference encountered i, other proposed logging schemes is eliminated by the two-crystal pair spectrometer. As presently envisaged, between 5 to 10 minutes per pay zone to be evaluated is required to per pay zone to be evaluated is required to accumulate raw data. However, the growth potential offered by the new Ge(Li) gamma-ray counters may well remove this restriction. Introduction Theoretical results presented in Ref. 1 have indicated that liquid hydrocarbons should be detectable in noncarbonaceous reservoirs. Although the interference problem posed by energy degraded gamma rays from omnipresent oxygen is severe, it is not severe enough to prohibit detection of hydrocarbons by nuclear means. The theoretical data also showed thermal neutron effects caused by energy degradation of gamma rays from thermal capture in silicon, chlorine and iron could be eliminated by proper choice of a neutron source gamma detector gating scheme. Indeed, this has been demonstrated experimentally. The crux of the hydrocarbon detection problem lies with finding a gamma detector system with sufficient resolution to pick out 4.43-MeV gamma rays (carbon) from the background provided by oxygen. Previous investigations have shown that single NaI(T1) crystal detectors did not have sufficient energy resolution to accomplish the task. However, energy resolution is not the whole answer when it comes to extracting a monoenergetic signal from a continuum background. In addition to the interfering gamma rays produced through Compton collisions external to the detector system, there is an in-crystal Compton background in single-crystal spectrometry. The second source of interference arises because gamma rays entering the crystal at energies higher than the discrete energy of interest will produce Compton collisions within the crystal generating electrons that have precisely the same energy as that of the "desired signal". This second source of interference significantly reduces the carbon sensitivity of a single-crystal detector. Hence, elimination of the in-crystal background from oxygen produced gamma rays would go far in improving the in-situ carbon detection picture. In searching for an acceptable detector system, this point was kept foremost in mind. It was known a three-crystal pair spectrometer would virtually eliminate the in-crystal Compton background, but limitations imposed by borehole tool size ruled out its use. However, from studying the working principle of this device the concept of the principle of this device the concept of the two-crystal pair spectrometer emerged. A description of such a device was later found in Ref. 4 although no evidence has been found that such a device has been used to record spectra in a borehole or simulated borehole environment. This report presents experimental results obtained with such a presents experimental results obtained with such a two-crystal spectrometer in various simulated reservoir conditions. SPEJ P. 129

Luminescence and Scintillation Properties of Ce-Doped LYSO and YSO Crystals

2011 ◽  
Vol 199-200 ◽  
pp. 1796-1803 ◽  
Author(s):  
Chalerm Wanarak ◽  
Weerapong Chewpraditkul ◽  
Akapong Phunpueok ◽  
Jakrapong Kaewkhao
Keyword(s):  
Rare Earth ◽  
Energy Resolution ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Light Yield ◽  
Mass Attenuation Coefficient ◽  
Significant Progress ◽  
Transmission Method ◽  
Intrinsic Resolution ◽  
Γ Ray

The luminescence and gamma-ray detection properties of the new cerium-doped rare-earth scintillator lutetium-yttrium oxyorthosilicate ( Lu1.95Y0.05SiO5:Ce, LYSO:Ce) were investigated and compared to those of cerium-doped yttrium oxyorthosilicate ( Y2SiO5:Ce, YSO:Ce) crystal. The light yield and energy resolution were measured using photomultiplier tube (PMT) readout. The non-proportionality of the light yield and energy resolution versus γ-ray energy were measured and the intrinsic resolution of the crystals was calculated. In spite of significant progress in light yield and luminescence properties, the energy resolution of LYSO:Ce appears to still suffer from an excess variance in the number of scintillation photons. The mass attenuation coefficient of LYSO:Ce and YSO:Ce for 662 keV gamma rays was also measured by transmission method and compared with the theoretical values calculated by WinXCom program.

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