The aim of the present study is to evaluate a gamma probe with active shielding by using GEANT4 simulation framework. We used BGO scintillators both for gamma detection and active shielding from a ...point radioactive source, namely 140 keV gammas from
99
m
Tc
. All scintillators were coupled to the silicon photomultipliers with an active area of
3
×
3
mm
2
. The response of the gamma probe to radiation was simulated using the optical photon transportation available in the GEANT4 package. We used the simulation results to determine the sensitivity, spatial and angular resolution, and shielding efficiencies in the air and scattering medium for the proposed gamma probe model according to NEMA NU 3-2004 standards. The ability of the probe to find the direction of emission was also evaluated. The sensitivity of the probe was found between 1262 - 42284 cps/MBq in the scattering medium based on two scenarios based on active shielding use. In terms of FWHM, the spatial resolution in scattering medium at 30 mm source-to-probe distance was 31 mm and the angular resolution at the same distance was
59
∘
. The shielding effectiveness of the probe was in the range of 89.90 ±
0.65
%
and 97.20 ±
0.19
%
. The emission directions of gammas were found with an error of less than 8°.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this study, we investigated the impact of chemical etching on the light output and energy resolution of LYSO scintillators using simple, affordable laboratory equipment. We found that etching with ...phosphoric acid at temperatures between 180 °C and 190 °C improved the light output and energy resolution compared to mechanically polished crystals, even after minimal etching times. Our results show that with 7.5 min of chemical etching, the light output increase rate is 45.7%, and the relative energy resolution improvement is 12%.
•Light output and energy resolution measured for different surface treatments of LYSO scintillators.•A low-cost chemical polishing setup presented, in which multiple scintillators can be polished simultaneously.•Optimum etching time for ideal surface condition determined.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We present a conceptual sampling electromagnetic calorimeter based on secondary electron emission process. The secondary electron emission process was implemented in Geant4 as a user physics class, ...which accurately reproduces the energy spectrum and yield of secondary electrons for thin metals. The simulation results for the response linearity and energy resolution are compared with that of a scintillation calorimeter. The response and energy resolution of the calorimeter were obtained for electron energies up to 50 GeV . The response linearity to electromagnetic showers is to within 1.5%, whereas the energy resolution is σ/E=(44%)GeV1/2/ E for 2.5 cm sampling of iron absorber.
We present updated results from a simulation study of a conceptual sampling electromagnetic calorimeter based on secondary electron emission process. We implemented the secondary electron emission ...process in Geant4 as a user physics list and produced the energy spectrum and yield of secondary electrons. The energy resolution of the SEE calorimeter was σ/E=(41%)GeV1/2/ E and the response linearity to electromagnetic showers was to within 1.5%. The simulation results were also compared with a traditional scintillator calorimeter.
This paper reports on the commissioning and first running experience of the CMS Zero Degree Calorimeters during December 2009. All channels worked correctly. The ZDCs were timed into the data ...acquisition system using beam splash events. These data also allowed us to make a first estimate of channel-by-channel variations in gain.
The quartz plate calorimeters are considered as hadronic calorimeter options for upgrading Large Hadron Collider experiments. Previous studies have shown that quartz can resist up to 12 MGy of proton ...irradiation. Using uniformly distributed wavelength shifting fibers embedded the quartz plates are shown to solve the problem of low visible light production on Cherenkov process. Here, we report the performance tests of a 20-layer quartz plate calorimeter prototype, which is constructed with this approach. The calorimeter prototype was tested at CERN H2 area in hadronic and electromagnetic configuration, at various energies of pion and electron beams. We report the beam test and simulation results of this prototype, we also discuss future improvement directions on manufacturing radiation hard wavelength shifting fibers for this type of hadronic calorimeter design.
In this work we analyzed the particle creation process of spin-1/2 particles by considering a simple cosmological model, a two-dimensional de Sitter space–time. We choose two different charts, the ...static and global chart, on de Sitter space–time. We solved the Dirac equation for these two charts and then used Bogoliubov coefficients to relate vacuum states in the asymptotic regions of gravitational backgrounds. By using the Bogoliubov transformation technique we compute the density of particles created.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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