In this study, we present depth-dose profiles measured with a water phantom at the boron neutron-capture therapy (BNCT) facility at Budker Institute of Nuclear Physics (BINP). The presented results ...demonstrate that the proposed design of radiation detector with an optical fiber readout, which includes three different sensors (the first based on a plastic scintillator enriched with boron, the second based on a simple plastic scintillator, and the third having no scintillator at all), enables measurement of neutron flux, as well as estimations of the dose induced by gamma rays. The results of simulations with the GEANT4 package demonstrated good agreement with the experimental data and can be used for further system improvement.
Abstract
For the first time observed that at the initial stage of a high-current discharge, a low-divergence short (<2 ns) electromagnetic pulse is formed over a ferrite surface. The 50% part of the ...energy spectrum of this pulse lies in the region of sufficiently hard x-ray radiation (hν > 1 keV) with an energy of 0.6 mJ and an average power of 0.3 MW. The radiation propagates parallel to the surface in the anode direction with the angle divergence <2°. The high directionality of the radiation in absence of the aperture-limiting devices for the radiation beam and the quadratic dependence of the spatial radiation energy flux density on the length of working part of the ferrite prism points to the coherent nature of the observed radiation. A possible generation mechanism of the radiation is proposed. It is based on the short-lived magnetization of the ferrite plots by a high-power electromagnetic pulse and the subsequent coherent interference of unit waves irradiated by these plots.
In recent years, we could observe significant progress in the design of accelerator-based neutron sources for boron neutron capture therapy (BNCT) . An important component of such systems is a ...neutron-sensitive detector system capable of monitoring the patient dose at significantly higher particle rates than in nuclear reactor systems. Simultaneous operation of two detectors: the first, sensitive to gammas, and the second, sensitive to gammas and neutrons, enables more accurate extraction of the neutron contribution. Scintillator-based detectors with fiber-optic readout have several important advantages. They are compact and have high speed, and additionally, the readout electronics can be placed far from the neutron source. In this research, we evaluated the main parameters of two plastic scintillators that are produced in Russia and meet this goal: SC-301 and boron-enriched SC-331. The resulting light yield of SC-331 was 8600 photons/MeV, and for SC-301 it was approximately 25% higher. Therefore, these scintillators are promising candidates for future detector systems.
In the present report, we summarize the results of our efforts to create an X-ray counting detector based on silicon photomultipliers (SiPMs) for digital scanning radiography with a sub-millimeter ...resolution. To realize this detector, we produced samples of pixelated scintillators with a pitch of 250μm using the laser ablation technology. To measure real detector parameters, we have built a detector prototype based on a 32-channel Omega EASIROC front-end chip and a linear SiPM array. The results obtained in this study demonstrated the possibility of creating such high-resolution X-ray detectors.
Measurement of Γee(J/ψ) with KEDR detector Anashin, V. V; Aulchenko, V. M; Baldin, E. M ...
The journal of high energy physics,
05/2018, Letnik:
2018, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A
bstract
The product of the electronic width of the
J/ψ
meson and the branching fractions of its decay to hadrons and electrons has been measured using the KEDR detector at the VEPP-4M
e
+
e
−
...collider. The obtained values are
Γ
e
e
J
/
ψ
=
5.550
±
0.056
±
0.089
keV
,
Γ
e
e
J
/
ψ
·
ℬ
hadrons
J
/
ψ
=
4.884
±
0.048
±
0.078
keV
,
Γ
e
e
J
/
ψ
·
ℬ
e
e
J
/
ψ
=
0.3331
±
0.0066
±
0.0040
keV
.
The uncertainties shown are statistical and systematic, respectively. Using the result presented and the world-average value of the electronic branching fraction, one obtains the total width of the
J/ψ
meson:
Γ
=
92.94
±
1.83
keV
.
These results are consistent with the previous experiments.
Antioxidant cytoprotective properties of mexidol have been studied under the influence of argon and helium gas-discharge cold plasma of atmospheric pressure on
Paramecium caudatum
cell culture. It ...has been shown that mexidol exhibits strong antioxidant properties and practically completely eliminates the negative effects of oxidative stress, retaining almost 100% of the initial number of cells. The data obtained demonstrate a wide range of behavioral responses of cells of
Paramecium caudatum
, which confirms their practical value as model objects for pharmacological and toxicological studies, and the use of gas-discharge cold plasma makes it possible to exclude the direct oxidative effect of hydrogen peroxide (the standard model of oxidative stress) on the studied drugs and to increase the reliability of toxicological studies.
A simple macroscopic method for detection of current sheet disruptions and determination of the width of metastable sheets is proposed based on the measurements of magnetic fields at the external ...surface of the vacuum chamber. This contactless diagnostic method does not affect the plasma processes in the current sheet and allows one to increase the signal-to-noise ratio. Such changes will allow us to relatively quickly determine the conditions of current sheet development under which sheet disruptions are most probable.
The progress in the design of new accelerator-based neutron sources for boron neutron capture therapy (BNCT) generated new requirements to the detector systems to monitor the particle flux during the ...irradiation of patients. In the current research, we evaluated basic parameters of a twin scintillator-over-fiber system with a silicon photo-multiplier readout based on boron-enriched and boron-free plastic scintillators. The presented results showed that the proposed system could be used for monitoring of neutron flux, and the designed detector system demonstrated good linearity, up to ∼2 mA, limited by accelerator specifications at that time.
Abstract
Spatial properties of the radiation induced by a ferrite surface flashover supported by a 300 kV and ∼1 ns rise time pulsed voltage source were studied. Peak value and rise time were ...obtained for the discharge current.
PDF
