The flux weighted average cross sections 〈σ〉 and cross sections per equivalent photon σq were first measured for the photonuclear multiparticle reactions natSe(γ, xnyp) at end-point bremsstrahlung ...gamma energies ranging from 20 to 80 MeV. The experiments were performed with the beam from the electron linear accelerator LINAC-200 with the use of the γ-activation technique. The bremsstrahlung photon flux was calculated with the program Geant4. The theoretical values of the flux weighted average cross sections 〈σ〉 and the cross sections per equivalent photon σq were calculated using the partial cross section σ(E) computed with the TALYS package code and the combined model of photonuclear reactions.
The HARP Resistive Plate Chamber (RPC) system was designed for time-of-flight measurement in the large-angle acceptance region of the HARP spectrometer. It comprised 46 four-gap glass RPCs covering ...an area of
∼
8
m
2
. The design of the RPCs, their operation, intrinsic properties, and system performance are described. The intrinsic time resolution of the RPCs is better than 130
ps leading to a system time resolution of
∼
175
ps.
Conceptual design report for the LUXE experiment Abramowicz, H.; Acosta, U.; Altarelli, M. ...
The European physical journal. ST, Special topics,
2021, Letnik:
230, Številka:
11
Journal Article
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This Conceptual Design Report describes LUXE (Laser Und XFEL Experiment), an experimental campaign that aims to combine the high-quality and high-energy electron beam of the European XFEL with a ...powerful laser to explore the uncharted terrain of quantum electrodynamics characterised by both high energy and high intensity. We will reach this hitherto inaccessible regime of quantum physics by analysing high-energy electron-photon and photon-photon interactions in the extreme environment provided by an intense laser focus. The physics background and its relevance are presented in the science case which in turn leads to, and justifies, the ensuing plan for all aspects of the experiment: Our choice of experimental parameters allows (i) field strengths to be probed where the coupling to charges becomes non-perturbative and (ii) a precision to be achieved that permits a detailed comparison of the measured data with calculations. In addition, the high photon flux predicted will enable a sensitive search for new physics beyond the Standard Model. The initial phase of the experiment will employ an existing 40 TW laser, whereas the second phase will utilise an upgraded laser power of 350 TW. All expectations regarding the performance of the experimental set-up as well as the expected physics results are based on detailed numerical simulations throughout.
The yields of photonuclear reactions in the 107Ag, 113In, and 115In nuclei have been measured. Monte Carlo simulations have been performed using the Geant4 code, and the results have been compared ...with the experimental ones. The isomeric ratios of the yields in the reactions 107Ag({\gamma},n)106m,gAg and 113In({\gamma},n)112m,gIn have been determined. The cross sections for the reactions 107Ag({\gamma},n)106gAg and 107Ag({\gamma},2n)105Ag at an energy of 20 MeV have been calculated on the basis of the experimental data.
A new design of a detector plane of sub-millimetre thickness for an electromagnetic sampling calorimeter is presented. It is intended to be used in the luminometers LumiCal and BeamCal in future ...linear e
+
e
-
collider experiments. The detector planes were produced utilising novel connectivity scheme technologies. They were installed in a compact prototype of the calorimeter and tested at DESY with an electron beam of energy 1–5 GeV. The performance of a prototype of a compact LumiCal comprising eight detector planes was studied. The effective Molière radius at 5 GeV was determined to be (8.1 ± 0.1 (stat) ± 0.3 (syst)) mm, a value well reproduced by the Monte Carlo (MC) simulation (8.4 ± 0.1) mm. The dependence of the effective Molière radius on the electron energy in the range 1–5 GeV was also studied. Good agreement was obtained between data and MC simulation.
This paper describes an iterative method of per-pixel energy calibration of hybrid pixel detectors with GaAs:Cr sensor and Timepix readout chip. A convolution of precisely measured spectra of ...characteristic X-rays of different metals with the resolution and the efficiency of the pixel detector is used for the calibration. The energy resolution of the detector is also measured during the calibration. The use of per-pixel calibration allows to achieve a good energy resolution of the Timepix detector with GaAs:Cr sensor: 8 and 13% at 60 and 20 keV, respectively.
Investigation of the semiconductor detectors properties under neutron irradiation is very important for their practical application. High-resistivity gallium arsenide detectors (GaAs:Cr) were ...irradiated with various fast neutron fluences in range from 3.9×10n cm−2 to 3.7×1016 cm−2 at the IBR-2 reactor, FLNP, JINR. The neutron fluence was measured by placing silicon planar detectors at the measured points and measuring the 1 MeV (Si) equivalent fast neutron fluence. The charge collection efficiency and the current-voltage characteristics of irradiated detectors were measured, and their degradation after neutron irradiation was compared with the results obtained by irradiation with 21 MeV electrons.
In order to follow relative yields of
Bi(
) reactions, samples of natural bismuth were exposed in LINAC-200 bremsstrahlung beam at four different energies. Activities of eight obtained photonuclear ...reaction products with neutron multiplicity up to (
) were observed. Reaction yields normalized to the
Bi yield were calculated. The measured relative yields of
Bi isotopes were compared with the theoretical evaporation model based on the microscopically calculated level densities and with GEANT4 simulation.
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