ECAL MPD: geometry and simulation Kulikov, V.V.; Bulychjov, S.A.; Martemianov, M.A. ...
Journal of instrumentation,
09/2020, Letnik:
15, Številka:
9
Journal Article
Recenzirano
New features of the MPD electromagnetic calorimeter of “shashlyk”-type are emphasized. Projective geometry of modules in cylindrical volume and complicated carbon fiber support structure are briefly ...described. Geant4 based simulation programm and main characteristics of the calorimeter are discussed.
The report describes the Monte-Carlo simulation software developed for the projective geometry version of the electromagnetic calorimeter of the MPD detector. The results of software tests and some ...characteristics of the calorimeter are presented.
Experimental data are presented on differential cross sections of the formation of
11
Be,
12
Be, and
12
B isotopes. The isotopes form upon the fragmentation of a carbon beam at 300 MeV/nucleon in the ...FRAGM experiment performed at the multipurpose ITEP−TWAC accelerating complex. The experimental data are compared to predictions made with the binary cascade and quantum molecular dynamic models of ion–ion interaction.
The FRAGM experiment is carried out on the basis of the ITEP–TWAC multipurpose accelerator complex, which generated proton and ion beams for various studies in the field of nuclear physics. A ...technique for identifying fragments in secondary ion beams based on the analysis of correlation distributions over the time of flight and signal amplitude from scintillation detectors is presented. The experimental data are obtained by fragmentation of a carbon beam with energy of 300 MeV per nucleon by scanning the rigidity of the magneto-optical channel with a step of 50 MeV/
c
. Differential cross sections for ion production are obtained using beryllium isotopes as an example. The results are compared with the predictions of the binary cascade model.
In the frame of the GEANT4 toolkit, a numerical simulation of light collection from the tower of the EMC MPD / NICA detector was carried out. The influence of reflective coatings of the scintillator ...surface, the propagation of light in fibers, taking into account their multilayer structure and light reflection from their ends, as well as the effects of joining a fiber bundle with an MPPC photodetector are considered. The temporal forms of the light signal at the MPPC input were obtained taking into account only geometric effects.
The results of searches for nucleon charge-exchange processes in the fragmentation of carbon ions are presented. The respective experimental data were obtained by means of the FRAGM facility at the ...TWAC-ITEP multipurpose accelerator complex with a 300-MeV/nucleon beam incident to a thin beryllium target. The experimental setup used, which was oriented at an angle of 3.5
with respect to the ion beam, possessed a hodoscope system, which ensured an accuracy of 0.4
in momentum measurements. The differential cross sections for the yields of isotopes
Be and
B produced upon single nucleon charge exchange were measured as a function of the fragment momentum. These experimental data were compared with theoretical predictions of two models of ion–ion interactions: the binary cascade (BC) model and the intranuclear cascade (INCL) model. In the above energy range, processes of nucleon charge exchange were measured for the first time.
The differential cross sections for the yields of nuclear fragments at an angle of 3.5◦ in the fragmentation of carbon nuclei with energy 0.95 GeV per nucleon on a beryllium target were measured in ...the FRAGM experiment at the ITEP TWA heavy-ion accelerator. The momentum spectra of fragments were used to test the following four models of ion–ion interactions: BC, INCL++, LAQGSM03.03, and QMD. For light fragments, the slope parameters of the kinetic-energy spectra were obtained in the cumulative region.
In the FRAGM experiment at the heavy-ion accelerator
accumulator complex ITEP
TWA, yields of cumulative charged
mesons have been measured in a fragmentation of carbon ions with the energy of 3.2 ...GeV/nucleon on a beryllium target. The momentum spectra of
mesons cover four orders of the invariant cross section magnitude. They demonstrate the exponential fall with increasing energy. The measured inverse slope parameter is compared with similar measurements in nucleon–nucleus interactions and ion–ion collisions at lower energies. The energy dependence of the ratio of the yields of negative to positive
mesons is presented. This dependence is discussed in a connection with Coulomb and isotopic effects. The obtained data are compared with predictions of several ion–ion interaction models.
The quasifree
γ
→
d
→
π
0
n
(
p
)
photon beam asymmetry,
Σ
, has been measured at photon energies,
E
γ
, from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the ...first time. The data were collected in the A2 hall of the MAMI electron beam facility with the Crystal Ball and TAPS calorimeters covering pion center-of-mass angles from 49
∘
to 148
∘
. In this kinematic region, polarization observables are sensitive to contributions from the
Δ
(
1232
)
and
N
(1440) resonances. The extracted values of
Σ
have been compared to predictions based on partial-wave analyses (PWAs) of the existing pion photoproduction database. Our comparison includes the SAID, MAID and Bonn–Gatchina analyses; while a revised SAID fit, including the new
Σ
measurements, has also been performed. In addition, isospin symmetry is examined as a way to predict
π
0
n
photoproduction observables, based on fits to published data in the channels
π
0
p
,
π
+
n
and
π
-
p
.
The quasifree
photon beam asymmetry,
, has been measured at photon energies,
, from 390 to 610 MeV, corresponding to center of mass energy from 1.271 to 1.424 GeV, for the first time. The data were ...collected in the A2 hall of the MAMI electron beam facility with the Crystal Ball and TAPS calorimeters covering pion center-of-mass angles from 49
to 148
. In this kinematic region, polarization observables are sensitive to contributions from the
and
(1440) resonances. The extracted values of
have been compared to predictions based on partial-wave analyses (PWAs) of the existing pion photoproduction database. Our comparison includes the SAID, MAID and Bonn-Gatchina analyses; while a revised SAID fit, including the new
measurements, has also been performed. In addition, isospin symmetry is examined as a way to predict
photoproduction observables, based on fits to published data in the channels
,
and
.
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