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Preprints and Communications
 Here
you can find JINR preprints and communications in pdf format starting
from 1999.
File size is given in bytes in round brackets.
| 2022 |
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P3-2022-13 (496.940)
Dubois M. et al.
Enhanced Directional Extraction of Very Cold Neutrons Using a Diamond
Nanoparticle Powder Reflector
For more than a decade, Detonation NanoDiamond (DND) powders have been
actively studied as a material for efficient reflectors of Very Cold
Neutrons (VCNs) and Cold Neutrons (CNs). During this time, the storage of
VCNs in traps with walls made of DND powder and the quasi-specular
reflection of CNs from layers of DND powder have been experimentally
demonstrated. The quality of DND powder has been improved by reducing the
fraction of impurities causing neutron losses, as well as by choosing the
powder parameters that correspond to the most efficient reflection of
neutrons. Methods for calculating the transport of neutrons in real powders
have been developed. In this work, we experimentally demonstrate the
possibility of shaping a VCN beam using a reflector made of fluorinated DND
(F-DND) powder. With respect to the flux from an isotropic source located at
the bottom of the reflector cavity, the gain in the VCN flux density along
the beam axis is ∼ 10 for the neutron velocities of 57 m/s and
75 m/s. The gain in the total flux at the exit from the reflector cavity is
∼ 14 for the fastest VCNs from the interval 46—92 m/s
and increases with decreasing VCN velocity, reaching ∼ 33 for
the slowest VCNs.
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E7-2022-12 (413.769)
Isaev A. V. et al.
Spontaneous Fission of 246Fm
An experiment on the study of the 246Fm spontaneous fission was conducted using the SHELS separator. The isotope was synthesized in the complete
fusion reaction of 40Ar beam ions and 208Pb target nuclei.
The neutron yields of 246Fm spontaneous fission (¯ν = 3,79±0,30, σ2nu = 2,1) were obtained using the SFiNx detector system.
The multiplicity distribution of emitted prompt neutrons was restored using the Tikhonov method of statistical regularisation (¯νr = 3,79 ± 0,20, σ2νr= 2,8).
The spontaneous fission branching ratio (bSF = 0,061 ± 0,005) and the half-life (T1/2 = 1,50+0,08-0,07 s) of the isotope were determined.
The experimental data were compared with scission point model predictions. Excellent convergence was observed in the average number of neutrons per spontaneous fission process.
However, the forms of the experimental and model prompt neutron multiplicity distributions differ significantly.
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Ð9-2022-10 (927.586)
Teterev Yu. G. et al.
Estimation of the Yield and Angular Distribution of Neutrons for
Calculating the Biological Protection of Reconstructed Heavy Ion
Accelerators with Energies from 1 to 6 MeV/nucleon
Simple analytical formulas are presented for the operational estimation of
the yield and angular distribution of neutrons, which are necessary for
calculating the biological protection of heavy ion accelerators with
energies from 1 to 6 MeV/nucleon. The results of the calculation were
compared with the results of calculations using the LIZE++ and FLUKA
programs and with the available experimental data in the literature. As a
result of the comparisons, it can be argued that the proposed method for
calculating the yield and angular distribution of neutrons from thick
targets can be used to quickly assess the necessary biological protection of
heavy ion accelerators under construction and reconstruction with energies
from 1 to 6 MeV/nucleon. The deviation of the results of these calculations from
the more accurate ones does not exceed a factor of two, which is comparable
with the results of deviations in the calculation of biological shielding
associated with a certain variety of spectra of produced neutrons and
deviations in the protective properties of the materials used or their
thickness.
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P10-2022-5 (496.940)
Kirilov A.S., Murashkevich S.M.
Adaptation of the Sonix+ Software Package to Work
with DAQ Controllers DeLiDAQ-2 and Digitizer N6730 by CAEN
Before the use of DeLiDAQ-2 controllers and Digitizer N6730 on the IBR-2
reactor instruments, the main form of DAQ output data was spectral
distributions of intensities in matrix form, which, in particular, was used
in the Sonix$+$ software package for online visualization. Due to the fact
that output data from considered controllers are available only in the
events list form, the construction of spectral distributions (histogramming)
must be done by programs.The work is devoted to adaptation of the complex
for use of the controllers specified, algorithms of data histogramming for
them, as well as to tests results carried out at the GRAINS instrument (beam 10 of the IBR-2) in October 2021 consideration.
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P10-2022-4 (496.940)
Kirilov A. S., Truntova L. A.
Enhancement of Experiment Control in the Sonix+ Software Package
The work is devoted to enhancing the Sonix+ software package at the IBR-2
instruments to minimize the loss of measurement time when including
mathematical operations (summing matrices, building spectral distributions
of intensity based on data from the list of events, etc.) directly in the
experimental procedure in the Python language (script). For this purpose,
the execution of all such operations was separated from the main script into
one or more background scripts. A special device class has been added to the
complex structure to execute background scripts. Besides this, the
checkpoint mechanism previously used to connect the user interface with the
script has been replaced by a new one — based on Python language decorators
and context managers. This significantly simplified the script, improved its
reliability, and reduced the time of its development or modification.
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2022-2 (20.032.428)
Brief Review of Topmost Scientific Results Obtained in 2021 at the Joint Institute for Nuclear Research
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Ð9-2022-1 (2.030.431)
Kozlov O. S. et al.
Actual Tasks of Beam Dynamics Analysis in the NICA Collider
The NICA project is under development at the Joint Institute for Nuclear Research
(Dubna). The accelerator complex is in the stage of step-by-step assembly and commissioning. The complex consists of two superconducting synchrotrons and
a superconducting ion collider. Numerous studies of beam dynamics, performed
at the design stage, formed the basis of R&D of the collider systems.
Most part of tasks was done in detail and totally completed. However, a
number of tasks are not finished and actual to date. Some of them, being
fundamental, need detailed analysis using
three-dimensional particle tracing with taking into account all the main
physical effects and nonlinearities of electromagnetic fields of the
structure. Key task in the NICA collider is study of collective phenomena,
to which this work is mainly devoted. The paper describes the current status of
numerical and analytical calculations of beam stability in the NICA collider
and possible plans of solution of noncompleted tasks.
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