A simple analytical formulas for estimation of the yield and angular distribution of neutrons from thick targets would be useful for calculating the biological protection of heavy ion accelerators ...with energy (1–6) MeV/nucleon. The results of the calculation with this formulas were compared with those obtained using the LISE++ and FLUKA programs as well as with the available experimental data. As a result, it can be stated that the proposed calculation method can be used for quick assessment. The deviation of the results of such calculations from more accurate ones does not exceed a factor of two, which is comparable with the deviations in the calculation of biological shielding due to a variety in the protection properties of the materials used or in their thickness.
Display omitted
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The description of detectors based on measuring the secondary-emission current and results of their tests are presented. Multichannel profilometers with a range of
n
× 10
3
to 10
9
ions/(cm
2
s) ...have been created. This range is largely overlapped with the range from a few units to 10
6
ions/(cm
2
s), which is characteristic of scintillation and semiconductor detectors. Current profilometers are used in the region of the overlap to monitor their degradation under exposure to the beam. The current profilometers are used in the transit of low-intensity beams, and their sensitivity is higher than the sensitivity of Al
2
O
3
phosphors and Faraday cups by four orders of magnitude. A three-lamel probe has been created based on the secondary emission to measure the current of the internal accelerator beam with a lower-range value of 0.1 pA.
—
The scanning two-dimensional ionization profile monitor (IPM) has been upgraded for the beam diagnostics in beam transport lines. The main parts of the monitor are an extractor, a scanner, and two ...analyzers with a slit at which residual-gas ionization products collected from a beam path as long as 50 mm arrive. The current amplifier based on microchannel plates and a current collector are placed in sequence behind the slit in order to increase the IPM sensitivity under high-vacuum conditions (
n
× 10
−6
Pa). Two-dimensional beam profiles are obtained by scanning. A special electronic unit containing high-voltage supplies and collector-current meters has been created for the scanning and IPM control. Three upgraded IPMs have been placed between the accelerator and the physical facilities in each beamline of the DC-280 FLNR JINR cyclotron. Data processing and simultaneous display of experimental results from several IPMs are carried out by a program developed in the LabVIEW design environment. The minimum current of the
40
Ar ion beam with the energy of 5 MeV/nucleon at which the monitor is still operable is estimated to be several tens of picoamperes. The reliability of the upgraded IPM has been demonstrated by its operation.
—
The methodology and results of absolute dee voltage measurements using the X-ray spectrum method at the FLNR JINR cyclotrons are presented. An Amptek XR-100T-CdTe semiconductor detector was used to ...measure bremsstrahlung spectra. The technique was tested on the U-400M isochronous cyclotron and was used to adjust the high-frequency accelerating system to the operating mode during commissioning of the DC-280 cyclotron.
The cross sections for the reactions
165
Ho(γ, n)
164
Ho,
165
Ho(γ, 3n)
162m
Ho,
165
Ho(γ, 4n)
161
Ho,
165
Ho(γ, 5n)
160m1
Ho,
165
Ho(γ, 5n)
160
Ho, and
165
Ho(γ, 6n)
159
Ho were experimentally ...determined in the energy range from 50 to 110 MeV. Also, calculations were performed using the Geant4 code and the Talys program to determine the cross section of reactions in holmium samples. Calculation results are compared with the obtained experimental results. The dependence of the isomeric ratio
160m1
Ho/
160
Ho on the electron energy has been measured.
The design and the performance of the primary beam diagnostic system operating on a non-intercepting measurement method are described. It was assembled for operation under harsh environmental ...conditions. The main part of the beam detection system is the Ionization Beam Profile Monitor (IBPM) operating on the ionization of the residual gas principle. The primary beam diagnostic system provides data sufficient to plot spatial distributions of the beam current in the monitored area operating in on-line regime. It was used to monitor the profiles of 7 Li, 11 B, 32 S beams in the energy range of 30 ÷ 50 AMeV and 20 Ne, 40 Ar, 86 Kr, 132 Xe beams at 4 ÷ 5 AMeV. All measurements were performed under the conditions of high gamma and neutron flux. The diagnostic box was located in the vicinity of the accelerator, where the neutron flux was over 10 6 neutrons/cm 2 s. The beam current was in the range of a few nA up to 15 μA. The device operates in vacuum on the level of 10 -6 ÷10 -3 mbar without loss of resolution power at the beam current as low as a few nA. Long operation time and emergency situations do not lead to decrease of its operability.
Neutron yields during irradiation of structural metals and polymer film by argon, krypton, and xenon ions with 2.4 and 2.5 MeV/nucleon energies are measured on the CYTRACK and DC-110 cyclotrons. The ...angular distributions of neutrons from the target are measured. The LISE
++
is used for extrapolating the data obtained to other ions, their energy, and to other targets. The program was tested on experimental data found in the literature. As a result of comparison, it is established that the calculation results coincide with the experimental data within a coefficient of two.
The yields of neutrons produced in thick LiF, Be, C, Al, Al
2
O
3
, and Cu targets irradiated by Li, C, and N ions with energies below 1.75 MeV/nucleon are measured on the DC-60 cyclotron at the ...Institute of Nuclear Physics, Astana Branch, Kazakhstan. The experimental angular distributions of the neutron yields from the targets are measured and an empirical equation to describe the distributions is proposed. The measured neutron yields are compared with the figures calculated by the LISE++ program. The measured and predicted neutron yields in the reactions coincide to within a factor of 2.
A proportional counter designed for heavy ion flux measurements is described. The working gas of the counter is air. The counter is composed of three parallel glass-fiber frames with wire electrodes ...coiled on them. Based on the counter, there has been developed a diagnostic product measuring the density distribution of accelerated ion flux for radioelectronic device testing. To prevent the dependence of measurement results on weather conditions (atmospheric pressure, temperature, humidity) as well as on the type and energy of ions, there has been applied an automatic correction methodology. In the process of the set-up operation it has been established, that the counter is characterized by a high radiation resource, resistance to extreme downloads, adequate performance of up to 10
6
ions/s, it is not sensitive either to neutrons or to γ-quanta, and it is convenient to use.
The Genome-M facility for the automatic fast irradiation of thin biological samples with accelerated heavy ions at the U-400M cyclotron of the Flerov Laboratory of Nuclear Reactions, Joint Institute ...for Nuclear Research, is described. It allows a great deal of various samples to be irradiated within a few hours using radiation with preset and controlled characteristics. Methods for monitoring beam quality and calibrating the ionization chamber in absorbed dose units and the facility control software are also described.
