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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-section function for the $$^{115}$$ In( $$\gamma $$ , $$\gamma ^{\prime }$$ ) $$^{115m}$$ In reaction was determined in the energy range up to E $$_\gamma $$ = 9.6 MeV using the bremsstrahlung facility at the MT25 Microtron, JINR, Dubna. Natural indium disks were irradiated with bremsstrahlung, each disk with a beam of different endpoint energy. To the measured saturation activity built up in the wide-energy photon beam we applied the unfolding technique, developed recently at the JRC-Geel with the primary purpose of being used in neutron activation. The results were compared with TALYS 1.9 calculations and existing experimental data. Our results suggest that the application of existing unfolding technique allow determining unknown excitation functions of photon-induced reactions.

Accurate determination of the energy of LINAC-200 fast electrons was performed using several photonuclear reactions carried out on natural Indium after conversion of electron energy in bremsstrahlung in thick Tungsten target. Natural Indium was used as an activation detector and the ratios of saturation activities R( 113m In)/R( 115m In), R( 114m In)/R( 115m In) and R(111In)/R ( 115m In) were used as a measure of the endpoint energy of the bremsstrahlung beam (and energy of electrons striking the bremsstrahlung target as well). Energy dependence of the three ratios of saturation activities were determined by using the bremsstrahlung produced by electrons accelerated by Microtron to the energies known with accuracy not worse than 0.1 MeV. Three types of scintillation detectors (LaBr3:Ce, BGO and plastic) were calibrated using electrons having energies from 1.17 MeV to 25 MeV. In low energy region photoelectrons produced by 60 Co gamma radiation in the detector itself were used, as well as high energy electrons (from 11 MeV to 25 MeV) accelerated by LINAC-200.

The yields of neutrons produced in thick LiF, Be, C, Al, Al2O3, 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.

Neutron emission was observed experimentally at the DC-60 cyclotron at the Institute of Nuclear Physics (Astana, Kazakhstan). The neutron yields were measured in the bombardment of light-element (Be, C, Al, Al2O3, and LiF) targets with heavy ions (Ar, Kr, and Xe) with energies below the Coulomb barrier. The angular distributions of neutrons from the targets were also measured. It was found that the observed neutrons were produced in secondary nuclear reactions between the resting target nuclei and recoil nuclei that acquire energy in the process of elastic scattering. The experimental results were compared with calculations based on the abovementioned secondary-reaction mechanism. The calculations allow one to estimate the yields of secondary reactions to within a coefficient of 2.

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 time-of-flight system for low intensity heavy ion beam energy measurements based on scintillation detectors is presented. Parameters of the experimental setup and the data processing algorithm are described. The accuracy of the method is no worse than ±1.5%.

The basic ion-optical characteristics of the COMBAS fragment separator are analyzed. The momentum distributions of radioactive 6He, 8He, and 9Li nuclei obtained in the reaction 11B (33 A MeV, where A is the mass number of a particle) + 9Be (332.6 mg/cm2) have been investigated in forward-angle measurements on the COMBAS fragment separator. The momentum and angular (horizontal) acceptances of the COMBAS separator have been measured using the 6He, 8He, and 9Li beams. It has been ascertained that the images of the 6He, 8He, and 9Li nuclear beams in final achromatic focus of the separator Fa approximately twofold exceed the size of the beam on a producing target (input focus F0), at which the primary beam has a diameter of 6 mm. The intensities of 6He, 8He, and 9Li beams obtained at a 5-μA intensity of the primary 11B beam are 6.9 × 105, 2 × 104, and 4.7 × 105 particles/s, respectively. These values are sufficient for use in spectroscopic measurements. It is proposed that time-of-flight analysis of nuclear reaction products at the exit from the COMBAS separator will be used not only to measure the energy of transported particles over the whole operating range of the momentum acceptance, but also to identify them by mass A and charge Z without loss of these particles. The problem of reducing the count rates of detectors and further improvement of their energy resolution for detected particles can be solved by placing a high-resolution magnetic spectrometer past the second target accepting the secondary radioactive nuclear beams.

The possibility of producing exotic 6He nuclei in the 7Li(γ, p) reaction with 22 MeV electron beam at the MT-25 microtron in the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research (FLNR JINR), is studied. The 6He yield from the Li2CO3 target made up 6 × 105 s−1 per 1 μA of the electron beam current. The obtained result is quite promising, taking into account the further improvement of the target unit, the possibility of using another lithium compound, and the increase in the target material temperature and the electron beam current up to 20 μA. The application of this approach for the further production of a monochromatic beam of accelerated 6He nuclei with an intensity on the order of 107 s−1 would make a large number of experiments on investigating the structure of this nucleus and the mechanisms of nuclear reactions with its participation feasible. This method for obtaining 6He nuclei may turn out to be one of the most optimal (and inexpensive) currently available.

Kinematics of two-body Coulomb breakup of a prototype 11B nucleus into 4He and 7Li fragments is considered. The factors affecting the accuracy in measuring the breakup parameters are analyzed, and the corrections having an influence on the accuracy in reconstructing the primary parameters of the cluster breakup are estimated. A method for estimating the effect of an unknown contamination in the target and the use of this method for separating true and background events are discussed. The influence of background factors occurring in heavy ion fragmentation reactions is analyzed, and random coincidences due to high background fluxes of parasitic products are estimated. It is proposed to use magnetic analysis of correlated breakup products to reduce the background particle flux and substantially (by several orders of magnitude) improve the accuracy in measuring the cluster energies.

The detailed overview of the Roscosmos new high energy (20-60 AMeV) ion beam line based on U400M cyclotron and the features of diagnostic set-up used for ion beam parameters evaluation and control during SEE tests are presented.

The high-resolution wide aperture separator COMBAS was installed and commissioned in the Flerov Laboratory of Nuclear Reactions, JINR (Dubna) [Nucl. Instr. and Meth. A 306 (1991) 123; 426 (1999) 605; 479 (2002) 467]. It is designed for in-flight radioactive beam production of short-lived isotopes and experiments with them. The separator operates in the (20–50)A MeV ion energy region. It consists of the two stages, dispersive and achromatising. The second half of the separator is a mirror symmetrical counterpart of the first one, the intermediate focal plane being the plane of the symmetry. Multipole magnets with special profiled poles are used to correct higher order aberrations at the intermediate and final foci. The 3D magnetic measurements of the analysing magnets of the separator were done. The KOMPOT program for the 3D magnetic field calculations [Doinikov et al., 1986, Preprint/CNNI atominform: B-0741, 13p; Belyaev et al., Int. Conf. “Optimisation of Finite Element Approximations”, St.Pt., Russia, 25–29 June 1995, p.101; IEEE Transact. On Magnetics, 28 (1) (1992) 908; Frenkel, Selected works, USSR Academy of Sciences publ., Moscow–Leningrad, v.1 (Electrodynamics), 1956; Proc. IEEE, 114 (7) (1967) 995; Livingston, Blewett, Particle accelerators, No. 7, McGraw-Hill, 1962, p. 253] was used for the analysis of these magnetic measurements data, as well as for the reconstruction of the magnet fields inside the total volume closed by the 3D surface, where the magnetic measurements had been performed. As a result of the magnetic field reconstruction we obtained field maps, which would be used in simulations of particle trajectories.

A systematic study of the forward-angle production of nuclei with 2⩽Z⩽11 induced in nucleus–nucleus collisions of 18O with 9Be and 181Ta in the Fermi energy domain (35 A MeV) has been performed. The reaction products were measured by using the double achromatic fragment-separator COMBAS in the spectrometry mode. The inclusive velocity, the isotopic and element distributions were measured. The dominant role of low-energy reaction mechanisms is observed.

The high-resolving wide aperture separator COMBAS has been designed and commissioned at the FLNR, JINR. Three-component magnetic measurements of all the magnets were performed. The measured data allow reconstruction of the 3D-distributions of the fields in all the magnets. 3D-maps are needed for particle trajectory simulations throughout the entire separator. The magnetic fields of analysing magnets, M 1 , M 2 , M 7 , and M 8 , contain quadrupole components of alternating sign that provide necessary beam focusing. All the magnets M 1 –M 8 , contain sextupole and octupole field components, which minimizes the second and third order aberrations. All this allowed one to increase their apertures, to form effectively a beam of the required sizes and to decrease the channel length.

A systematic investigation of the forward-angle inclusive yields of 2≤Z≤11 isotopes produced in collisions of 18O projectile nuclei with a 9Be target in the Fermi energy region (35A MeV) is performed. The measurements were based on the use of the COMBAS double achromatic kinematical separator in the spectrometry mode at the Flerov Laboratory of Nuclear Reactions at the Joint Institute for Nuclear Research, FLNR (JINR, Dubna). The velocity, isotopic, and element distributions are presented. There is no unique mechanism that would explain the total set of results obtained in this experiment. A dominant role of low-energy reaction mechanisms is observed. The intensity of secondary beams of halolike nuclei 11Li, 12Be, and 14Be is determined.

Experiments are performed to determine the isotopic composition of the induced activity of a tungsten target for a 10 MeV electron beam. The measurement results are used to calculate the dose rate from the induced activity of the target for an accelerator with 100 kW beam power. It is established that 187W radiation makes a substantial contribution to the dose rate. The neutron yield from the target and the flux density of neutrons scattered in the accelerator room are estimated.

The COMBAS large solid angle and high momentum acceptance and high-resolving kinematic separator has been created at the Flerov Laboratory of Nuclear Reactions, JINR, to efficiently collect extremely short-lived nuclei near the zero angle which are produced in intermediate energy fragmentation reactions with wide momentum and wide angular distributions. For the first time the M 1 M 2 M 3 M 4 F d M 5 M 6 M 7 M 8 F a magneto-optical configuration of the COMBAS separator has been realized on the strong focussing principle. The separation and trajectory analysis of particles by the separator are carried out by three parameters: the magnetic rigidity (B· ρ ), the energy loss difference in the degrader (Δ E /Δ x ) and the time-of-flight (Δ T ) of the analyzed particles. The COMBAS separator can be used efficiently both in the mode of a high- resolving spectrometer to study reaction mechanisms and in the mode of an in-flight separator in experiments on the synthesis and study of properties of short-lived exotic nuclei near the drip-lines.

Using fragment‐separator COMBAS [1] in forward‐angle measurements the velocity, isotopic and element distributions of products with Z

Performance and characteristics of a large volume electronic track detector, time projection chamber (TPC), are described. The spatial resolution in the Z (vertical) direction is 0.2 mm, in the Y (horizontal) direction is 1 mm and the double track resolution in the Y- and Z-direction is 4.5 mm and 10 mm, respectively. A possible utilization of the TPC for experiments with heavy ions is discussed.

The authors present and analyze the results of full-scale measurements of the neutron and bremsstrahlung fields around the MT-22 microtron. Dose rates for neutron radiation and bremsstrahlung were measured both for the radiation emerging from the moderating target assembly impinged directly on the concrete shielding and for radiation emerging from the target assembly surrounded on three sides with lead shielding. The second case was found to provide the worst radiation protection; the moderating target was unprotected at the top while the lead itself served as a thick neutron converter. Bremsstrahlung was determined with a scintillation detector while neutron dose distributions were measured with a corona counter. Some activation reactions and their resulting radionuclides, generated in the irradiation of target and shielding materials, are given.