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We have compared the luminescence decay from intact and pre-damaged Al2O3 crystals registered during single swift heavy ion and photo- picosecond laser pulse excitation (λex. = 440 nm). The decay curves measured during 1.2 ÷ 1.6 MeV/amu C, Ar, V, Kr, Xe ion irradiation at room temperature are composed of three components – fast (τ1 It was found that photoexcitation at 440 nm induces strong emission of F22+- centers with a lifetime of about 8 ns which is not detected during high energy ion irradiation. This is ascribed to the quenching effect of high density excitations in a particle track.

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 40Ar 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.

Lead converter was irradiated with electron beams with energies of 60, 80 and 100 MeV. And holmium samples were irradiated with a flux of bremsstrahlung, which was formed in a lead converter. The rates of about 20 photonuclear reactions in 165Ho, which are induced by bremsstrahlung, were measured. Simulations to determine the fluence of electrons, photons, neutrons for holmium samples and the reaction rates for the obtained isotopes in the samples were performed using the Geant4 code. For those radionuclides that are determined in experimental measurements, the results were compared.

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 × 103 to 109 ions/(cm2 s) have been created. This range is largely overlapped with the range from a few units to 106 ions/(cm2 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 Al2O3 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 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 activities of products of two photonuclear reactions (113In( γ , γ ’) 113m In and 115In( γ , γ ’) 115m In) and neutron capture (115In(n, γ ) 116m In) were measured. The measurements were made to verify that obtained activities (as well as some of their ratios) change sufficiently with the change of the energy, so that the activation of the indium could be recommended as a sensitive test for the control of the endpoint energy (and beam quality) of bremsstrahlung beams in an energy region usually used in radiation therapy. Mikrotron photon beam was used for photoactivation, and the source of neutrons was the mikrotron tungsten target itself, at energies higher than threshold for ( γ , n) reaction. At lower energies, neutrons were produced in Be target inserted in photon beam. It was obtained that sensitive index of endpoint energy variation can be obtained in a broad energy region from 5 MeV to 23 MeV by different combinations of saturation activities of three reaction products. The described measurements can be used to develop a very sensitive and simple method in a routine quality control of photon beams of megavoltage devices used in radiotherapy.

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.

The possibility for the production of exotic 6He nuclei in the 7Li(γ, p)6He reaction with the use of the 22 MeV electron beam provided by the MT-25 microtron was studied. This method was found to be quite effective tool for the production of the short-lived 6He ions. Two species of lithium salt, Li2CO3 and LiF, were tested as target material. Maximal yield of 6He atoms was obtained at irradiation of the fine-dispersed LiF salt loaded into cylindrical vessel. At the temperature of 800 °C the yield of 6He was found to be ( 1.7 ± 0.2 ) × 10 7 atoms / s per 1 μA of electron beam current. The use of the ECR source (with efficiency of about 8%) gave a possibility to obtain the beam of 6He ions with intensity of ( 1.4 ± 0.2 ) × 10 6 ions / s per 1 μA of electron beam current. The application of this approach for the further production of a monochromatic beam of accelerated 6He ions with an intensity higher than 108 pps (which can be easily reached already at 100 μA electron beam current) would make feasible a large number of experiments on investigating the structure of this nucleus and the mechanisms of nuclear reactions with its participation. This method for obtaining 6He nuclei may turn out to be one of the most optimal and inexpensive as compared with other methods using accelerated heavy ion projectiles.

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 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.

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.

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 106 ions/s, it is not sensitive either to neutrons or to γ-quanta, and it is convenient to use.

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 7Li, 11B, 32S beams in the energy range of 30 ÷ 50 AMeV and20Ne, 40Ar, 86Kr, 132Xe 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 106 neutrons/cm2 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.

The longitudinal velocity and isotopic distributions of forward emitted fragments have been measured in the 11 B (32.9 AMeV ) + 9 Be (27 Al ,197 Au ) reactions. The range of isotopes from Helium to Nitrogen has been observed. The particular interest of this experiment has been to investigate the influence of direct and dissipative processes on the fragment production for different targets. The fast velocity component characterized by a Gaussian shape is rather well described in the frame of simple statistical fragmentation model, but with smaller value of the width of the distribution. Isotopic and velocity distributions have been compared to Universal Parameterization model implemented in the LISE + + code. Increased yields of 4 He and 7 Li isotopes are observed as a possible influence of the cluster structure of the 11 B nuclei on the total reaction mechanisms.

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.

An monitor for control of accelerated particle flux density used in irradiation of polymer films with heavy ions with a low track density (103−5 × 107 cm−2) is based on detection of recoil protons. It has been designed to control irradiation of a film with a width of up to 650 mm and is composed of five PIN diodes with a hydrogenous target placed in front of each diode. The sensitivity of the monitor with a polyethylene target to the density of a xenon ion beam is described by a linear function; its value is (4.0±0.5) × 10−3 pulses/(ion/cm2). The instrument is capable of monitoring ion flux densities of

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 results from upgrade of an ionization beam profile monitor (IBPM) are presented. The IBPM consists of a conventional capacitor that extracts the ionization products of the residual gas and analyzing capacitors. The main objective of this upgrade was to create a device with uniform spatial resolution. For this purpose, an additional difference of potentials, the ramping of which allows the beam cross section to be scanned, is applied between the capacitors of the monitor, while the electric fields in the capacitors themselves remain constant. Two IBPMs have been developed as a result of the facility’s upgrade: an IBPM for on-line monitoring of the vertical and horizontal beam current distributions in the beam line in an area of 8 × 8 cm2 with a uniform 1-mm resolution, and an IBMP for detailed beam profile monitoring with a uniform resolution of 1 × 1 mm2 over the scanning region. It was established experimentally that the proposed scanning technique provides good results in beam profile measurements when the ion component of the ionized residual gas is extracted; for the electron component, the result is much worse.

The problem of magnetic field reconstruction inside a sub-region in R3 from magnetic measurements on the closed boundary of this sub-region is considered. Efficiency of the proposed method, the algorithm and associated software for precision magnet systems are discussed. The results of the software verification and numerical experiments are presented. A comparison between the reconstructed field and the measured field in the M1 magnet of the separator COMBAS is given. Requirements to the position accuracy of sensors consistent with the required accuracy of magnetic field reconstruction are defined. Recommendations on magnetic scheme design for field mapping are given. These investigations have been performed at the Flerov Laboratory of Nuclear Reactions, JINR.

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.

The operation principle of a newly designed ionization profilometer is described, and results of its tests with a 30-MeV/nucleon 40 Ar ion beam are presented. The measured beam density distribution over its cross section is given. The space resolution of this profilometer is ~1 〈 1 mm. The image of this beam on a fluorescent screen is shown for comparison. It is determined that the minimum value of the beam current at which it is still possible to measure its profile is 3 nA. The measurements were performed at residual gas pres- sures of 2 〈 10 -3 and 7 〈 10 -3 Pa.

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.

Thick coaxial Si(Li) detectors are fabricated to register long-range high-ionizing reaction products with high energy resolution. It is shown that charge collection efficiency and energy resolution strongly depend on cooling temperature and magnitude of voltage applied. The test experiments have shown that coaxial detectors are able to register the intermediate energy heavy ions with 0.5–0.7% resolution. The energy losses in entrance window of the detector are

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 physical principle of the neutron autoradiography (NARG) method consists in the registration of the distribution number of neutrons, which are scattered isotropically on the nuclei of a tested element, where as in conventional autoradiography the isotropic radiation of the nuclei investigated is recorded. The experimental investigation of the main features of NARG for hydrogen was done by using a resonance filter and a resonance detector made of metallic indium. To demonstrate the possibilities of the proposed method it was compared with the traditional methods of autoradiography and neutron radiography. The method NARG for thin objects gives an object contrast about 20 times higher than in the case of neutron radiography. The minimum detectable content of hydrogen in an object is achieved 6 · 10−5 g cm−2. The proposed method has a very high selectivity of hydrogen determination in any object. The high contrast and selectivity of the method enable one to investigate geological problems.

A method for the determination of absolute radon concentration by means of electrostatic collection of radon daughters at the surface of a track etch detector, followed by counting of single and paired (arising from genealogically correlated α-decays of the same nuclei) tracks is described.

When using antimony-beryllium neutron sources for activation analysis of the composition of a substance, the problem of the analytical monitoring of many elements can be solved with a limit of determination of 10−3–10−5%. Based on the data obtained by the authors concerning the spatial distribution of the neutrons from a124Sb−Be-source in different moderators, a beryllium-graphite assembly with a powerful124Sb source has been designed, manufactured, and introduced into operation, for neutron-activation analysis.

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.