The Spin Physics Detector, a universal facility for studying the nucleon spin structure and other spin-related phenomena with polarized proton and deuteron beams, is proposed to be placed in one of the two interaction points of the NICA collider that is under construction at the Joint Institute for Nuclear Research (Dubna, Russia). At the heart of the project there is huge experience with polarized beams at JINR. The main objective of the proposed experiment is the comprehensive study of the unpolarized and polarized gluon content of the nucleon. Spin measurements at the Spin Physics Detector at the NICA collider have bright perspectives to make a unique contribution and challenge our understanding of the spin structure of the nucleon. In this document the Conceptual Design of the Spin Physics Detector is presented.

The Monte-Carlo calculations of the Moliere radius (RM) for some homogeneous and heterogeneous media used in electromagnetic calorimetry in the energy range from 50 MeV to 10 GeV are presented in detail. The obtained results, the uncertainties in determining RM, estimations of the absorbed energy, methods for approximating the absorbed energy, and the accuracy of the results are discussed as well. Some RM are shown for calorimeter proto-types of the Spin Physics Detector experiment (SPD). A one-parameter function of the Moliere radius dependence on the absorber-scintillator thickness ratio is obtained.

The study of the processes occurring in a matter when ionizing radiation passes through is important for solving various problems. Examples of such problems are applied and fundamental problems in the field of radiation physics, chemistry, biology, medicine and dosimetry. This work is dedicated to computer modeling of the parameters of a tungsten converter for studying the processes of radiation damage during the interaction of ionizing radiation with solutions of organic dyes. Simulation was carried out in order to determine the optimal thickness of the converter under predetermined experimental conditions. Experimental conditions include: energies and type of primary particles, radiation intensity, target dimensions, relative position of the radiation source and target. Experimental studies of the processes of radiation damage occurring in solutions of organic dyes are planned to be carried out using the linear electron accelerator "LINAC-300" of the National Scientific Center "Kharkov Institute of Physics and Technology". Electrons with 15 MeV energy are chosen as primary particles. The interaction of electrons with the irradiated target substances is planned to be studied in the first series of experiments. Investigations of the interaction of gamma quanta with the target matter will be carried out in the second series of experiments. The tungsten converter is used to generate a flux of bremsstrahlung gamma rays. One modeling problem is determination of the converter thickness at which the flux of bremsstrahlung gamma will be maximal in front of the target. At the same time, the flow of electrons and positrons in front of the target should be as low as possible. Another important task of the work is to identify the possibility of determining the relative amount of radiation damage in the target material by the Geant4-modeling method. Radiation damage of the target substance can occur due to the effect of bremsstrahlung, as well as electrons and positrons. Computational experiments were carried out for various values of the converter thickness – from 0 mm (no converter) to 8 mm with a step of 1 mm. A detailed analysis of the obtained data has been performed. As a result of the data analysis, the optimal value of the tungsten converter thickness was obtained. The bremsstrahlung flux in front of the target is maximum at a converter thickness of 2 mm. But at the same time, the flux of electrons and positrons crossing the boundaries of the target does not significantly affect the target. The computational experiment was carried out by the Monte Carlo method. A computer program in C++ that uses the Geant4 toolkit was developed to perform calculations. The developed program operates in a multithreaded mode. The multithreaded mode is necessary to reduce the computation time when using a large number of primary electrons. The G4EmStandardPhysics_option3 model of the PhysicsList was used in the calculations. The calculations necessary for solving the problem were carried out using the educational computing cluster of the Department of Physics and Technology of V.N. Karazin Kharkiv National University.

One of the main tasks of the electromagnetic calorimetry of the SPD setup is effective π0-γ separation in the energy range from 50 MeV to 10 GeV. Therefore, the current task is to optimize the design of the module cells in order to improve the physical parameters of the ECaL calorimeter. The Molière radius is determined in this work by the Monte Carlo method using Geant4 toolkit for various cell configurations of the calorimeter module. The results obtained in this work will be taken into account in the further development of the detecting systems of the ECaL SPD NICA.

The electromagnetic sampling calorimeters of the SPD experiment (NICA collider) are being investigated by Monte Carlo method. The simulation is used to study in detail the influence of energy leakages from the module on its energy resolution. The values of the stochastic and constant terms are obtained for the SPD calorimeter prototypes.

The response simulation of an ideal KOPIO-type electromagnetic sampling calorimeter was carried out in the energy range of 50 MeV - 16 GeV using Geant4-10.6.0 toolkit. In this work, we obtained energy resolution parameters for prototypes of Shashlyk calorimeter modules (ECAL SPD) of the NICA collider SPD setup for different thicknesses of a lead absorber with different numbers of layers. The NICA scientific experiment provides a unique opportunity to study parton distributions and correlations in hadron structure when working with high-intensity polarized relativistic ion beams. The ECAL electromagnetic calorimeter is one of the key detectors of the SPD device. There are some preliminary requirements for an electromagnetic calorimeter, in particular, for energy resolution in the energy range from 50 MeV to 16 GeV. It has been shown in detail that a more accurate obtaining of stochastic as well as permanent coefficients acting as parameters of the energy resolution parameterization formula is possible when longitudinal energy leakages from the calorimeter tower are taken into account. Such leakages are always present even in small amounts. Thus, the energy resolution parameterization of an ideal sampling calorimeter with a good chi(2)/ndf value is fitted with function of the type: sigma(E)/E = a/root E circle plus b circle plus (p(1) . ln(1) E + p(2) . ln(2) E + p(2) . ln(3) E), where the logarithm ln E means lnE/E-c, where E-c is the effective critical energy. Based on the results of detailed modeling, the dependence of these parameters on the number of calorimeter plates and absorber thicknesses was found. The approach is based on careful selection and analysis of the energy spectra obtained by modeling according to the chi-square criterion and an adequate choice of the approximation functions of the energy resolution. The methods proposed in this paper can be easily extended to other combinations of absorber-scintillator thicknesses.

The (Δ E 1 , Δ E 2 , E ) multidetector telescope has been developed and tested. The telescope is a compact combination of two 32-strip silicon Δ E 1 -, Δ E 2 -detectors and a scintillation E -detector, which is a 3 × 3 array of CsI(Tl) crystals. A timing signal can be obtained from any of the Si detectors for time-of-flight (TOF) measurements. Single-channel and 32-channel charge-sensitive preamplifiers have been developed and manufactured for the multidetector module to serve the Δ E - and E -detectors with high efficiency and sensitivity. Reaction products obtained in the 40 Ar (35 MeV/nucleon) + 9 Be reaction have been unambiguously identified in the experiment by mass number A and atomic number Z .

Обсуждается создание экспериментального комплекса на базе светосильного фрагмент-сепаратора КОМБАС и быстродействующего ионного кетчера. Представлены основные характеристики фрагмент-сепаратора КОМБАС и ионного кетчера, определяющие перспективность предлагаемой комбинации. Ожидается, что реализуемый комплекс позволит получать вторичные пучки радиоактивных ядер более высокого качества по сравнению с пучками, получаемыми методом “in-flight” сепарации. Планируется использование комплекса в тандеме с пост-ускорителем для получения моноизотопных и монохроматических интенсивных вторичных пучков радиоактивных ядер в широком диапазоне массовых чисел А и атомных номеров Z. Предлагается перечень перспективных научных задач, для реализации которых требуются высокие интенсивности и качество получаемых вторичных пучков экзотических ядер.

The development of an experimental facility based on the high-luminosity COMBAS fragment separator and a fast ion catcher is discussed. The main characteristics of the COMBAS fragment separator and the ion catcher determining the advantages of the proposed combination are presented. The developed facility is expected to allow production of secondary radioactive beams with a quality higher than the quality of beams obtained using the in-flight separation technique. It is planned that the facility will be used in a tandem with a post-accelerator for producing single-isotope and monochromatic high-intensity secondary radioactive beams in a wide range of mass numbers A and atomic numbers Z. A list of perspective scientific problems requiring high-intensity and high-quality secondary beams of exotic nuclei is proposed.

During the last 10 years a number of fundamental and applied research at the electrostatic charge-exchange accelerator EGP-10K INR NAS with the proton and deuteron beams were performed. Currently, the program of optimization of the accelerator parameters, especially – the energy and intensity of the beam has being implemented. At the same time the possibilities of the transport and use of the accelerator beam through the creation of additional sections of beam tube and reaction chambers, as well as the possibilities of the measurements and data processing particularly, in the reconstructed measuring center of the previous single-stage accelerator EG-5, were improved. This paper presents the results of modernization of infrastructure of the experimental studies with the beams of the accelerator EGP-10K using the latest equipment and modern digital technique for beam diagnostics, registration of the reaction products and visualization of the obtained data.

Приведены результаты анализа основных ионно-оптических характеристик фрагмент-сепаратора КОМБАС. В переднеугловых измерениях на фрагмент-сепараторе КОМБАС изучены импульсные распределения радиоактивных ядер 6, 8 и 9Li, полученных в реакции 11 (33 АМэВ, где А – массовое число частицы)) + 9 (332.6 мг/см2). С использованием пучков ядер 6, 8 и 9Li были измерены импульсный и угловой (по горизонтали) захваты сепаратора КОМБАС. Установлено, что размер изображения пучков ядер 6, 8 и 9Li в выходном ахроматическом фокусе сепаратора Fa приблизительно в два раза превышает размер пучка на производящей мишени (входной фокус F0), на которую первичный пучок диафрагмировался диаметром 6 мм. При интенсивности первичного пучка 11 5 мкА получены следующие интенсивности пучков: 6.9 · 105 частиц/с для 6, 2 · 104 частиц/с для 8 и 4.7 · 105 частиц/с для 9Li. Полученные значения достаточны для использования их в спектроскопических исследованиях. Предлагается использовать времяпролетный анализ продуктов ядерных реакций на выходе сепаратора КОМБАС не только для измерения энергии транспортируемых частиц во всем рабочем диапазоне импульсного захвата, но и для их идентификации по массе A и заряду Z без потери этих частиц. Проблему снижения загрузок детекторов и дальнейшего улучшения энергетического разрешения регистрируемых частиц предлагается решить установкой высокоразрешающего магнитного спектрометра после второй мишени, принимающей вторичные пучки радиоактивных ядер.

The experimental set-up based on the time-of-flight fragment-separator COMBAS and multi-channel registration system is developed for the studies of exotic light nuclei. Precise correlation method will be used for resonance decay spectroscopy.

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 F a approximately twofold exceed the size of the beam on a producing target (input focus F 0), 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.

Using fragment-separator COMBAS [1] in forward-angle measurements the velocity, isotopic and element distributions of products with Z<7 in B-11 (33AMeV) + Be-9 reaction have been studied. The yields of He-6,He-8 and Li-9 isotopes on the Be-9 thick target (332.6 mg/cm(2)) as a function of momentum acceptance of fragment -separator COMBAS have been measured. The production rates per 1p mu A of the primary beam of exotic nuclei of He-6 (6.9.10(5) pps), He-8 (2.10(4) pps) and Li-9 (4.3.10(5) pps) which can be used as secondary radioactive beams of halo -like nuclei have been determined. The two-neutron halo nuclei He-6,He-8 and Li-9 are of great current interest both as very neutron-rich nuclei with a significant neutron skin and in understanding the interactions of very neutron-rich nuclei. The Li-9 beam may be helpful in understanding of sub barrier fusion enhancement independent of the presence of the halo nucleons in used neutron - rich projectiles.

In present work it is proposed to implement the data acquisition system (DAQ COMBAS) for the fragment separator COMBAS(1) under freely distributed UNIX like operating system (OS) FreeBSD on base of the ngdp framework(2,3), which allows to build modular distributed DAQ. As a CAMAC subsystem the camac package(4) (DLNP JINR) is used, which encapsulates code deals with each supported crate controller into corresponding driver. Authors create the driver kh(4) for the PCl adapter of the CC02 controller(5) (Karazin Kharkov National University). The runtime configurable r2h(1) histogram server module is supposed. The histGUI(1) client module is intended for histograms viewing as well as for r2h(1) runtime control and configurating. The histGUI(1) client will not depend on DAQ and ngdp system libraries, so can be compiled under any OS equipped by the ROOT package(6).

A differential and integral relative electron excess spectra of an extensive air shower are calculated. Using the mathematical simulation, the magnetic induction from this electron excess and electromagnetic induction output pulses on the contacts of the magnetic sensor with defined parameters are calculated. It is shown that output pulses have a little sensitivity to the soft pari (<= MeV) of the energy excess electron spectra. This opens up possibilities for the development of an alternative method for the extensive air shower detection where the role of the amount fluctuation of low energy particles is very small. All the necessary results for the planning of a research experiment are obtained.

The data acquisition, transportation and processing (DAQ) systems for INR NASU and COMBAS setup (JINR, FLNR) are proposed on base of ngdp framework and camac package (JINR, DLNP). ROOT dedicated class representing events online allows to implement the runtime configurable histogram server. Ones clients with graphic interface are independent on another DAQ so suitable for any operating system supporting ROOT.

Using fragment‐separator COMBAS [1] in forward‐angle measurements the velocity, isotopic and element distributions of products with Z<7 in 11B(33 AMeV)+9Be reaction have been studied. The yields of 6,8He and 9Li isotopes on the 9Be thick target (332.6 mg/cm2) as a function of momentum acceptance of fragment ‐separator COMBAS have been measured. The production rates per 1pμA of the primary beam of exotic nuclei of 6He(6.9⋅105 pps), 8He(2⋅104 pps) and 9Li(4.3⋅10 5pps) which can be used as secondary radioactive beams of halo ‐like nuclei have been determined. The two‐neutron halo nuclei 6,8He and 9Li are of great current interest both as very neutron‐rich nuclei with a significant neutron skin and in understanding the interactions of very neutron‐rich nuclei. The 9Li beam may be helpful in understanding of sub barrier fusion enhancement independent of the presence of the halo nucleons in used neutron—rich projectiles.