Data taking has been started at the first stage of the SPASCHARM experiment on systematic study of the spin effects in strong interactions. The current setup configuration is described, and the detector characteristics attained during the beam data taking in the runs of 2018–2022 are listed.

The 10 m(2 )muon hodoscope made of drift tubes with length of 3.7 m and diameter of 52 mm is under development and construction at the NRC Kurchatov Institute-IHEP. In total, 768 drift tubes are grouped into six identical multilayers, each consisting of two tube layers with parallelly placed tubes. The orientation of tubes in adjacent multilayers is orthogonal; thus, the hodoscope has six X and six Y layers of tubes. The mechanical structure, on-chamber electronics, and data acquisition system are described. Expected technical characteristics and some test results are presented.

The SPASCHARM experiment is aimed at a systematic study of the nucleon spin structure and the spin dependence of the strong interaction of antimatter and matter with matter at energies up to 45 GeV. As part of the first stage of the experiment, the study of the spin properties of hadrons will take place in a beam of negatively charged hadrons on existing beamline 14 at the operating SPASCHARM setup at the U70 facility. At the second stage, the production of polarized beams of protons and antiprotons is envisaged in beamline 24A of the U-70 accelerator facility. A polarized antiproton beam will certainly become a unique beam in the world. It is planned to measure single-spin asymmetries in dozens of reactions, both on hydrogen and on various nuclei. At the SPASCHARM facility, it is also possible to measure the transverse polarization of hyperons and elements of the spin density matrix of vector mesons. The spin structure of the nucleon will be investigated in the study of quarkonium production to determine the contribution of gluons to the proton spin. The presence of two types of polarized beams and eight types of nonpolarized beams (π ± , K ± , p , p̅ , d , C ), in combination with a polarized target, expands the range of studies of polarization phenomena and enhances the uniqueness of the project.

(SVD-2 Collaboration) A. G. Afonin, E. N. Ardashev, V. F. Golovkin, S. N. Golovnya, S. A. Gorokhov, A. A. Kiryakov, A. G. Kholodenko, V. V. Konstantinov, L. L. Kurchaninov, I. S. Lobanov, E. V. Lobanova, G. A. Mitrofanov, V. S. Petrov, A. V. Pleskach, M. K. Polkovnikov, V. N. Riadovikov*, V. N. Ronzhin, V. A. Senko,N. A. Shalanda, M. M. Soldatov, Yu. P. Tsyupa, A. P. Vorobiev, V. I. Yakimchuk, and V. N. Zapolskii∗ IHEP, Protvino, Moscow region, Russia.

The control system for the detectors of the SPASCHARM experimental setup that is being developed at the U-70 accelerator complex (Protvino) is described. The general design concept of the control system and an example of application of the EPICS software are considered. The electronic modules of the control system that have been put in operation as of the present are described.

The data-acquisition system of a muon tomograph based on the on-chamber electronics is described. Its advantages over the previously used system based on the electronics made to the VME-9U standard are considered. The hardware component and the software of the new data-acquisition system are presented.

The LE-73 and LE-78 modules of MISS system designed for readout and recording of signals from multiwire chambers and hodoscopes are described. The use of an Altera FPGA provides a means for producing different modifications of the modules and adapting their operation to specific requirements of experimental setups. Owing to the availability of a high-speed internal memory, it is possible to design time-to-digital converters with a “common stop” and a 5-ns step and to store data in an internal FIFO memory.

The results of an analysis of data from the SERP-Е-184 experiment devoted to studying mechanisms of the production of charmed particles in proton–nucleus interactions at 70 GeV and their decays are presented. The data in question were obtained upon irradiating the SVD-2 active target consisting of carbon, silicon, and lead plates with a beam of 70-GeV protons. A detailed simulation on the basis of the FRITIOF7.02 and GEANT3.21 code packages made it possible to optimize event-selection criteria and to calculate the detection efficiency for Λ c + baryons. After selecting a signal from the threebody decay of a Λ c + baryon, the inclusive cross section for its production at near-threshold energies, its lifetime, and the parameter of the A dependence of the cross section were found. The Λ c + -baryon yields are tabulated along with data from other experiments and theoretical predictions.

The on-chamber electronic system of a muon tomograph is described. The system is composed of an MT-48 48-channel front-end module and an RMT-48 fan-out module for the multiplication of control signals. The data-acquisition structure for the Muon Tomograph device is presented.

A data acquisition system of the OKA experiment on studying rare kaon decays on the U-70 accelerator is described. The basis of the blocked data acquisition system was the high-speed multichannel information system MISS with autonomous controllers that read out the front-end electronics in the sequential data reading mode and buffering data during the accelerator burst. Data stored in the buffer memory are read out and processed at the end of the accelerator burst. The DATE package builds subevents from event fragments and events from subevents via the event building network. The event building network with the star topology is made with 1GbE-interfaces and 24 × 1 Gb E-switch. The GlusterFS cluster file system underlies the distributed storage system.

A new experiment SPASCHARM for systematic study of polarization phenomena in inclusive and exclusive hadronic reactions is currently under commissioning at IHEP. The universal experimental setup will detect dozens of various resonances and stable particles produced in collisions of unpolarized beams with the polarized target, and at the next stage, using polarized beams. At the first stage with polarized target, the final states composed of light quarks (u, d, s) will be reconstructed. Hyperon polarization and spin density matrix elements of the vector mesons will be measured along with the single-spin asymmetries. The 2π-acceptance in azimuth, which is extremely useful for reduction of systematic errors in measurements of spin observables, will be implemented in the experiment. The solid angle acceptance of the setup, Δθ≈250 mrad vertically and 350 mrad horizontally in the beam fragmentation region, covers a wide range of kinematic variables pT and xF. This provides the opportunity for separating dependences on these two variables which is usually not possible in the setups with a small solid angle acceptance. Unlike some previous polarization experiments, the SPASCHARM will be able to simultaneously accumulate and record data on the both, charged and neutral particle production.

Описана система накамерной электроники мюонного томографа: 48-канальный регистрирующий модуль МТ-48 и разветвитель сигналов канала управления РМТ-48. Приведена организация сбора информации установки “Мюонный томограф”.

The EuroMISS electronic system, designed for creation of data acquisition systems of Institute of High-Energy Physics (IHEP) physical setups, is described. This system results from the evolution of the MISS system and is implemented in the mechanical Euromechanics standard. The data transmission channel is based on a 16-bit VME bus. The main supply voltage is +5 V, and the additional voltages are +3.3 and −5.2 V. The slow-control subsystem available in the EuroMISS, firstly allows one to configure universal and specialized programmable microcircuits and, secondly, monitor serviceability of system modules by reading values of certain parameters. The list of EuroMISS modules and their brief description are given.

The stages of development and the current status of the versatile “Spectrometer with a Vertex Detector” setup designed for physics experiments at the U-70 accelerator of the Institute for High Energy Physics (Protvino) is described. The main detectors of the setup are the vertex detector based on silicon microstrip detectors, the wide-aperture magnetic spectrometer based on multiwire proportional chambers, and the lead-glass hodoscope γ detector. In the setup, there is a fast two-level trigger system for selecting required particle interactions. The key characteristics of the setup systems are presented, and the physical results obtained on it are briefly listed.