The characteristics of a 50-cm-long module of the scintillation time-of-flight hodoscope have been studied. It has been determined that the coordinate resolution and detection efficiency of the module depend on the voltages applied to the voltage dividers of the photomultiplier tubes and the distance from the hip point of a particle to the photomultiplier tubes. The module has been tested using both a secondary electron beam of the Pakhra accelerator (Lebedev Physical Institute, Russian Academy of Sciences) with an energy of 20 MeV and a 90Sr+90Y radioactive source. The tests show that the minimum values of the coordinate resolution are σx ≈ 0.1 and 1.3 cm, respectively, and the detection efficiency is ε ≈ 53

The scintillation amplitude−coordinate spectrometer with a thickness of 0.58X0 has been calibrated using cosmic radiation. The light signals in the spectrometer are detected by FEU-49 and FEU-85 photomultiplier tubes, which determine the amplitude and coordinate systems, respectively. It has been established that the relative amplitude and coordinate resolutions depend on the point of particle incidence on the spectrometer. The relative amplitude and coordinate resolutions measured at the center of the spectrometer appear to be the best, and their values are 8.7

The paper describes the design of a prototype magnetic field compensator intended to eliminate the influence of the edge magnetic field of the S-25P Pakhra accelerator magnet, Lebedev Physical Institute, on the electron beam during its output. The results of the study showed that this design could reduce an external magnetic field of B0 0.1 T to zero values inside the prototype.

— The characteristics of the calibration beam of secondary electrons at the Pakhra accelerator based on the SP-3 magnet at the Lebedev Physical Institute are presented. The energy resolution of a beam with a 2-mm-thick copper converter in the electron energy range E = 5–100 MeV is δ ≈ 10%.

The results of studies of the characteristics of the prototype of the scintillation time-of-flight hodoscope 71 cm long are presented. Prototype testing using a 90Sr + 90Y radioactive source showed that the coordinate resolution and detection efficiency depend on the source position on the work surface. The best coordinate resolution and the highest detection efficiency were found at the module center as σx ≈ 1.2 cm and ε ≈ 9

The results of measurements of the light yield and light collection inhomogeneity of prototypes of scintillator detectors with transverse dimensions of 75 × 75 mm 2 and 150 × 150 mm 2 , which are elements of the ScWall in the BM@N experimental setup that is designed to measure the charges of light fragments in heavy ion collisions, are presented. The measurements were carried out on the electron beam of the “Pakhra” synchrotron of the Lebedev Physics Institute of the RAS.

A new Time-of-Flight (ToF) detector of the NA61/SHINE hadron spectrometer at CERN SPS based on Multigap Resistive Plate Chambers (MRPCs) technology is offered as a substitution of the scintillation ToF detector developed in 1990s. In 2019-2020, a prototype module of the new ToF system was tested on the 280 MeV/c positron beam to determine its characteristics. The analogue front-end electronics and DRS4-based waveform digitizer were used as a readout chain. This article presents the results of the MRPC test with analogue readout obtained in 2019-2020.

— A two-channel scintillation spectrometer with a thickness of 0.5 X 0 was calibrated using cosmic muons and a beam of secondary quasi-monochromatic electrons with energies of 3−100 MeV at the Pakhra accelerator оf the Lebedev Physical Institute. The scintillation signals were detected in the spectrometer by FEU-52 photomultiplier tubes. The dependences of the relative energy resolution of the individual spectrometer channels on the electron energy were found to be identical. The relative energy resolutions of the spectrometer channels and the sum of the signals from both channels were ~11 and ~7%, respectively, at an electron energy E ≈ 32 MeV.

A multichannel scintillation spectrometer with a thickness of 2.5X0 has been calibrated on a secondary electron beam with energies of 23−280 MeV at the Pakhra accelerator of the Lebedev Physical Institute. The relative energy resolution of the spectrometer is determined by the electron energy and the spectrometer thickness. The best relative energy resolution of the spectrometer is attained at an electron energy of ~90 MeV; its values are δ = 13 and 9.4% at spectrometer thicknesses of 1.0X0 and 2.5X0, respectively.

Designs of hodoscopes of nuclear fragments based on quartz and scintillation plates with light pickup by silicon avalanche photodiodes are described. Hodoscopes are planned for use in the BM@N experiment for registration of heavy nuclear fragments near the axis of the heavy ion beam. The results of measurements of light yields in detector elements based on quartz and scintillation plates on the electron beam of the synchrotron "Pakhra" (LPI) are presented. The measured nonuniformity of the light collection shows that readout from both sides of hodoscope detector elements is needed.

In this paper, we report the characteristics of the generated beams, the extracted electron beam and the beam of secondary electrons/positrons, of the LPI accelerator complex Pakhra as of November 2019 for testing and calibrating detectors used in large accelerator and astrophysical experiments. At energies of 250–500 MeV of the electron beam ejected into Hall 1 from the S-25R synchrotron, its energy resolution is δ ~ 1% and the intensity can be changed by collimators in the range of 10 3 –10 10 s –1 . The quasi-monochromatic beam of secondary electrons produced in Hall 2 typically has an energy in the range of 50–300 MeV, a corresponding energy resolution of δ = 14–2%, and an intensity of ~ 10 2 s –1 . The performed simulation of the characteristics of the secondary positron beam allowed selecting the optimal geometry of the setup and showed good agreement with the experimental data obtained later.

The calibration results are presented for a scintillation hodoscopic spectrometer of charged particles, which has been designed for an experiment on the search for a heavy electron on the bremsstrahlung photon beam at the Pakhra accelerator of the LPI. The relative energy and coordinate resolutions of the spectrometer at electron energy E = 40 MeV are δ = 22% and σx = 9.5 mm, respectively. It has been determined that the width of electromagnetic showers in the transverse direction can be described by the energy dependences Δ ~ lnE at E < 100 MeV and Δ ~ 1/expE at E > 100 MeV.

Two versions of a forward hodoscope have been developed and manufactured based on scintillation and radiation-resistant quartz plates. The hodoscopes are designed to register ions in the BM @ N experiment at the NICA accelerator complex. The light outputs and their inhomogeneity were measured as a function of the coordinates of the passage of particles through the hodoscope plates on the calibration beam of the secondary electrons of the "Pakhra" synchrotron of the Lebedev Physical Institute.

The possibility of using the effect of full energy release in a light scintillator when an electron beam passes through it to determine the energy characteristics of a low- and medium-energy beam (the “absorbed energy” method) is experimentally shown. Using scintillation detectors with thicknesses of 14.5, 20, 23.5, and 51.2 cm, the energy calibration of the quasi-monochromatic electron beam of the Pakhra FIAN accelerator was performed. For electron-beam energies of up to ~100 MeV and scintillation-detector thicknesses from 5 to 20 cm, the accuracy of determining the electron-beam energy may be 10–20%, respectively.