The Spin Physics Detector collaboration proposes to install a universal detector in the second interaction point of the NICA collider under construction (JINR, Dubna) to study the spin structure of the proton and deuteron and other spin-related phenomena using a unique possibility to operate with polarized proton and deuteron beams at a collision energy up to 27 GeV and a luminosity up to 10^32 cm^-2 s^-1. As the main goal, the experiment aims to provide access to the gluon TMD PDFs in the proton and deuteron, as well as the gluon transversity distribution and tensor PDFs in the deuteron, via the measurement of specific single and double spin asymmetries using different complementary probes such as charmonia, open charm, and prompt photon production processes. Other polarized and unpolarized physics is possible, especially at the first stage of NICA operation with reduced luminosity and collision energy of the proton and ion beams. This document is dedicated exclusively to technical issues of the SPD setup construction.

The Spin Physics Detector is an experiment at NICA designed to study the spin structure of the proton and deuteron and the other spin-related phenomena using polarized beams. The collision energy is up to 27 GeV and the luminosity is up to 10 ^32 cm ^-2 s ^-1 in pp mode. Two scintillator-based detectors, Beam–Beam Counters (BBC), will be installed upstream and downstream the interaction point and will serve as a tool for beam diagnostics including local polarimetry. In this paper, we present the design of the BBC prototype based on the tiles with green WLS and SensL SiPM readout. FERS-5200 is used as the front-end readout system. The amplitude and timing resolutions for different tiles using radioactive source and cosmic rays are obtained.

The Spin Physics Detector is an experiment at NICA designed to study the spin structure of the proton and deuteron and other spin-related phenomena using polarized beams. Two Beam-Beam Counters (BBCs) will be installed symmetrically aside from the interaction point in the end-cups of SPD setup and will serve as a tool for beam diagnostics including local polarimetry. The outer part of the BBC wheel is based on fast scintillator tiles and cover the polar angels between 60 and 500 mrad. Different material configurations for the BBC prototype based on scintillator tiles were tested. The light collection depends on material combinations—fiber (Saint Gobain BCF91AS, BCF92S, and Kuraray Y-11), tile surface cover (Matted and double covered with Tyvek sheets tiles), and optical cement (CKTN mark E, OK-72). SensL 1 × 1 mm2 and 3 × 3 mm2 SiPMs were used as photosensors in the prototype tiles. The studies were performed with a cosmic rays test setup equipped with CAEN FERS-5200 readout system.

The Spin Physics Detector is an experiment at NICA designed to study the spin structure of the proton and deuteron and the other spin-related phenomena using polarized beams. Two endcap detector wheels of scintillator-based Beam-Beam Counters (BBCs) will be installed symmetrically aside from the interaction point and will serve as a tool for beam diagnostics including local polarimetry. The selection of material combinations for BBC is presented using scintillation tiles with different material combinations of the BBC prototype. The influence of the light collection was studied using matted and covered with Tyvek tiles. Different fibers (Saint-Gobain Crystals BCF91AS, BCF92S, and Kuraray Y-11), as well as different optical cements (CKTN type E, OK-72) were used. The prototypes were tested with cosmic rays and radioactive source using SensL SiPM readout.

Studies in many areas of particle and astroparticle physics require a good knowledge of hadron spectra produced at small angles to the primary particle direction, e.g. in the TeV energy range at the LHC. The present work is dedicated to development of a particle identification technique based on the transition radiation produced by highly relativistic particles. Dedicated experimental studies were carried out and simulation models were developed to reproduce experimental data obtained with different prototypes. On the basis of these studies, the possibility of making detectors able to provide hadron composition measurement with high accuracy and identify particles with high efficiency in the forward experiments at the LHC was demonstrated. Two concepts of large scale TRDs are proposed: the straw TRD and the GaAs/straw TRD. They allow the reconstruction of hadron spectra with accuracy about or below 1% and to identify particles with high efficiency in individual events. As an example, suppression of the combinatorial background was demonstrated for the D0→K−π+ and D̄0→ K+π− decays.

The Search for Hidden Particles (SHiP) Collaboration has proposed a general-purpose experimental facility operating in beam-dump mode at the CERN SPS accelerator to search for light, feebly interacting particles. The SHiP experiment incorporates two complementary detectors. The upstream detector is designed for recoil signatures of light dark matter (LDM) scattering and for neutrino physics, in particular with tau neutrinos. It consists of a spectrometer magnet housing a layered detector system with high-density LDM/neutrino target plates, emulsion-film technology and electronic high-precision tracking. The downstream detector system aims at measuring visible decays of feebly interacting particles to both fully reconstructed final states and to partially reconstructed final states with neutrinos, in a nearly background-free environment. The detector consists of a 50\m long decay volume under vacuum followed by a spectrometer and particle identification system with a rectangular acceptance of 5\,m in width and 10\,m in height. Using the high-intensity beam of 400\gev protons, the experiment aims at profiting from the $4\times 10^{19}$ protons per year that are currently unexploited at the SPS, over a period of 5--10 years. This allows probing dark photons, dark scalars and pseudo-scalars, and heavy neutral leptons with GeV-scale masses at sensitivities that largely exceed those of existing and projected experiments. The sensitivity to light dark matter reaches well below the dark matter relic density limits in the range from a few \mevcc up to 100\,MeV-scale masses, and it will be possible to study tau neutrino interactions with unprecedented statistics. This paper describes the SHiP experiment baseline setup and the detector systems, together with performance results from prototypes in test beams, as it was prepared for the 2020 Update of the European Strategy for Particle Physics.

In July 2018 an optimization run for the proposed charm cross section measurement for SHiP was performed at the CERN SPS. A heavy, moving target instrumented with nuclear emulsion films followed by a silicon pixel tracker was installed in front of the Goliath magnet at the H4 proton beamline. Behind the magnet, scintillating-fibre, drift-tube and RPC detectors were placed. The purpose of this run was to validate the measurement's feasibility, to develop the required analysis tools and fine-tune the detector layout. In this paper, we present the track reconstruction in the pixel tracker and the track matching with the moving emulsion detector. The pixel detector performed as expected and it is shown that, after proper alignment, a vertex matching rate of 87 % is achieved.

Dark matter is a well-established theoretical addition to the Standard Model supported by many observations in modern astrophysics and cosmology. In this context, the existence of weakly interacting massive particles represents an appealing solution to the observed thermal relic in the Universe. Indeed, a large experimental campaign is ongoing for the detection of such particles in the sub-GeV mass range. Adopting the benchmark scenario for light dark matter particles produced in the decay of a dark photon, with αD = 0.1 and mA′ = 3mχ, we study the potential of the SHiP experiment to detect such elusive particles through its Scattering and Neutrino detector (SND). In its 5-years run, corresponding to 2 · 1020 protons on target from the CERN SPS, we find that SHiP will improve the current limits in the mass range for the dark matter from about 1MeV to 300MeV. In particular, we show that SHiP will probe the thermal target for Majorana candidates in most of this mass window and even reach the Pseudo-Dirac thermal relic.

Dark photons are hypothetical massive vector particles that could mix with ordinary photons. The simplest theoretical model is fully characterised by only two parameters: the mass of the dark photon m _γ ^D and its mixing parameter with the photon, ε . The sensitivity of the SHiP detector is reviewed for dark photons in the mass range between 0.002 and 10 GeV. Different production mechanisms are simulated, with the dark photons decaying to pairs of visible fermions, including both leptons and quarks. Exclusion contours are presented and compared with those of past experiments. The SHiP detector is expected to have a unique sensitivity for m _γ ^D ranging between 0.8 and 3.3 ^+0.2_-0.5 GeV, and ε ^2 ranging between 10^-11 and 10^-17 .

A bstract Dark matter is a well-established theoretical addition to the Standard Model supported by many observations in modern astrophysics and cosmology. In this context, the existence of weakly interacting massive particles represents an appealing solution to the observed thermal relic in the Universe. Indeed, a large experimental campaign is ongoing for the detection of such particles in the sub-GeV mass range. Adopting the benchmark scenario for light dark matter particles produced in the decay of a dark photon, with α D = 0 . 1 and m A ′ = 3 m χ , we study the potential of the SHiP experiment to detect such elusive particles through its Scattering and Neutrino detector (SND). In its 5-years run, corresponding to 2 · 10 20 protons on target from the CERN SPS, we find that SHiP will improve the current limits in the mass range for the dark matter from about 1 MeV to 300 MeV. In particular, we show that SHiP will probe the thermal target for Majorana candidates in most of this mass window and even reach the Pseudo-Dirac thermal relic.

We propose to build and operate a detector that, for the first time, will measure the process $pp\to\nu X$ at the LHC and search for feebly interacting particles (FIPs) in an unexplored domain. The TI18 tunnel has been identified as a suitable site to perform these measurements due to very low machine-induced background. The detector will be off-axis with respect to the ATLAS interaction point (IP1) and, given the pseudo-rapidity range accessible, the corresponding neutrinos will mostly come from charm decays: the proposed experiment will thus make the first test of the heavy flavour production in a pseudo-rapidity range that is not accessible by the current LHC detectors. In order to efficiently reconstruct neutrino interactions and identify their flavour, the detector will combine in the target region nuclear emulsion technology with scintillating fibre tracking layers and it will adopt a muon identification system based on scintillating bars that will also play the role of a hadronic calorimeter. The time of flight measurement will be achieved thanks to a dedicated timing detector. The detector will be a small-scale prototype of the scattering and neutrino detector (SND) of the SHiP experiment: the operation of this detector will provide an important test of the neutrino reconstruction in a high occupancy environment.

Harsh radiation conditions, including the ones expected for the operation with High-Luminosity LHC, require detailed and careful quality control of any gas detector from the very beginning stage of assembly. The existing probe methods for cathode boards QC are able to find shorts to ground, shorts between pads, and breaks in the readout line at the initial stage of manufacturing. The cosmic test requires fully assembled detectors and reveals pads with absent or low amplitude analog signals associated with resistance in the readout trace line. In the current work, we propose the direct method of such a defect recognition for both bare cathode boards and fully assembled detectors and demonstrate the examples of a successful cure.

The gas detectors, operated under harsh radiation conditions like the one foreseen at the High Luminosity LHC (HL-LHC), must fulfill a number of stringent quality control criteria. Based on high-voltage current measurements, the X-ray scanning technique has been developed for discovery of various production defects prior to the readout electronics installation. The later usually happens at the last stage of detector assembly. Thus, it allows testing the quality of the chambers, identifying defects and when possible fixing them already at early stage.

Growing energies of particles at modern or planned particle accelerator experiments as well as cosmic ray experiments require particle identification at gamma-factors (γ) of up to ∼ 105. At present there are no detectors capable of identifying charged particles with reliable efficiency in this range of γ. New developments in high granular pixel detectors allow one to perform simultaneous measurements of the energies and the emission angles of generated transition radiation (TR) X-rays and use the maximum available information to identify particles. First results of studies of TR energy-angular distributions using gallium arsenide (GaAs) sensors bonded to Timepix3 chips are presented. The results are compared with those obtained using a silicon (Si) sensor of the same thickness of 500 μm. The analysis techniques used for these experiments are discussed.

The present version of the Transition Radiation (TR) simulation module implemented in the Geant4 toolkit describes very well experimental data for the TR energy distribution; however, it does not allow reproducing the details of angular distribution at small angles. In order to solve this problem, corrections to the existing x-ray TR module in Geant4 are proposed. With these corrections, the results of the simulations are in a good agreement with the angular TR distributions predicted by theory and obtained in the test beam measurements using a 480 um Si pixel detector and Mylar radiator.

Abstract The SHiP experiment is proposed to search for very weakly interacting particles beyond the Standard Model which are produced in a 400 GeV/c proton beam dump at the CERN SPS. About $$10^{11}$$ 1011 muons per spill will be produced in the dump. To design the experiment such that the muon-induced background is minimized, a precise knowledge of the muon spectrum is required. To validate the muon flux generated by our Pythia and GEANT4 based Monte Carlo simulation (FairShip), we have measured the muon flux emanating from a SHiP-like target at the SPS. This target, consisting of 13 interaction lengths of slabs of molybdenum and tungsten, followed by a 2.4 m iron hadron absorber was placed in the H4 400 GeV/c proton beam line. To identify muons and to measure the momentum spectrum, a spectrometer instrumented with drift tubes and a muon tagger were used. During a 3-week period a dataset for analysis corresponding to $$(3.27\pm 0.07)~\times ~10^{11}$$ (3.27±0.07)×1011 protons on target was recorded. This amounts to approximatively 1% of a SHiP spill.

The Search for Hidden Particles (SHiP) experiment proposal at CERN demands a dedicated dipole magnet for its scattering and neutrino detector. This requires a very large volume to be uniformly magnetized at B > 1.2 T, with constraints regarding the inner instrumented volume as well as the external region, where no massive structures are allowed and only an extremely low stray field is admitted. In this paper we report the main technical challenges and the relevant design options providing a comprehensive design for the magnet of the SHiP Scattering and Neutrino Detector.

The SHiP experiment will search for very weakly interacting particles beyond the Standard Model which are produced in a 400 \GeV/$c$ proton beam dump at the CERN SPS. About $10^{11}$ muons per spill will be produced in the dump. To design the experiment such that the muon-induced background is minimized, a precise knowledge of the muon spectrum is required. To validate the muon flux generated by our Pythia and GEANT4 based Monte Carlo simulation (FairShip), we have measured the muon flux emanating from a SHiP-like target at the SPS. This target, consisting of 13 interaction lengths of slabs of molybdenum and tungsten, followed by a 2.4 m iron hadron absorber was placed in the H4 400~\GeV/$c$ proton beam line. To identify muons and to measure the momentum spectrum, a spectrometer instrumented with drift tubes and a muon tagger were used. During a three-week period a dataset for analysis corresponding to $(3.27\pm0.07)~\times~10^{11}$ protons on target was recorded. This amounts to approximatively 1\% of a SHiP spill.

New developments of pixel detectors based on GaAs sensors offer effective registration of the transition radiation (TR) X-rays and perform simultaneous measurements of their energies and emission angles. This unique feature opens new possibilities for particle identification on the basis of maximum available information about generated TR photons. Results of studies of TR energy-angular distributions using a 500 |j.m thick GaAs sensor attached to a Timepix3 chip are presented. Measurements, analysis techniques and a comparison with Monte Carlo (MC) simulations are described and discussed.