T10 Beam Research Articles

A prototype for the SHiP timing detector

The proposed SHiP experiment located at the CERN SPS will search for feebly interacting particles with masses below 10 GeV/c2. A veto timing detector will reject combinatorial di-muon backgrounds by requiring event to be coincident in time within 100 ps. The baseline option for the timing detector consist of scintillating bars read out by arrays of silicon photomultipliers. The detector comprises 546 bars of EJ200 scintillating material with dimensions 168 cm × 6 cm × 1 cm broken into three columns and covering an active area of 5 m × 10 m. The end of each bar is read out by an array of eight silicon photomultipliers attached to custom PCBs and subsequently read out by a DAQ system based on a SAMPIC chip. We present test beam results on a single column 22 bar prototype for the SHiP timing detector. Measurements were taken at the T10 beam line of the CERN PS. A timing resolution across the detector is found to be about 90 ps. The particle identification capability using a time of flight method is also demonstrated.

Off-Axis Characterisation of the CERN T10 Beam for low Momentum Proton Measurements with a High Pressure Gas Time Projection Chamber

We present studies of proton fluxes in the T10 beamline at CERN. A prototype high pressure gas time projection chamber (TPC) was exposed to the beam of protons and other particles, using the 0.8 GeV/c momentum setting in T10, in order to make cross section measurements of low energy protons in argon. To explore the energy region comparable to hadrons produced by GeV-scale neutrino interactions at oscillation experiments, i.e., near 0.1 GeV of kinetic energy, methods of moderating the T10 beam were employed: the dual technique of moderating the beam with acrylic blocks and measuring scattered protons off the beam axis was used to decrease the kinetic energy of incident protons, as well as change the proton/minimum ionising particle (MIP) composition of the incident flux. Measurements of the beam properties were made using time of flight systems upstream and downstream of the TPC. The kinetic energy of protons reaching the TPC was successfully changed from ∼0.3 GeV without moderator blocks to less than 0.1 GeV with four moderator blocks (40 cm path length). The flux of both protons and MIPs off the beam axis was increased. The ratio of protons to MIPs vary as a function of the off-axis angle allowing for possible optimisation of the detector to select the type of required particles. Simulation informed by the time of flight measurements show that with four moderator blocks placed in the beamline, (5.6 ± 0.1) protons with energies below 0.1 GeV per spill traversed the active TPC region. Measurements of the beam composition and energy are presented.

The New CERN Low-energy Facilities for Neutrino Detector Tests

The beamlines at CERN’s North and East Areas offer secondary beams in a wide range of momenta between 0.5 GeV/c and 400 GeV/c for fixed-target experiments as well as for test beam campaigns with a flexible configuration and variable beam composition and intensities. Recently, two new facilities for neutrino detectors tests have been established in an extension of the CERN North Area in context of the CERN Neutrino Platform project. These new tertiary beams extend the current capabilities of the H2 and H4 beamlines towards lower momenta in the range of 0.3 GeV/c to 12 GeV/c, respectively 7 GeV/c, and currently serve the two ProtoDUNE prototype detectors. In addition, a complete overhaul of the CERN East Area is underway, which will provide secondary beams with momenta of up to 15 GeV/c (T9 beam) and 12 GeV/c (T10 beam). New beam optics and an optimised design will allow for electron, hadron and muon beams with high purity. We discuss the layout and performance of both North and East Area beamlines as well as the available infrastructure for the neutrino detector community.

A beam–beam monitoring detector for the MPD experiment at NICA

The Multi-Purpose Detector (MPD) is to be installed at the Nuclotron Ion Collider fAcility (NICA) of the Joint Institute for Nuclear Research (JINR). Its main goal is to study the phase diagram of the strongly interacting matter produced in heavy-ion collisions. These studies, while providing insight into the physics of heavy-ion collisions, are relevant for improving our understanding of the evolution of the early Universe and the formation of neutron stars. In order to extend the MPD trigger capabilities, we propose to include a high granularity beam–beam monitoring detector (BE–BE) to provide a level-0 trigger signal with an expected time resolution of 30 ps. This new detector will improve the determination of the reaction plane by the MPD experiment, a key measurement for flow studies that provides physics insight into the early stages of the reaction.In this work, we use simulated Au+Au collisions at NICA energies to show the potential of such a detector to determine the event plane resolution, providing further redundancy to the detectors originally considered for this purpose namely, the Fast Forward Detector (FFD) and the Hadron Calorimeter (HCAL). We also show our results for the time resolution studies of two prototype cells carried out at the T10 beam line at the CERN PS complex.

The Projectile Spectator Detector for measuring the geometry of heavy ion collisions at the CBM experiment on FAIR

The Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) is aimed to explore the QCD phase diagram in the region of high baryon densities . The Projectile Spectator Detector (PSD) is the forward hadron calorimeter that will be used in the CBM to measure the event centrality as well as the reaction plane orientation in heavy-ion collisions in the beam energy range of 2–11 A GeV with beam interaction rates up to 10 MHz. The supermodule consisting of 9 modules has been assembled to explore the performance of the PSD. Its response has been studied with proton beams in the momentum range 2–10 GeV/c at the CERN Proton Synchrotron (PS) T9 and T10 beam lines. For the first time, the energy resolution and the linearity of the response have been measured at such low energies. The PSD operation under radiation conditions at the CBM, as well as the results of one PSD module measurements with irradiated photodetectors are discussed. • The PSD hadron calorimeter properties have been measured at test beams. • A simulation of the PSD operation under radiation conditions is conducted. • Degradation of photodetectors as a result of neutron irradiation is discussed.

Time resolution measurements with SiPMs coupled to a scintillator

This paper reports on the results of time resolution measurements of detectors consisting of SiPMs coupled to a scintillator. The R&D has been performed both in a cosmic-ray setup, at the Bologna INFN laboratories, and in a beam test, at the CERN T10 beam line. Different couplings, direct or by means of optical fibres, have been tested. The measurements indicate that to reach better time resolutions, it is important to have a direct coupling between the SiPM and the scintillator. A time resolution of 67 ps has been achieved, for the direct coupling, broadened by the full electronics chain jitter.

The PSD CBM Supermodule Response Study for Hadrons in Momentum Range 2 – 6 GeV/c at CERN Test Beams

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Study of the counting rate capability of MRPC detectors built with soda lime glass

We report the results of three MRPC detectors built with soda lime glass and tested in the T10 beam line at CERN. The detectors consist of a stack of 280μm thick glass sheets with 6 gaps of 220μm. We built two identical MRPCs, except one had the edges of glass treated with resistive paint. A third detector was built with one HV electrode painted as strips. The detectors' efficiency and time resolution were studied at different particle flux in a pulsed beam environment. The results do not show any improvement with the painted edge technique at higher particle flux. We heated the MRPCs up to 40°C to evaluate the influence of temperature in the rate capability. Results from this warming has indicated an improvement on the rate capability. The dark count rates show a significant dependence with the temperature.

Beam test of FARICH prototype with digital photon counter

In June 2012 we tested a Focusing Aerogel RICH detector prototype based on Digital Photon Counters (DPC) by Philips at the CERN PS T10 beam line with a particle momentum up to 6GeV/c. The prototype comprises a 20×20cm2 photon detector with 48×48 DPC pixels. In order to reduce the dark count rate, the photon detector was cooled to −40°C in addition to disabling individual DPC's microcells. A four layer focusing aerogel radiator with 200mm focal distance was studied. We obtained a Cherenkov angle resolution of 3.61±0.04mrad. The mean number of photoelectrons in a ring is 12. Directly measured π/K separation at 6GeV/c momentum is 3.5σ, μ/π separation is 5.3σ at 1GeV/c. A comparison with a Monte Carlo simulation is presented as well.

Micro-gap parallel-plate chambers with porous secondary electron emitters

We developed a micro-gap (0.1mm) parallel-plate chamber with one or more layers of solid converters of radiation. The detector with a one-layer converter was tested with X-rays (6–30keV) and also at the T9 and T10 beam facilities at CERN. A position resolution better than 30μm was achieved. With minimum ionizing particles, efficiency close to ∼20% was achieved with one detector, and it was almost twice as high as the efficiency due to the interaction of minimum ionizing particles with the gas alone. The detectors with a few layers of converter were tested only with X-rays. An efficiency of ∼10% could be achieved. The combination of a micro-gap PPC with secondary-electron converters may allow a further improvement of the time resolution of these detectors, which has already reached 50–100ps at present.

Four-layer aerogel Cherenkov counter

A 4-layer design of aerogel threshold counters using two refractive indices was suggested for the particle identification in the forward region of the BaBar detector. Three prototypes filled with the high quality aerogel produced in Novosibirsk were tested at T10 beam at CERN. Monte Carlo code was developed for the simulation of the light collection in aerogel counters. Monte Carlo results based on measured PTFE reflection coefficient and aerogel absorption and scattering lengths are in agreement with experiment.