Search

The LHCb detector has been upgraded to manage a five-fold increase in the instantaneous luminosity delivered to the experiment during LHC Run 3 and to readout data at the full bunch crossing rate of 40 MHz. The enhanced LHCb RICH detectors now feature Multianode Photomultiplier Tubes (MaPMTs), covering a total area of approximately 4 square meters, and brand-new frontend electronics to comply with the trigger-less readout architecture. The opto-electronics chain is capable of detecting single photons at repetition rates of up to 100 MHz/cm 2 while maintaining an exceptionally low noise. The RICH upgrade is comprehensively outlined, including details about the characterization and studies on the photon detection system. The stability and uniformity achieved by optimizing the parameters of the opto-electronics chain enable the RICH system to function successfully and to provide excellent charged hadron identification in high occupancy conditions. [ABSTRACT FROM AUTHOR]

RI-RICH, a ring-imaging Cherenkov counter for radioactive ions, has been developed to measure the velocity of the ions at intermediate energies. Our RI-RICH system consists of six multi-anode photomultiplier tubes covered with 360-nm bandpass filters and a radiator made of quartz or BK7. For the primary 132Xe beam with a velocity of β = 0. 712 , a velocity resolution of Δ β ∕ β = 4. 9 × 1 0 − 4 (one standard deviation σ) and a detection efficiency of more than 99.99% were achieved. For the secondary beams with Z = 44 – 55 and β ≃ 0. 70 , we successfully performed particle identification using the B ρ - Δ E - β method. The velocity resolutions of RI-RICH for these nuclides were equivalent to a more than 6 σ separation for the mass number. [ABSTRACT FROM AUTHOR]

The ALICE collaboration is proposing a new apparatus, ALICE 3, to investigate the Quark Gluon Plasma (QGP) properties. In this context, conceptual studies for the development of a RICH detector for ALICE 3 are ongoing. The proposed baseline layout is a proximity-focusing RICH, using aerogel (refractive index n = 1.03 at λ ph = 400 nm) as Cherenkov radiator and a layer of Silicon Photomultipliers (SiPM) for the photon detection. A multi-layer (focusing) aerogel layout, with increasing refractive index, is also considered. If good time resolution of ≈ 20 ps can be achieved in the SiPM photons detectors, they can be able to identify charged hadrons via TOF measurements. The detector specifications and performance, obtained by means of dedicated Monte Carlo simulation, are presented. The R&D challenges related to the proposed design are also discussed. [ABSTRACT FROM AUTHOR]

The hadron particle identification provided by the RICH system in LHCb over a momentum range of 2.6–100 GeV/c has been a key element of the success of the experiment and will remain equally important for Upgrade II. With luminosities expected up to 7.5 times those expected for Upgrade I and 75 times those realised in the past, maintaining the current excellent particle identification performance demands a substantial improvement in the precision of the measurements of the space and time coordinates of the photons detected in the RICH. It will require a readout strategy with high-resolution timing information and making significant improvements in the resolution of the reconstructed Cherenkov angle. [ABSTRACT FROM AUTHOR]

The ALICE High Momentum Particle IDentification (HMPID) is a Ring Imaging Cherenkov detector that identifies π, k and p in the transverse momentum interval 1 < p T < 5 GeV/ c. The HMPID consists of seven proximity focusing RICH modules, 1.3 × 1.3 m2 each. They are based on liquid C 6 F 14 as Cherenkov radiator, and on MWPCs equipped with CsI pad segmented photocathodes as photon detector. During the LHC Long Shutdown 2 (LS2, 2019–2021) the HMPID underwent upgrading activities that increased the event read out rate up to ∼20 kHz, 10 times faster than in Run 2. The performance of the read-out electronics and the MWPCs status after a stop of 4 years, using the first Run 3 data (2022), are presented. The HMPID will also constraint the measurement of the inelastic (anti-)deuteron inelastic cross section in the momentum interval 0.2–2 GeV/ c. For such aim during LS2 two aluminium absorbers 1.3 × 1.3 m2, one with a thickness of 8 cm, half interaction length, and the other with a thickness of 4 cm, were installed in front of two RICH modules. Preliminary Monte Carlo results on the expected uncertainties on the cross section measurement are given. Finally, the projection of the CsI photocathodes stability at the end of Run 3 after the absorption of a charge dose ten times higher than in Run 2, is discussed. [ABSTRACT FROM AUTHOR]

COMPASS RICH-1 has used high-purity perfluorobutane as radiator gas since 2001. The operation and control of the radiator gas has evolved over years with continuous improvements. We report on the experience gained in the 20 year-long operation of perfluorobutane as COMPASS RICH radiator. Very accurate values for the radiator gas refractive index are needed for high-performance particle identification. The procedure has evolved over years and the one presently in use, which provides refractive index estimate at the 1 ppm level, is discussed. Perfluorobutane procurement is becoming challenging, and the minimization of material waste is now a priority for the protection of the environment. Commercially available perfluorobutane needs dedicated filtering before usage and typical material losses in the filtering procedure were around 30%. Recent efforts allowed us to reduce them to about 5%. A potential alternative to fluorocarbon radiators in gaseous RICHes is also presented. [ABSTRACT FROM AUTHOR]

As a part of the LHCb RICH Future upgrades experimental program, we studied hydrophobic aerogel tiles from Chiba University during the 2021 CERN SPS testbeam. In a 180 GeV/c proton beam, we tested aerogels with different refractive indices and different thicknesses. The Cherenkov light radiated from aerogel tiles was focused by a lens and registered by an array of MAPMTs. The number of detected photons per Cherenkov ring for a 2 cm thick aerogel tile with refractive index of 1.03 was around eight and in good agreement with the Monte Carlo simulation. We estimate the photon production yield to be about 50 photons/cm. [ABSTRACT FROM AUTHOR]

The COMPASS RICH-1 detector has undergone a major upgrade in 2016 with the installation of four novel MPGD-based photon detectors. They consist of large-size hybrid MPGDs with multi-layer architecture composed of two layers of Thick-GEMs and bulk resistive MicroMegas. A dedicated high voltage power supply system, based on CAEN HV modules, has been built and put in operation: it controls more than 100 HV channels. The system is required to protect the detectors against errors by the operator, monitor voltages and currents at a 1 Hz rate and automatically react to detector misbehavior. It includes also a HV compensation system against environmental pressure and temperature variation to grant the detector stability. The operation of a MPGD based single photon detector poses challenging requirements to the high voltage power supply systems employed in terms of high-resolution diagnostic features and dynamic voltage control. Systems satisfying all the needed features are not commercially available; for this reason a novel single channel high voltage system matching the MPGD needs has been designed and realized. In this article the COMPASS RICH-1 MPGD HV system implementation is described as well as its performance in terms of stability of the novel MPGD-based photon detectors during the physics data taking at COMPASS. The design, implementation and performance of a novel HV power supply system based on DC to DC converters and controlled by a FPGA device is presented. The capabilities of the first prototype of the new single HV channel power supply are illustrated when operated with a MPGD based single photon detector during a test beam exercise. The preliminary result of the multi channel system are briefly discussed. [ABSTRACT FROM AUTHOR]

Abstract The evolution and the present status of the gaseous photon detectors technologies are reviewed. The most recent developments in several branches of the field are described, in particular the installation and commissioning of the first large area MPGD-based detectors of single photons on COMPASS RICH-1. Investigation of novel detector architectures, different materials and various applications are reported, and the quest for visible light gaseous photon detectors is discussed. The progress on the use of gaseous photon detector related techniques in the field of cryogenic applications and gaseous or liquid scintillation imaging are presented. [ABSTRACT FROM AUTHOR]

Abstract COMPASS is a fixed target experiment at CERN SPS aimed to study Hadron Structure and Spectroscopy. Hadron Identification in the momentum range between 3 and 55 GeV/c is provided by a large gaseous Ring Imaging Cherenkov Counter (RICH-1). To cope with the challenges imposed by the new physics program of COMPASS, RICH-1 has been upgraded by replacing four MWPCs based photon detectors with newly developed MPGD based photon detectors. The architecture of the novel detectors is a hybrid combination of two layers of THGEMs and a MicroMegas. The top of the first THGEM is coated with CsI acting as a reflective photo-cathode. The anode is segmented in pads capacitively coupled to the APV-25 based readout. The new hybrid detectors have been commissioned during 2016 COMPASS data taking and stably operated during 2017 run. In this paper all aspects of the novel photon detectors for COMPASS RICH-1 are discussed. Highlights • For the first time, single photons are detected by MPGDbased photon detectors in the upgrade of COMPASS RICH1. • The novel photon detectors are hybrid ones including two THGEM layers and a MicroMegas multiplication stage. The first THGEM also acts as photoconverting layer (CsI). • In 2017 the novel MPGDbased photon detectors have operated stably at gains above 1 0 4 for the first time in an experimental environment. • m 2 The detector deadtime due to current sparks is kept minimum; spark rate 10/day/ m 2 with recovery time 10 s. [ABSTRACT FROM AUTHOR]

During the Long Shutdown 2 of the LHC, the LHCb RICH system has undergone an upgrade to implement the LHCb trigger strategy which increased the read-out rate from 1 MHz to 40 MHz. The new challenging operating conditions of the upgraded experiment required the replacement of the Hybrid Photon Detectors with Multi-Anode Photomultiplier tubes (MaPMT) and the introduction of new customised front-end electronics. The new RICH detectors have a modular design to facilitate maintenance and assembly. The fundamental core element is the Elementary Cell (EC), which is composed of one or four MaPMTs, depending on the type of the MaPMT, and the associated front-end electronics. An overview of the protocols and testing facilities which have been designed and put in place to perform the quality assurance programme is presented. This process lasted more than six years and included the testing and characterisation of the new front-end electronics, the MaPMTs, the ECs, and the photon detector assembly (columns), commissioning, and installation of the columns in the LHCb cavern. [ABSTRACT FROM AUTHOR]

The paper discusses the importance of particle identification in particle physics experiments, and reviews the impact of ring imaging Cherenkov (RICH) counters in experiments that are currently running, or are under construction. Several analysis methods are discussed that are needed to calibrate a RICH counter, and to align its components with the rest of the detector. Finally, methods are reviewed on how to employ the collected data to efficiently separate one particle species from the other. [ABSTRACT FROM AUTHOR]

We have developed a RICH counter as a new forward particle identification device for the Belle II experiment. As a Cherenkov radiator in this counter, a dual aerogel layer combination consisting of two refractive indicies, n =1.045 and 1.055, is employed. Mass production of these aerogel tiles has been done during 2013–2014 with new method improved by Chiba group. Optical qualities for them have been examined. The refractive indices of the obtained tiles were found to be in good agreement with our expectations, and the transparencies were high enough to be used for the RICH radiator. [ABSTRACT FROM AUTHOR]

In 2015, the LHCb experiment established a new and unique software trigger strategy with the purpose of increasing the purity of the signal events by applying the same algorithms online and offline. To achieve this, real-time calibration and alignment of all LHCb sub-systems is needed to provide vertexing, tracking, and particle identification of the best possible quality. The calibration of the refractive index of the RICH radiators, the calibration of the Hybrid Photon Detector image, and the alignment of the RICH mirror system, are reported in this contribution. The stability of the RICH performance and the particle identification performance are also discussed. [ABSTRACT FROM AUTHOR]

This article describes Cherenkov light imaging techniques used in the particle and nuclear physics experiments, concentrating on the author’s personal overview of selected recent counters. [ABSTRACT FROM AUTHOR]

The RICH-1 Detector of the COMPASS experiment at CERN SPS has undergone an important upgrade for the 2016 physics run. Four new photon detectors, based on Micro Pattern Gaseous Detector technology and covering a total active area larger than 1.2 m 2 have replaced the previously used MWPC-based photon detectors. The upgrade answers the challenging efficiency and stability quest for the new phase of the COMPASS spectrometer physics programme. The new detector architecture consists in a hybrid MPGD combination of two Thick Gas Electron Multipliers and a MicroMegas stage. Signals, extracted from the anode pad by capacitive coupling, are read-out by analog F-E based on the APV25 chip. The main aspects of the COMPASS RICH-1 photon detectors upgrade are presented focussing on detector design, engineering aspects, mass production, the quality assessment and assembly challenges of the MPGD components. The status of the detector commissioning is also presented. [ABSTRACT FROM AUTHOR]

The CBM-RICH detector is designed to identify electrons with momenta up to 8 GeV/ c and high purity as this is essential for the CBM physics program. The detector consist of a CO 2 -gaseous radiator, a spherical mirror system, and Multi-Anode PhotoMultiplier Tubes (MAPMT) of type H12700 from Hamamatsu as photon detectors. The detector concept was verified through R&D studies and a laterally scaled prototype. The results were summarized in a TDR, in which open issues were defined concerning the readout electronics, the shielding of the magnetic stray field in the MAPMT region, the radiation hardness of the MAPMT sensors, and the mechanical holding structure of the mirror system. In this article an overview is given on the CBM RICH development with focus on those open issues. [ABSTRACT FROM AUTHOR]

A large area imaging Cherenkov detector is under construction to provide hadron identification in the momentum range between 3 and 8 GeV/c for the CLAS12 exeperiment at the new 12 GeV electron beam of the Jefferson Laboratory (JLab). The detector adopts a hybrid optics solution with aerogel radiator, light planar and spherical mirrors and highly-segmented photon detectors. Cherenkov photons will be imaged either directly (for forward tracks) or after two mirror reflections (large angle tracks). The status of the detector construction is here reported. [ABSTRACT FROM AUTHOR]

A large area ring-imaging Cherenkov detector will be operated for hadron identification in the 3 GeV / c to 8 GeV / c momentum range at the CLAS12 experiment at the upgraded continuous electron beam accelerator facility of Jefferson Lab. The detector, consisting of aerogel radiator, composite mirrors and photon counters, will be built with a hybrid optics design to allow the detection of Cherenkov light for both forward and large angle hadron tracks. The active area has to be densely packed and highly segmented, covering about 1 m 2 with pixels of 6 mm 2 , and to allow a time resolution of 1 ns. A technology that can offer a cost-effective solution and low material budget could be Silicon Photomultipliers (SiPM) thanks to their high gain at low bias voltage, fast timing, good single-photoelectron resolution and insensitivity to magnetic fields. An investigation is ongoing on samples of 3 × 3 mm 2 SiPM of different micro-cell size to assess the single photon detection capability in the presence of high dark count rate due to thermal generation effects, after-pulses or optical cross-talk and to study the response to the moderate radiation damage expected at CLAS12. In this work, a brief review of the latest and most interesting results from these studies will be shown. [ABSTRACT FROM AUTHOR]

The two RICH detectors in LHCb have been successfully collecting data since 2010. They are essential for most of the physics publications from LHCb. An upgrade of the LHCb detector is designed so that, from 2021 onwards, it can collect data corresponding to 5 fb −1 of integrated luminosity per year, in order to improve the statistical precision of the physics measurements and to search for very rare B-decays and D-decays. As part of the RICH upgrade, the HPDs will be replaced by MaPMTs in both RICH detectors. The prototypes of MaPMTs and their readout have been tested. The optics of the upstream RICH will be modified, which involves rebuilding most parts of this detector. An overview of the developments for the RICH upgrade and the corresponding particle identification performance are reported. [ABSTRACT FROM AUTHOR]

In this article 1 1 The paper was presented at the RICH 2016 conference, Bled, Slovenia, September 2016. we explore the angular resolution limits attainable in small FDIRC designs taking advantage of the new highly pixelated detectors that are now available. Since the basic FDIRC design concept attains its particle separation performance mostly in the angular domain as measured by two-dimensional pixels, this paper relies primarily on a pixel-based analysis, with additional chromatic corrections using the time domain, requiring single photon timing resolution at a level of 100–200 ps only. This approach differs from other modern DIRC design concepts such as TOP or TORCH detectors, 2 2 See presentation at this conference. whose separation performances rely more strongly on time-dependent analyses. We find excellent single photon resolution with a geometry where individual bars are coupled to a single plate, which is coupled in turn to a cylindrical lens focusing camera. [ABSTRACT FROM AUTHOR]

High precision flavor physics measurements are an essential complement to the direct searches for new physics at the LHC ATLAS and CMS experiments. Such measurements will be performed using the upgraded Belle II detector that will take data at the SuperKEKB accelerator. With 40x the luminosity of KEKB, the detector systems must operate efficiently at much higher rates than the original Belle detector. A central element of the upgrade is the barrel particle identification system. Belle II has built and installed an imaging-Time-of-Propagation (iTOP) detector. The iTOP uses quartz optics as Cherenkov radiators. The photons are transported down the quartz bars via total internal reflection with a spherical mirror at the forward end to reflect photons to the backward end where they are imaged onto an array of segmented Micro-Channel Plate Photo-Multiplier Tubes (MCP-PMTs). The system is read out using giga-samples per second waveform sampling Application-Specific Integrated Circuits (ASICs). The combined timing and spatial distribution of the photons for each event are used to determine particle species. This paper provides an overview of the iTOP system. [ABSTRACT FROM AUTHOR]

The evolution and the present status of the gaseous photon detectors technology are reviewed. Recent developments in several branches of the field are described, in particular the installation of the first large area MPGD-based detectors of single photons for the upgrade of COMPASS RICH-1. Promising advancement in cryogenic and other applications of gaseous photon detector related techniques are mentioned and the quest for visible light gaseous photon detectors is discussed. [ABSTRACT FROM AUTHOR]

The Time-of-Propagation (TOP) detector is a new type of ring-imaging Cherenkov detector developed for particle identification in the barrel region of the Belle II spectrometer. In the assembly and installation, it is crucial for the detector performance to achieve precision alignment and secure gluing of the optical components as well as to mechanically support them managing the stress, attitude, optical and electrical contacts, and limited installation space. Various efforts were made to develop the procedures and jigs along with the development of the mechanical structure. Such efforts accomplished the assembly and installation in April and May 2016, respectively, without a significant incident. [ABSTRACT FROM AUTHOR]

AMS-02 is a high-energy particle physics magnetic spectrometer installed on the International Space Station since May 2011, and operating continuously since then. The AMS-02 Ring Imaging Čerenkov counter (RICH) is a specialised sub-detector for the precise measurement of the particle velocity β with a resolution of Δ β / β = 0.7 ( 2.4 ) × 10 − 3 for helium nuclei passing through the Aerogel (NaF) radiator. From the emitted photon counting the particle absolute charge magnitude | Z | can be estimated with an uncertainty of 0.3 charge units for helium nuclei. In 5 years of operations the optical properties of the RICH had no significant degradation and the performances of the detector have been stable in time. By means of the simultaneous use of the Silicon Tracker and the RICH, AMS is able to investigate the isotopic composition of cosmic rays in the kinetic energy range from few GeV/n to ∼10 GeV/n for elements with charge | Z | up to 4 with unprecedented statistics. The precise measurement of cosmic rays light nuclei isotopes ratio, such as 3 He/ 4 He and 10 Be/ 9 Be, provide important constraints to the free parameters in the models for cosmic rays propagation in our Galaxy. In particular the mass distinction between 3 He and 4 He needed for the measurement of the 3 He/ 4 He flux ratio is obtained by statistical methods. The excellent simulation of the AMS detector provides the precise description needed for this analysis. Moreover, the use of the geomagnetic field for selecting control samples of CRs with enhanced abundances of heavy isotopes provides an independent tool for the study of the light nuclei isotopic composition with AMS. [ABSTRACT FROM AUTHOR]

The Compressed Baryonic Matter (CBM) experiment at the future Facility for Anti-proton and Ion Research (FAIR) will investigate the phase diagram of strongly interacting matter at high net-baryon density and moderate temperature in A+A collisions. One of the key detectors of CBM to explore this physics program is a Ring Imaging CHerenkov (RICH) detector for electron identification. For a high performance of the RICH detector precise mirror alignment is essential. A three-step correction cycle has been developed, which will be discussed: First a qualitative, fast check of the mirror positions, second a quantitative determination of possible misalignments and third a software correction routine, allowing a proper functioning of the RICH under misalignment conditions. [ABSTRACT FROM AUTHOR]

The ALICE apparatus is dedicated to study the properties of strongly interacting matter under extremely high temperature and energy density conditions. For this, enhanced particle identification (PID) capabilities are required. Among the PID ALICE detectors, the ALICE-HMPID (High Momentum Particle IDentification) detector is devoted to the identification of charged hadrons, exploiting the Cherenkov effect. It consists of seven identical RICH modules, with liquid C 6 F 14 as Cherenkov radiator ( n ≈1.298 at λ =175 nm). Photon and charged particle detection is performed by a MWPC, coupled with a pad segmented CsI coated photo-cathode. The total CsI active area is 10.3 m 2 . The HMPID provides 3 sigma separation for pions and kaons up to p T = 3 GeV / c and for kaons and (anti-)protons up to p T = 5 GeV / c . A review of the HMPID PID performance, in particular in the challenging central Pb–Pb collisions, and its contribution to the ALICE physics program, using the LHC RUN1 (2010–2013) and RUN2 (2015) data, are presented. [ABSTRACT FROM AUTHOR]

The fixed target experiment NA62 at CERN aims at measuring the ultra-rare decay K + → π + ν ν ¯ , whose branching ratio is of the order of 10 −11 . The main challenges faced by the experiment to achieve a 10% precision measurement are the required beam intensity and background rejection factor. The differential Cherenkov detector KTAG must be able to tag charged kaons in an unseparated hadron beam with an average particle rate of 750 MHz, of which 45 MHz are kaons, with a time precision of at least 100 ps and an efficiency higher than 95%. The additional pion contamination must be kept lower than 10 −4 . The RICH has been designed to separate charged pions from muons in the momentum range 15 < p < 35 GeV / c , contributing to a further muon rejection factor of 100. In order to match the upstream and downstream activity, a time resolution similar to the one of KTAG must be achieved. The RICH is also used as a primitive trigger generator for the level-0 trigger system. The construction and commissioning of both detectors was completed and their performances were studied during the 2014–2015 runs. [ABSTRACT FROM AUTHOR]

TRICK is a project funded by the INFN CSN5 Young grant 2020. It will use an innovative 5D technique to provide information about 3D position, time, and ID of the incoming particles. The proposed idea is based on the well-known technology of GEM-based TPC together with conventional Aerogel proximity focussing RICH in a single box. Both parts, TPC and RICH, will be read out simultaneously and instrumented with the same TIGER ASIC developed for the BESIII CGEM-IT detector. By combining information from both systems, the TRICK technique will improve the performance of each instrument: precise time information will help the extraction of the TPC position, while tracking will help the rings identification, by measuring the expected centre, also in a magnetic field. The TRICK-box prototype, instrumented with triple-GEM and Hamamatsu H12700 MA-PMT, aims to achieve a spatial resolution of 100 μ m, time resolution below 1 ns, and 3 σ separation for π / K up to 4 GeV. This paper introduces the project and focuses on the initial studies with the prototype, the preparation of the first cosmic stand, and the next steps. [ABSTRACT FROM AUTHOR]

We report about the development status of large area gaseous single photon detectors based on a novel hybrid concept for RICH applications. The hybrid concept combines Thick Gaseous Electron Multipliers (THGEMs) coupled to CsI, working as a photon sensitive pre-amplification stage, and Micromegas, as a multiplication stage. The most recent achievements within the research and development programme consist in the assembly and study of 300 × 300 mm 2 hybrid photon detectors, the optimization of front-end electronics, and engineering towards large area detectors. Hybrid detectors with an active area of 300 × 300 mm 2 have been successfully operated in laboratory conditions and at a CERN PS T10 test beam, achieving effective gains in the order of 10 5 and good time resolution ( σ = 7 ns ); APV25 front-end chips have been coupled to the detector resulting in noise levels lower than 1000 electrons; the production and characterization of 300 × 600 mm 2 THGEMs is ongoing. A set of hybrid detectors with 600 × 600 mm 2 active area is envisaged to upgrade COMPASS RICH-1 at CERN in 2016. [ABSTRACT FROM AUTHOR]

Silicon photomultipliers (SiPM) are candidates selected as the potential photodetector technology for the dual-radiator Ring-Imaging Cherenkov (dRICH) detector at the future Electron-Ion Collider (EIC). SiPM are cheap devices, highly efficient and insensitive to the high magnetic field at the expected location of the sensors in the experiment. On the other hand, SiPM are not radiation tolerant. Despite the integrated radiation level is expected to be moderate it should be tested whether single photon-counting capabilities and the increase in dark count rate can be kept under control to maintain the optimal dRICH detector performance across the years. The current status of the research for the EIC dRICH application and the first results on studies performed on a sample of commercial and prototype SiPM sensors are presented. [ABSTRACT FROM AUTHOR]

Since 1989 the radiocarbon dating lab has their own graphitization system for 14 C AMS dating but RICH (Royal Institute for Cultural Heritage) did not possess their own AMS and measurements were carried out in collaboration with other AMS facilities. In April 2013 the Micadas (Mini Carbon Dating System) AMS was installed at RICH in Brussels and after 1.5 year operation the high stability and performance of the Micadas can be demonstrated by repeated analyses of primary standard OXA II and secondary standards. Results of unknown samples measured on the RICH–Micadas and on other AMS systems are in good agreement. [ABSTRACT FROM AUTHOR]

We have investigated the response of a significant sample of Hamamatsu H8500 MultiAnode PhotoMultiplier Tubes (MAPMTs) as single photon detectors, in view of their use in a ring imaging Cherenkov counter for the CLAS12 spectrometer at the Thomas Jefferson National Accelerator Facility. For this, a laser working at 407.2 nm wavelength was employed. The sample is divided equally into standard window type, with a spectral response in the visible light region, and UV-enhanced window type MAPMTs. The studies confirm the suitability of these MAPMTs for single photon detection in such a Cherenkov imaging application. [ABSTRACT FROM AUTHOR]

Recent development of SiPMs makes them a promising candidate for replacement of photomultiplier tubes in Ring Imaging Cherenkov (RICH) counters. A commercially available 8×8 SiPM array, Hamamatsu MPPC S11834 with a rather low dark count rate, was tested as a single photon sensor in a RICH counter. To increase its overall geometrical acceptance, light concentrators were employed. The various factors that influence their efficiency are estimated and the results of measurements with polarized light are presented, showing a good agreement with a Monte Carlo study. [ABSTRACT FROM AUTHOR]

Wavelength-shifting (WLS) films were applied on UV-extended front windows of multianode photomultiplier tubes (MAPMTs) in order to increase the sensitivity of the MAPMTs at shorter wavelengths. The WLS material contained p-Terphenyl as photoactive component, which absorbs shorter wavelength photons ( < 300 nm ) and re-emits fluorescence photons around 350 nm, i.e., at the maximum of the PMTs׳ sensitivity. The films were applied by means of dip-coating and the film performance was studied with respect to quantum efficiency, film homogeneity, and crosstalk on the MAPMTs. Using WLS-film-covered MAPMTs in a gaseous Ring Imaging Cherenkov detector, the number of detected photoelectrons per ring increased by up to 21% in an in-beam test. [ABSTRACT FROM AUTHOR]

The main characteristics of the COMPASS experimental setup for physics with hadron beams are described. This setup was designed to perform exclusive measurements of processes with several charged and/or neutral particles in the final state. Making use of a large part of the apparatus that was previously built for spin structure studies with a muon beam, it also features a new target system as well as new or upgraded detectors. The hadron setup is able to operate at the high incident hadron flux available at CERN. It is characterised by large angular and momentum coverages, large and nearly flat acceptances, and good two and three-particle mass resolutions. In 2008 and 2009 it was successfully used with positive and negative hadron beams and with liquid hydrogen and solid nuclear targets. This paper describes the new and upgraded detectors and auxiliary equipment, outlines the reconstruction procedures used, and summarises the general performance of the setup. [ABSTRACT FROM AUTHOR]

We present the final results from a novel Cherenkov imaging detector called the Focusing DIRC (FDIRC). This detector was designed as a full-scale prototype of the particle identification system for the SuperB experiment [1], and comprises 1/12 of the SuperB barrel azimuthal coverage, with partial photodetector and electronics implementation. The prototype was tested in the SLAC Cosmic Ray Telescope which provided 3D tracking of cosmic muons with an angular resolution of ~1.5 mrad, a position resolution of 4–5 mm, a start time resolution of 70 ps, and muon tracks above ~2 GeV tagged using an iron range stack. The fused silica focusing photon camera was coupled to a full-size BaBar DIRC bar box and was read out, over part of the full coverage, by 12 Hamamatsu H8500 multi-anode photomultipliers (MaPMTs) providing 768 pixels. We used waveform digitizing electronics to read out the MaPMTs. We give a detailed description of our data analysis methods and point out limitations on the present performance. We present results that demonstrate some basic performance characteristics of this design, including (a) single photon Cherenkov angle resolutions with and without chromatic corrections, (b) signal-to-noise (S/N) ratio between the Cherenkov peak and background, which primarily consists of ambiguities of the possible photon paths from emission along the track to a given pixel, (c) dTOP=TOP measured – TOP expected resolutions (with TOP being the photon Time-of-Propagation in fused silica), and (d) performance of the detector in the presence of high-rate backgrounds. [ABSTRACT FROM AUTHOR]

Remote intracerebral haemorrhage (rICH) is defined as intracerebral haemorrhage (ICH) post thrombolysis in brain regions without visible ischaemic changes. There is uncertainty that clinical outcomes and risk factors for rICH are different to those for local ICH. We investigated the morbidity, mortality and factors associated with rICH. We hypothesised that a previous history of cerebral ischaemic events is associated with increased risk of rICH. We included consecutive acute ischaemic stroke patients from 2003 to 2012 who were treated with intravenous thrombolysis. Clinical data included demographics, stroke classification, vascular risk factors and laboratory results. Clinical outcome was defined by modified Rankin Scale (mRS) score at 3 months. Baseline and follow-up CT scans were analysed for all ICH, and further dichotomised to rICH and local ICH. Clinical outcomes between rICH and local ICH were compared after adjustment for confounding factors. Four hundred and two patients were included in the study. The median age was 71 (interquartile range 60–79) years, and 54% were male. ICH (local ICH and rICH) was detected in 21.6% (87/402) of all patients post thrombolysis. The incidence of rICH was 2.2% (9/402). Most rICH were classified as haemorrhagic infarct category 2 (HI2) ( p = 0.002). The proportion of patients with previous transient ischaemic attacks was significantly higher in the rICH group (33.33% versus 2.56%; odds ratio [OR] 18.75, 95% confidence interval [CI] 3.06–114.38; p = 0.007). The proportion of mRS scores 0–2 at 3 months was significantly higher in the rICH group (50% versus 28%; adjusted OR 10.469, 95%CI 1.474–74.338; p = 0.019). The 3 month mortality rate was 22.2% (2/9) in the rICH group and 36% (27/75) in the local ICH group (OR 0.53, 95%CI 0–2.51, p = 0.703). rICH was an infrequent complication after intravenous thrombolysis in our series. The clinical outcome of rICH was significantly better than local ICH. Of note, previous episodes of transient ischaemic attack were significantly higher in the rICH group, suggesting previous ischaemic injury as an underlying mechanism. [ABSTRACT FROM AUTHOR]

Photomultiplier tubes, in particular multianode photomultiplier tubes, are often used in current accelerator-based nuclear and particle physics experiments for spatially resolved detection of single photons. With increasing luminosity and harsh radiation background, the radiation hardness of these sensors plays an increasingly important role. In an extensive experimental study we have investigated the effects of neutron irradiation, using a fission neutron source, and energetic 60Co γ -irradiation on commercially available Hamamatsu H12700/H8500 MAPMTs. In addition, individual components were irradiated, such as their glass windows and voltage dividers. Additionally, a p -terphenyl based wavelength shifting coating, which can be applied on the MAPMT window to enhance the photon yield, was also tested for its radiation tolerance. [ABSTRACT FROM AUTHOR]

Particle identification system based on Focusing Aerogel RICH (FARICH) detector is considered as an option for the future experiments at the Super Charm-Tau Factory (Russia). We present the progress of FARICH R&D at the Budker Institute of Nuclear Physics. New samples of focusing 4-layer aerogels with maximal refractive index 1.065 were produced in 2020–2021. First beam test results with relativistic electrons demonstrate single photon resolution (SPR) of 9 ÷ 10 mrad. According to simulation results, the aerogels with such SPR are able to provide μ / π -separation at the level of more than 3 standard deviations for tracks with momentum 1.5 GeV/c. The first version of electronics to readout SiPM arrays based on TDC implemented on FPGA (FPGA-TDC) was developed and manufactured. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2009.04.004 Byline: Elizabeth A. MacDougall-Shackleton, Kathryn A. Stewart, Dominique A. Potvin, Erica Tennenhouse Abstract: Animal signals are often complex, raising the possibility that different aspects of a signal may convey different types of information. Birdsong, for example, may simultaneously advertise the singer's condition during early life (through song complexity), location of song learning (through local song structure) and current condition (through song output). Each of these aspects of song is behaviourally salient: females generally prefer complex over simple song, local over nonlocal song, and high over low rates of song output. We examined the degree to which these three components of song convey complementary versus redundant information, in eastern song sparrows, Melospiza melodia melodia. One measure of song complexity, syllable repertoire size, was positively related to syllable sharing with other birds in the local population. This finding suggests that these aspects convey somewhat redundant information and that local-sounding song may in part advertise song-learning ability. A second measure of song complexity, song repertoire size, was positively related to song output, despite the widely differing developmental timescales over which song complexity and output are thought to vary. Condition during early development may have carryover effects on adult condition; alternatively, complex singers may have most to gain from advertising this attractive signal. Finally, despite our finding that both syllable sharing and song output were related to song complexity, syllable sharing and song output were not themselves significantly correlated. Overall, the three ostensibly independent aspects of song investigated here appear to overlap substantially in the information they convey. Author Affiliation: Department of Biology, The University of Western Ontario, London, ON, Canada Article History: Received 24 October 2008; Revised 5 February 2009; Accepted 9 April 2009 Article Note: (miscellaneous) MS. number: A08-00699

In the period June 2015–September 2016 the LHC has delivered pp and Pb-Pb collisions respectively at √s=13 TeV and √ s NN =5.02 TeV for a total integrated luminosity in ALICE of 14 pb −1 . The High Momentum Particle IDentification detector (HMPID) is part of the ALICE experiment. It is based on seven Ring Imaging Cherenkov (RICH) modules, 1.3×1.3 m 2 each, with a proximity focusing geometry. The Cherenkov photon detection is achieved by pad segmented photocathodes, coated with 300 nm thick Caesium Iodide layer, installed in multiwire proportional chambers. Liquid C 6 F 14 (perfluorohexane) with n=1.2989 at λ=175 nm is used as Cherenkov radiator. The HMPID identifies with three sigma separation charged π and K in the momentum range 1–3 GeV/c and protons in the range 1.5–5 GeV/c. The scatter plots of the Cherenkov angle for both pp and Pb-Pb events are presented as preliminary Particle Identification (PID) performance. After the good results shown during 2010–2013, in this paper the HMPID performance in the period 2015–2016, with emphasis on the CsI quantum efficiency stability, are presented. Finally the perspectives of the detector operation in the period HL-LHC 2019–2022, are briefly discussed. [ABSTRACT FROM AUTHOR]

A real size prototype of the CBM RICH detector was tested in beam at CERN in November 2014 with new readout electronics. A detailed analysis of the timing characteristics of the readout chain will be presented in this article. Results of the time precision measurements for several subsets of all channels and the stability of the fine time calibration will be discussed. The obtained sub-nanosecond time precision allows also to investigate the effect on timing when using additional wavelength-shifting films on top of the MAPMT windows. [ABSTRACT FROM AUTHOR]

A small-size prototype of a new Ring Imaging Cherenkov (RICH) detector using for the first time pressurized C4F8O radiator gas and a photon detector consisting of MWPC equipped with a CsI photocathode has been built and tested at the PS accelerator at CERN. It contained all the functional elements of the detector proposed as Very High Momentum Particle Identification (VHMPID) upgrade for the ALICE experiment at LHC to provide charged hadron track-by-track identification in the momentum range starting from 5 potentially up to 25 GeV/c. In the paper the equipment and its elements are described and some characteristic test results are shown. [ABSTRACT FROM AUTHOR]

The characterization of the new Hamamatsu R 11265-103- M 64 multi-anode photomultiplier tube is presented. The sample available in our laboratory was tested and in particular the response to single photon was extensively studied. The gain, the anode uniformity and the dark current were measured. The tube behaviour in a longitudinal magnetic field up to 100 G was studied and the gain loss due to the ageing was quantified. The characteristics and performance of the photomultiplier tube make the R 11265-103- M 64 particularly tailored for an application in high energy physics experiments, such as in the LHCb Ring Imaging Cherenkov (RICH) detector at LHC. [ABSTRACT FROM AUTHOR]

The gaseous COMPASS RICH-1 detector uses two spherical mirror surfaces, segmented into 116 individual mirrors, to focus the Cherenkov photons onto the detector plane. Any mirror misalignment directly affects the detector resolution. The on-line Continuous Line Alignment and Monitoring (CLAM) photogrammetry-based method has been implemented to measure the alignment of individual mirrors which can be characterized by the center of curvature. The mirror wall reflects a regular grid of retroreflective strips placed inside the detector vessel. Then, the position of each mirror is determined from the image of the grid reflection. The images are collected by four cameras. Any small mirror misalignment results in changes of the grid lines’ positions in the image. The accuracy limits of the CLAM method were checked by laser interferometry and are below 0.1 mrad. [ABSTRACT FROM AUTHOR]

We present an indirect measurement of possible long term variations of the CsI quantum efficiency in solid state photocathodes in MWPC. This type of photon detectors has been used since 2001 in the Cherenkov Imaging detector RICH-1 of the COMPASS experiment at CERN SPS. Data from six years of COMPASS data taking are used to evaluate the mean number of detected photons per particle. The results do not indicate any severe CsI quantum efficiency ageing effect. [ABSTRACT FROM AUTHOR]

This paper presents recent progress in the development and mass production of large-area hydrophobic silica aerogels for use as radiators in the aerogel-based ring-imaging Cherenkov (A-RICH) counter, which will be installed in the forward end cap of the Belle II detector. The proximity-focusing A-RICH system is especially designed to identify charged kaons and pions. The refractive index of the installed aerogel Cherenkov radiators is approximately 1.05, and we aim for a separation capability exceeding 4 σ at momenta up to 4 GeV/ c . Large-area aerogel tiles (over 18×18×2 cm 3 ) were first fabricated in test productions by pin drying in addition to conventional methods. We proposed to fill the large end-cap region (area 3.5 m 2 ) with 124 water-jet-trimmed fan-shaped dual-layer-focusing aerogel combinations of different refractive indices (1.045 and 1.055). Guided by the test production results, we decided to manufacture aerogels by the conventional method and are currently proceeding with mass production. In an electron beam test undertaken at the DESY, we confirmed that the K / π separation capability of a prototype A-RICH counter exceeded 4 σ at 4 GeV/ c . [ABSTRACT FROM AUTHOR]