RICH Prototype Research Articles

AN ANALYSIS OF THE MYTHICAL PATTERNS IN ULYSSES FROM THE PERSPECTIVE OF ARCHETYPE THEORY

As one of the important creative themes of modern literature, mythology is constantly reiterated in the writings of modern writers. Through retelling, we can travel through the time tunnel and feel the poetic wisdom of our ancestors. The inherent characteristic of myth is symbolism, and at the same time, it has strong metaphor and inclusiveness, which has opened up an almost infinite space of meaning for modern writers. Mythology provides rich prototype resources for the plot structure framework of narrative works, and expresses the writer's unique creative perspective and aesthetic awareness. James Joyce was an outstanding modern novelist in the West in the 20th century, and he created unique mythological novels. Ulysses adopts the mythological prototype structure and uses the theme of the ancient hero Odysseus returning home, echoing the deep meaning of modern people's search for a spiritual home. This paper uses the theory of myth-prototype criticism and combines the theory of collective unconsciousness to explore the creation mode of Ulysses from the perspective of mythic archetype criticism, to explain how ancient myths and modern writers have a spiritual fit, and to further feel the uniqueness of Joyce's novels. Some artistic charm and the practical significance brought by Ulysses. Our era needs the spirit of exploration and courage left over from the early days of human society, and the connotation of archetypal criticism has positive ideological value to this day.

A novel fast-timing readout chain for LHCb RICH LS3 and prototype beam tests

The prompt Cherenkov radiation and focusing optics of the LHCb RICH detectors allow the prediction of the Cherenkov photon detection time from a given charged particle to within 10ps. Fast-timing information on the detected Cherenkov photons can therefore be used to significantly improve the particle identification (PID) performance and the signal-to-background ratio of the detectors. This concept is a cornerstone for the LHCb RICH detector upgrades and will ultimately allow the system to operate at a luminosity in excess of 1034cm−2s−1 during HL-LHC Run 5. A new electronic readout chain is proposed for the LHC Long Shutdown 3 (LS3, 2026-2028) using the FastRICH, a novel ASIC under development. The specifications for the FastRICH are discussed in the context of the LS3 enhancements and LHCb Upgrade II. The FastRICH will perform multi-channel single-photon discrimination, timestamp photons with 25 ps bin size, integrate closely with the LHCb optical link chipset and apply data-compression techniques. The detector will be capable of timestamping each photon with 150ps resolution dominated by the existing Multianode Photomultiplier Tube (MAPMT) transit-time spread. The new electronic readout chain introduces important timing and detector techniques ahead of the Upgrade II RICH system overhaul and the FastRICH has the flexibility to be coupled to sensors with better time resolution for HL-LHC Run 5. Simulation studies have demonstrated improvements in the hadronic PID performance during Run 4 using the FastRICH coupled to MAPMTs. A first version of the readout chain, based on the FastIC, a predecessor of the FastRICH, and a TDC-in-FPGA, has been studied using Cherenkov photons at the CERN SPS charged particle beam test facility.

Tests of the CBM Rich readout and Daq prototype

The CBM RICH detector is an integral component of the future CBM experiment at FAIR, providing efficient electron identification and pion suppression necessary for the measurement of rare dileptonic probes in heavy ion collisions. An overview of the CBM RICH readout and DAQ system prototype is given, consisting of the PADIWA preamplifier-discriminator board, the TDC-HUB board TRBv3, and DAQ and analysis code in the CbmRoot framework. The laboratory setup built for studying the timing characteristics of the readout chain and the analysis results obtained using the laboratory measurements are presented. The fine time calibration and inter-channel delay correction techniques and their implementation and effect are discussed.

Investigation into Cherenkov light scattering and refraction on aerogel surface

The work concerns the development of aerogel radiators for RICH detectors. Aerogel tiles with a refractive index of 1.05 were tested with a RICH prototype on the electron beam on the VEPP-4M collider. It has been shown that polishing with silk tissue yields good surface quality, the amount of light loss at this surface being about 5–7%. The Cherenkov angle resolution was measured for a tile in two conditions: with a clean exit face and with a polished exit face. The number of photons detected was 13.3 and 12.7 for the clean and polished surfaces, respectively. The Cherenkov angle resolution for the polished surface is 55% worse, which can be explained with the forward scattering on the polished surface. A tile with a crack inside was also tested. The experimental data show that the Cherenkov angle resolution is the same for tracks crossing the crack area and in a crack-free area.

Test of the CLAS12 RICH large-scale prototype in the direct proximity focusing configuration

A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c up to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Laboratory. The adopted solution foresees a novel hybrid optics design based on aerogel radiator, composite mirrors and high-packed and high-segmented photon detectors. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). We report here the results of the tests of a large scale prototype of the RICH detector performed with the hadron beam of the CERN T9 experimental hall for the direct detection configuration. The tests demonstrated that the proposed design provides the required pion-to-kaon rejection factor of 1:500 in the whole momentum range.

The RICH detector of the NA62 experiment at CERN

The NA62 experiment at CERN aims to measure the branching ratio of the ultra-rare charged kaon decay K+→π+νν¯ with a 10% accuracy and with a background contamination at the 10% level. Since the branching ratio of this decay is O(10−10), to fulfill such request one of the main backgrounds, the decay K+→μ+ν (BR~63%), must be suppressed by a rejection factor of 4×10−13 (assuming 10% signal acceptance). This can be partially accomplished using a combination of kinematical cuts (8×10−6) and the different power of penetration through matter of pions and muons (10−5). A further 5×10−3 suppression factor will be provided by a RICH detector, in a momentum range between 15 and 35GeV/c. The details of the RICH project as well as the results from test runs performed on a RICH prototype of the same length of the final detector will be presented. The current status of the construction and the description of the final readout and trigger electronics will also be reviewed.

Test of the Hamamatsu MPPC module S11834 as a RICH photon detector

In our previous studies, we have shown that silicon photo-multipliers can be used as single photon detectors in a RICH counter (Korpar et al., 2009, 2010 [1,2]). Their main advantage with respect to the classical photo-multiplier tubes is the operation in high magnetic fields, while their disadvantage is a relatively high dark count rate. Recently, Hamamatsu made commercially available sensors with a rather low dark count rate (≈0.1MHz/mm2) and with a larger active area, offering a possibility for a much better signal-to-noise ratio. We have designed, constructed and tested a module with Hamamatsu 8×8 channel S11834 MPPCs. To increase the geometric acceptance, light concentrators have been employed. In the present contribution we discuss the results of studies of the light concentrator design optimization and of the detector module response to fast light pulses. Also presented are the results of RICH prototype tests in a test beam.

R&D on high momentum particle identification with a pressurized Cherenkov radiator

We report on the R&D results for a Very High Momentum Particle Identification (VHMPID) detector, which was proposed to extend the charged hadron track-by-track identification in the momentum range from 5 to 25GeV/c in the ALICE experiment at CERN. It is a RICH detector with focusing geometry using pressurized perfluorobutane (C4F8O) as a Cherenkov radiator. A MWPC with a CsI photocathode was investigated as the baseline option for the photon detector. The results of beam tests performed on RICH prototypes using both liquid C6F14 radiator (in proximity focusing geometry for reference measurements) and pressurized C4F8O gaseous radiator will be shown in this paper. In addition, we present studies of a CsI based gaseous photon detector equipped with a MWPC having an adjustable anode–cathode gap, aiming at the optimization of the chamber layout and performance in the detection of single photoelectrons.

The Ring Imaging Cherenkov detector for the CBM-Experiment

The mission of the future Compressed Baryonic Matter experiment, to be operated at the FAIR facility at GSI, Darmstadt, is the exploration of the properties of super-dense nuclear matter. In particular, the search for in-medium modifications of hadrons, the study of the transition from dense hadronic matter to quark-gluon matter, and the location of a critical endpoint in the phase diagram of strongly interacting matter are the principal physics goals of CBM. Detailed measurements of di-leptons and open charm probes are hoped to shed light to the existence of such effects.The Ring Imaging Cherenkov detector of CBM aims at a clean and efficient electron identification. It is foreseen to have CO2 as radiator gas and to be equipped with Hamamatsu multi-anode photomultiplier tubes. Herewith we present selected results of R&D studies and beam test measurements of the RICH prototype performed in October 2011 at the CERN/PS with negatively charged particles.

First observation of Cherenkov rings with a large area CsI-TGEM-based RICH prototype

We have built a RICH detector prototype consisting of a liquid C6F14 radiator and six triple Thick Gaseous Electron Multipliers (TGEMs), each of them having an active area of 10×10cm2. One triple TGEM has been placed behind the liquid radiator in order to detect the beam particles, whereas the other five have been positioned around the central one at a distance to collect the Cherenkov photons. The upstream electrode of each of the TGEM stacks has been coated with a 0.4μm thick CsI layer.In this paper, we will present the results from a series of laboratory tests performed with this prototype carried out using UV light, 6keV photons from 55Fe and electrons from 90Sr as well as recent results of tests with a beam of charged pions where for the first time Cherenkov Ring images have been successfully recorded with TGEM photodetectors. The achieved results prove the feasibility of building Cherenkov detector based on CsI coated TGEMs.

The NA62 RICH detector

The NA62 RICH must separate charged pions from muons in a 15–35 GeV/ c momentum range. The detector will have a 17 m long, 4 m wide cylindrical vessel, filled with neon at an atmospheric pressure. A mosaic of 20 mirrors, with 17 m focal length will be placed at the downstream end of the vessel while 2000 single anode photomultipliers will be placed at the upstream part. Two test beams were held at CERN in 2007 and 2009 with a RICH prototype. A muon suppression factor greater than 100 was validated.

Pion–Muon separation with a RICH prototype for the NA62 experiment

The NA62 experiment at CERN, aimed to measure K+→π+νν¯ branching fraction (O(10−10)), relies on a Neon based RICH detector for π/μ separation, time measurement and level 0 trigger. The experimental requirements for this detector are: a muon contamination in pion samples lower than 5×10−3 in the momentum range 15–35GeV/c and a time resolution on the charged track better than 100ps. A prototype of such a detector was built and tested in 2009; it consists of a full length (≈18m) Ne filled vessel equipped with a spherical mirror and 414 PMs on its focal plane, located about 17m upstream of the mirror. This prototype was tested at CERN SPS on a positive hadron beam, in the required momentum range, to measure the π/μ separation and to confirm the time resolution obtained with a previous prototype; the μ misidentification probability is about 0.7% and the time resolution is better than 100ps in the whole momentum range.

Study of 144-channel multi-anode hybrid avalanche photo-detector for the Belle RICH counter

A new hybrid avalanche photo-detector has been developed for the Belle RICH counter. The basic features of this device were examined with and without a magnetic field. By constructing a RICH prototype counter using 6 photo-detectors, we carried out a test beam experiment to confirm the performance. We obtained a single photon Cherenkov angle resolution of 12.8mrad with 4.6 photo-electrons in our experimental setup, demonstrating that 4σπ/K separation at 4GeV/c was achieved.

A multichannel compact readout system for single photon detection: Design and performances

Optimal exploitation of Multi Anode PhotoMultiplier Tubes (MAPMT) as imaging devices requires the acquisition of a large number of independent channels; despite the rather wide demand, on-the-shelf electronics for this purpose does not exist. A compact independent channel readout system for an array of MAPMTs has been developed and tested [1,2]. The system can handle up to 4096 independent channels, covering an area of about 20 × 20 cm 2 with pixel size of 3 × 3 mm 2 , using Hamamatsu H-9500 devices. The front-end is based on a 64 channels VLSI custom chip called MAROC, developed by IN2P3 Orsay (France) group, controlled by means of a Field Programmable Gate Array (FPGA) which implements configuration, triggering and data conversion controls. Up to 64 front-end cards can be housed in four backplanes and a central unit collects data from all of them, communicating with a control Personal Computer (PC) using an high speed USB 2.0 connection. A complete system has been built and tested. Eight Flat MAPMTs (256 anodes Hamamatsu H-9500) have been arranged on a boundary of a 3 × 3 matrix for a grand total of 2048 channels. This detector has been used to verify the performances of a focusing aerogel RICH prototype using an electron beam at the Frascati (Rome) INFN National Laboratory Beam Test Facility (BTF) during the last week of January 2009. Data analysis is ongoing: the first results are encouraging, showing that the Cherenkov rings are well identified by this system.

Test Beam Data Analysis and Simulation of a RICH Prototype for the NA62 Experiment

The NA62 experiment at CERN, aimed to measure K+ rarr pi+nunumacr branching fraction (O(10-11)) , relies on a gas based RICH detector for pi/mu separation and level 0 trigger. The experiment requirements for this detector are mainly a time resolution better than 100 ps and a muon rejection better than 5 times 10-3 in the momentum range 15-35 GeV/c. A first prototype of such a detector has been built and tested in 2007; it is a full length (18 m) Ne filled vessel equipped with a spherical mirror and 96 PMs on its focal plane, ap17 m upstream of the mirror. This prototype has been tested at CERN SPS on a 200 GeV/c pion beam mainly as a first check of its time resolution and of the light collection technique; the time resolution has been found to be about 65 ps, and the light collection, i.e. the number of hit PMs per ring, fairly as expected.

Construction and test of a RICH prototype for the NA62 experiment

A RICH prototype has been constructed and tested. The detector was cylindrical, 17 m long and 60 cm diameter, filled with neon gas at atmospheric pressure. A spherical mirror with 17 m focal length was used and 96 photomultipliers were placed in the mirror focal plane. The prototype was exposed to a 200 GeV / c momentum negative beam derived from the CERN SPS in the 2007 fall. The performances of the detector in terms of Cherenkov angle resolution, number of photoelectrons and time resolution are presented.

In-beam tests of the AMS RICH prototype with [formula omitted] secondary ions

A prototype of the AMS Cherenkov imager (RICH) has been tested by means of a low intensity 20 GeV/c per nucleon ion beam coming from the fragmentation of a primary beam of Pb ions. Data have been collected for charges 1< Z<∼45 in various beam conditions and using different radiators. The charge Z and velocity β resolution have been of the prototype investigated.

Aging of large-area CsI photocathodes for the ALICE HMPID prototypes

The ALICE High-Momentum Particle IDentification RICH detector is equipped with CsI photocathodes (PCs) in a MWPC for the detection of Cherenkov photons. The long-term operational experience with large-area CsI PCs is described. The RICH prototypes have shown a very high stability of operation and performance at a gain of 10 5 and with rates up to 2×10 4 cm −2 s −1. When exposure to air is avoided, no degradation of the CsI quantum efficiency has been observed on PCs periodically exposed to test beams over 7 years, corresponding to local integrated charge densities of ∼1 mC/cm 2. The results of limited exposures to oxygen and humidity are also presented.

The AMS RICH detector

The Ring Imaging Cerenkov Counter (RICH) of the AMS detector is presented. The expected capabilities of the counter are discussed and the basic performances of a RICH prototype are shown.

Recognition of Cherenkov patterns in high multiplicity environments

An algorithm for the recognition of Cherenkov patterns based on the Hough Transform Method is presented. It basically consists in a mapping of the pad coordinate space directly to the Cherenkov angle parameter space with a crucial increase of performance in the treatment of different pattern shapes and amount of background.The method has been developed in the framework of the ALICE experiment at CERN, for the analysis of data taken with the High Momentum Particle Identification Detector RICH prototype in the test beam.