A novel type of proximity focusing RICH counter with multiple refractive index aerogel radiator
T. Iijima, S. Korpar, I. Adachi, S. Fratina, T. Fukushima, A. Gorisek, H. Kawai, M. Konishi, Y. Kozakai, P. Krizan, T. Matsumoto, Y. Mazuka, S. Nishida, S. Ogaw… 展开作者
T. Iijima, S. Korpar, I. Adachi, S. Fratina, T. Fukushima, A. Gorisek, H. Kawai, M. Konishi, Y. Kozakai, P. Krizan, T. Matsumoto, Y. Mazuka, S. Nishida, S. Ogawa, S. Ohtake, R. Pestotnik, S. Saitoh, T. Seki, T. Sumiyoshi, Y. Uchida, Y. Unno, S. Yamamoto
A proximity focusing ring imaging Cherenkov detector, with the radiator consisting of two or more aerogel layers of different refractive indices, has been tested in 1-4 GeV/c pion beams at KEK. Essentially, a multiple refractive index aerogel radiator allows for an increase in Cherenkov photon yield on account of the increase in overall radiator thickness, while avoiding the simultaneous degradation in single photon angular resolution associated with the increased uncertainty of the emission point. With the refractive index of consecutive layers suitably increasing in the downstream direction, one may achieve overlapping of the Cherenkov rings from a single charged particle. In the opposite case of decreasing refractive index, one may obtain well separated rings. In the former combination an approximately 40% increase in photon yield is accompanied with just a minor degradation in single photon angular resolution. The impact of this improvement on the pion/kaon separation at the upgraded Belle detector is discussed.
The use of a nonhomogeneous aerogel radiator, i.e. one consisting of layers with different refractive indices, has been shown to improve the resolution of the Cherenkov angle measured with a proximity focusing RICH detector. In order to obtain further information on the performance of such a detector, a simple model has been used to calculate the resolution and search for optimal radiator parameters.
A proximity focusing ring imaging Cherenkov detector using aerogel as the radiator has been studied for an upgrade of the Belle detector at the KEK-B-factory. We constructed a prototype Cherenkov counter using a 4 x 4 array of 64-channel flat-panel multi-anode PMTs (Hamamatsu H8500) with a large effective area. The aerogel samples were made with a new technique to obtain a higher transmission length at a high refractive index (n=1.05). Multi-channel PMTs are read-out with analog memory chips. The detector was tested at the KEK-PS pi2 beam line in November, 2002. To evaluate systematically the …
In this paper, we present recent progress in the development of hydrophobic silica aerogel as a Cherenkov radiator. In addition to the conventional method, the recently developed pin-drying method for producing high-refractive-index aerogels with high transparency was studied in detail. Optical qualities and large tile handling for crack-free aerogels were investigated. Sufficient photons were detected from high-performance aerogels in a beam test.
The construction and use of a dual radiator Ring Imaging Cerenkov(RICH) detector is described. This instrument was developed for the HERMES experiment at DESY which emphasizes measurements of semi-inclusive deep-inelastic scattering. It provides particle identification for pions, kaons, and protons in the momentum range from 2 to 15 GeV, which is essential to these studies. The instrument uses two radiators, C4F10, a heavy fluorocarbon gas, and a wall of silica aerogel tiles. The use of aerogel in a RICH detector has only recently become possible with the development of clear, large homogeneou…
We present optical and X-ray radiographical characterization of silica aerogels with refractive index from 1.05 to 1.07 for a Cherenkov radiator. A novel pin-drying method enables us to produce highly transparent hydrophobic aerogels with high refractive index by shrinking wet-gels. In order to investigate the uniformity in the density (i.e., refractive index) of an individual aerogel monolith, we use the laser Fraunhofer method, an X-ray absorption technique, and Cherenkov imaging by a ring imaging Cherenkov detector in a beam test. We observed an increase in density at the edge of the aeroge…
We report recent progress in the development of large-area hydrophobic silica aerogels for use as radiators in the aerogel-based ring-imaging Cherenkov (A-RICH) counter to be installed in the forward end cap of the Belle II detector, which is currently being upgraded at the High Energy Accelerator Research Organization (KEK), Japan. The production of approximately 450 aerogel tiles with refractive indices of either 1.045 or 1.055 was completed in May, 2014, and the tiles are now undergoing optical characterization. Installation of the aerogels was tested by installing them into a partial mock-…
This study presents the development of large-area (18 $\times $ 18 $\times $ 2 cm$^3$), high refractive index ($n \sim $1.05) hydrophobic silica aerogel tiles for use as Cherenkov radiators. These transparent aerogel tiles will be installed in a Cherenkov detector for the next-generation accelerator-based particle physics experiment Belle II, to be performed at the High Energy Accelerator Research Organization (KEK) in Japan. Cracking has been eliminated from the prototype aerogel tiles by improving the supercritical carbon dioxide (scCO$_2$) extraction procedure when drying the wet gel tiles.…
This paper presents recent progress in the development and mass production of large-area hydrophobic silica aerogels for use as radiators in the aerogel-based ring-imaging Cherenkov (A-RICH) counter, which will be installed in the forward end cap of the Belle II detector. The proximity-focusing A-RICH system is especially designed to identify charged kaons and pions. The refractive index of the installed aerogel Cherenkov radiators is approximately 1.05, and we aim for a separation capability exceeding 4$σ$ at momenta up to 4 GeV/$c$. Large-area aerogel tiles (over 18 $\times $ 18 $\times $ 2 …
This paper reports the successful fabrication of silica aerogel Cherenkov radiators produced in the first batches from a 96-tile mass production performed using pin-drying technique in our laboratory. The aerogels are to be used in a ring-imaging Cherenkov detector in the spectrometer of a planned balloon-borne cosmic-ray observation program, HELIX (High Energy Light Isotope eXperiment). A total of 36 transparent, hydrophobic aerogel tiles with a high refractive index of 1.16 and dimensions of 10 cm $\times $ 10 cm $\times $ 1 cm will be chosen as the flight radiators. Thus far, 40 out of the …
New highly transparent, hydrophobic silica aerogels with refractive indices of 1.01 to 1.07 have been produced by Aspen Aerogels, Inc., and select tiles have been tested using an electron beam at the DESY, Hamburg facility. A diffusively-reflective threshold Cerenkov counter was designed and constructed for the purpose of evaluating the aerogels, and can accommodate aerogel tile areas of up to 20 cm by 20 cm. Measurements of the performance of the counter using the new aerogels as Cerenkov radiators are given in terms of photoelectron yields and a figure of merit.
This paper proposes a new X-ray radiographic technique for measuring density uniformity of silica aerogels used as radiator in proximity-focusing ring-imaging Cherenkov detectors. To obtain high performance in a large-area detector, a key characteristic of radiator is the density (i.e. refractive index) uniformity of an individual aerogel monolith. At a refractive index of n = 1.05, our requirement for the refractive index uniformity in the transverse plane direction of an aerogel tile is |δ(n - 1)/(n - 1)| < 4% in a focusing dual layer radiator (with different refractive indices) scheme. We a…
This study presents the development of hydrophobic silica aerogel for use as a radiator in threshold-type Cherenkov counters. These counters are to be used for separating positrons and positive muons produced by kaon decay in the J-PARC TREK/E36 experiment. We chose to employ aerogel with a refractive index of 1.08 to identify charged particles with momenta of approximately 240 MeV/$c$, and the radiator block shape was designed with a trapezoidal cross-section to fit the barrel region surrounding the kaon stopping target in the center of the TREK/E36 detector system. Including spares, we obtai…
On peculiarities of the annealing process for highly transparent silica-based aerogel tiles manufactured in Novosibirsk
Budker Institute of Nuclear Physics（布德克尔核物理研究所）；Novosibirsk State Technical University（新西伯利亚国立技术大学）；Boreskov Institute of Catalysis（博列斯科夫催化研究所）；Novosibirsk State University（新西伯利亚国立大学）
We have succeeded in developing hydrophobic silica aerogels over a wide range of densities (i.e. refractive indices). A pinhole drying method was invented to make possible producing highly transparent aerogels with entirely new region of refractive indices of 1.06-1.26. Obtained aerogels are more transparent than conventional ones, and the refractive index is well controlled in the pinhole drying process. A test beam experiment was carried out in order to evaluate the performance of the pinhole-dried aerogels as a Cherenkov radiator. A clear Cherenkov ring was successfully observed by a ring i…
Options for RICH detectors based on silica aerogels for the high-momentum range
Budker Institute of Nuclear Physics（布德刻尔核物理研究所）；Novosibirsk State Technical University（新西伯利亚国立技术大学）；Novosibirsk State University（新西伯利亚国立大学）；Boreskov Institute of Catalysis（博列斯科夫催化研究所）
We present herein a characterization of a standard method used at the High Energy Accelerator Research Organization (KEK) to produce hydrophobic silica aerogels and expand this method to obtain a wide range of refractive index (n = 1.006-1.14). We describe in detail the entire production process and explain the methods used to measure the characteristic parameters of aerogels, namely the refractive index, transmittance, and density. We use a small-angle X-ray scattering (SAXS) technique to relate the transparency to the fine structure of aerogels.
This study presents the advancement in hydrophobic silica aerogel development for use as Cherenkov radiators and muonium production targets. These devices are scheduled for use in several particle- and nuclear-physics experiments that are planned in the near future at the Japan Proton Accelerator Research Complex. Our conventional method to produce aerogel tiles with an intermediate index of refraction of approximately 1.05 is extended so that we can now produce aerogel tiles with lower indices of refraction (i.e., 1.03-1.04) and higher indices of refraction (i.e., 1.075-1.08); each with excel…
Hadronic reactions producing strange quarks such as exclusive or semi-inclusive kaon production, play an important role in studies of hadron structure and the dynamics that bind the most basic elements of nuclear physics. The small-angle capability of the new Super High Momentum Spectrometer (SHMS) in Hall C, coupled with its high momentum reach - up to the anticipated 11-GeV beam energy in Hall C - and coincidence capability with the well-understood High Momentum Spectrometer, will allow for probes of such hadron structure involving strangeness down to the smallest distance scales to date. To…
The NA62 RICH detector is used for the separation of pions and muons in the momentum range 15 -- 35 GeV/c and is expected to provide a muon suppression factor better than $10^{-2}$. A prototype of the final detector equipped with about 400 PMs (RICH-400 prototype) was built and tested in a dedicated run in 2009. The $π-μ$ separation was tested, as well as the effect of the pollution of the neon radiator with different amounts of oxygen and CO_2. The $μ$ misidentification probability is about 0.7% and the time resolution better than 100 ps in the whole momentum range. We did not observe any abs…
Simulation Study for Particle Identification with the dRICH of the ePIC Experiment at the EIC
INFN Sezione di Trieste（意大利国家核物理研究所的里雅斯特分部）；University of Trieste（的里雅斯特大学）；INFN Sezione di Ferrara（意大利国家核物理研究所费拉拉分部）；INFN Laboratori Nazionali di Frascati, Gruppo Collegato di Cosenza（意大利国家核物理研究所弗拉斯卡蒂实验室科森扎协作组）；University of Cosenza（科森扎大学）；University of Salerno（萨莱诺大学）；INFN Sezione di Napoli, Gruppo Collegato di Salerno（意大利国家核物理研究所那不勒斯分部萨莱诺协作组）；INFN Sezione di Genova（意大利国家核物理研究所热那亚分部）；INFN Laboratori Nazionali del Sud（意大利国家核物理研究所南部实验室）；Brookheav National Laboratory（布鲁克海文国家实验室）；Ramaiah University（拉马西亚大学）；Duke University（杜克大学）
The Aerogel Ring Imaging Cherenkov (ARICH) counter serves as a particle identification device in the forward end-cap region of the Belle II spectrometer. It is capable of identifying pions and kaons with momenta up to $4 \, {\rm GeV}/c$ by detecting Cherenkov photons emitted in the silica aerogel radiator. After the detector alignment and calibration of the probability density function, we evaluate the performance of the ARICH counter using early beam collision data. Event samples of $D^{\ast +} \to D^0 π^+ (D^0 \to K^-π^+)$ were used to determine the $π(K)$ efficiency and the $K(π)$ misidenti…
We have developed a new type of particle identification device, called an Aerogel Ring Imaging Cherenkov (ARICH) counter, for the Belle II experiment. It uses silica aerogel tiles as Cherenkov radiators. For detection of Cherenkov photons, Hybrid Avalanche Photo-Detectors (HAPDs) are used. The designed HAPD has a high sensitivity to single photons under a strong magnetic field. We have confirmed that the HAPD provides high efficiency for single-photon detection even after exposure to neutron and gamma-ray radiation that exceeds the levels expected in the 10-year Belle II operation. In order to…
We report on the design and commissioning of two silica aerogel Cherenkov detectors with different refractive indices. In particular, extraordinary performance in terms of the number of detected photoelectrons was achieved through an appropriate choice of PMT type and reflector, along with some design considerations. After four years of operation, the number of detected photoelectrons was found to be noticeably reduced in both detectors as a result of contamination, yellowing, of the aerogel material. Along with the details of the set-up, we illustrate the characteristics of the detectors duri…
Cerenkov technology is often the optimal choice for particle identification in high energy particle collision applications. Typically, the most challenging regime is at high pseudorapidity (forward) where particle identification must perform well at high high laboratory momenta. For the upcoming Electron Ion Collider (EIC), the physics goals require hadron ($π$, K, p) identification up to $\sim$~50 GeV/c. In this region Cerenkov Ring-Imaging is the most viable solution.\newline The speed of light in a radiator medium is inversely proportional to the refractive index. Hence, for PID reaching ou…
In both particle physics and muon applications, a high-resolution muon momentum measurement capability plays a significant role not only in providing valuable information on the properties of subatomic particles but also in improving the utilizability of cosmic ray muons. Typically, muon momentum is measured by reconstructing a curved muon path using a strong magnetic field and muon trackers. Alternatively, a time-of-flight and Cherenkov ring imager are less frequently applied, especially when there is a need to avoid a magnetic field. However, measurement resolution is much less than that of …
Beam test studies for a SiPM-based RICH detector prototype for the future ALICE~3 experiment
Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Bari（意大利国家核物理研究所巴里分部）；Dipartimento di Fisica dell’Università e del Politecnico di Bari（巴里大学与理工大学物理系）；CERN, the European Organization for Nuclear Research（欧洲核子研究中心）；Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México（墨西哥国立自治大学核科学研究所）
In both particle physics and cosmic ray muon applications, a high-resolution muon momentum measurement capability plays a significant role not only in providing valuable information on the properties of subatomic particles but also in improving the utilizability of muons. Currently, muon momentum is estimated by reconstructing the muon path using a strong magnetic field and muon trackers. Alternatively, time-of-flight or multiple Coulomb scattering techniques are less frequently applied, especially when there is a need to avoid using a magnetic field. However, the measurement resolution is muc…
Efficient and precise Cherenkov-based charged particle timing using SiPMs
Istituto Nazionale di Fisica Nucleare, Sezione di Bari（意大利国家核物理研究所巴里分部）；CERN, the European Organization for Nuclear Research（欧洲核子研究中心）；Dipartimento di Fisica “M. Merlin” dell’Università e del Politecnico di Bari（巴里大学与理工大学M. Merlin物理学系）
Development of a Cherenkov-Based Time-of-Flight Detector Using Silicon Photomultipliers
Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Bari（意大利国家核物理研究所巴里分部）；CERN, European Organization for Nuclear Research（欧洲核子研究组织（CERN））；Dipartimento di Fisica dell’Università e del Politecnico di Bari（巴里大学与理工大学物理系）
A Cherenkov detector based on an array of five lead fluoride ($β$-PbF$_2$) crystals of size 30 mm$\times$30 mm$\times$160 mm read out by reverse-type avalanche photodiodes (APD's) of active area 10 mm$\times$10 mm was used to measure the flux of secondary particles emerging from the annihilation of pulsed beams of antiprotons at the Antiproton Decelerator of CERN. We compared the relative photon yields of radiators made of $β$-PbF$_2$, fused silica, UV-transparent acrylic, lead glass, and a lead-free, high-refractive-index glass. Some {\it p-i-n} photodiodes were also used for the readout, but…
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…
