Cherenkov counter

Fig. 9. Experimental setup for observation of ultrarelativistic A2e a) - channel scheme p - internal proton beam, T - film target, F - polyester film,CL - collimators, H -horizontal magnetic field, C - plexiglas converter b) - magnet and detectors MP - poles of spectrometer magnet, VC - vacuum chamber, DC1, DC2 and DC3 - drift chambers, SI and S2 - scintillation counters, C - gas Cherenkov counters...

Charged particles were detected by the telescopes Ti and T2. The track coordinates were measured by drift chambers. The time interval between detector hits in Ti and T2 was measured by scintillation hodoscopes. Electrons and positrons were rejected by gas Cherenkov counters, and muons by scintillation... 

Fig. 15. Schematic top view of the DIRAC spectrometer. Moving from the target station toward the magnet there are four MicroStrip Gas Chambers (MSGC), two Scintillating Fibre Detectors (SFD) and an Ionization Hodoscope (IH). Located downstream from the dipole magnet, on each arm of the spectrometer, are 4 modules of Drift Chambers (DC), a Vertical and a Horizontal Hodoscope (VH, HH), a Cherenkov counter (C), a Preshower detector (PSh) and, behind an iron absorber, a Muon counter (Mu)...

Figure 4. Schematic arrangement of the TRACER balloon instrument. The nuclear charge Z of traversing cosmic-ray nuclei is determined with plastic scintillators. An acrylic Cherenkov counter determines their Lorentz factor 7 at low energies, and arrays of single-wire proportional tubes measure 7 from the relativistic rise in specific ionization, and from transition radiation signals.

Poelz G, RiethmueUer R (1982) Preparatitm of silica aerogel for Cherenkov counters. Nuc Instr Meth 195 491-503... 

Yokogawa H, Yokoyama M (1995) Hydrophobic silica aerogels. J Non-Cryst Solids 186 23-29 Kharzheev YN (2008) Use of silica aerogels in Cherenkov counters. Physics of Particles and Nuclei,... 

Buzykaev A. et al (1996) Project of aerogel cherenkov counters for KEDR, J. Nucl. Instr. and Meth. Phys. Res. A 379 453 56... 

In this section, examples of specifications of P-EW s hydrophobic sihca aerogel products are introduced and motivation and performance of a sihca aerogel Cherenkov counter are also introduced. The astronomical data collected in B-factory experiment in which hydrophobic silica aerogel was instaUed as a Cherenkov counter in BELLE lead to Makoto Kobayashi and Toshihide Maskawa winning the Nobel prize in 2008. 

The durabihty of silica aerogel for the moismre is very important when this material is used in the atmosphere. When a silica aerogel is used as a medium of a Cherenkov counter, the durability for the moisture, hydrophobicity, is essential because some large-scale... 

Figure 28.7 shows a typical model of a threshold-type Cherenkov counter. Silica aerogel is filled in a box to which photomultiplier tubes (PMTs) are attached. The refractive index of aerogel is set so that the Cherenkov light is emitted for pions but not for kaons [8,9]. In this way, it is known that kaon/pion/proton separation in the momentum region of 1.0-3.5 GeV/c is possible using aerogel with low refractive index such as 1.01-1.03. 

This type of IMS A Cherenkov counter module was tested using a 3.5 GeV/c negative pion beam at KEK [10]. TMSA with refractive index is 1.015 and two 2.5" PMTs were arranged. Typical pulse height distributions for 3.5 GeV/c pions and protons observed are... 

Figure 28.7. Schematic view of a typical threshold-type silica aerogel Cherenkov counter.

Figure 28.8. Pulse height spectra for 3.5 GeV/c pions (above threshold) and protons (below threshold) obtained by a single module of aerogel Cherenkov counter, in which n = 1.015 TMSA blocks were stacked.

Figure 28.9. Schematic view of a ring image Cherenkov counter using silica aerogel blocks.

A typical single threshold-type aerogel Cherenkov counter (ACC) module looks as shown in Figure 28.12. TMSA tiles are stacked in a thin aluminum box of approximate dimensions 120 x 120 x 120 mm. In order to detect the Cherenkov light effectively, two fine mesh-type PMTs are attached directly to the aerogels at both sides of the box. The inner surface of the box (except for the phototube windows) is lined with a diffuse reflector... 

Base Preamplifier Figure 28.12. Schematic drawing of a single module of TMSA s Cherenkov counter for BELLE. 

Figure 28.13. Arrangement of the TMSA s Cherenkov counters at the central part of BELLE detector.

TMSA has an additional feature for the realization of various kinds of Cherenkov counters. Because of blocks excellent hydrophobicity, it is possible to cut them by water-jet processing and secondarily to arrange them to the required shape or size of Cherenkov counter. Figure 28.17 shows the samples cut down from standard blocks by water-jet. The properties and hydrophobicity are not depreciating after the cut processing. 

Carlson P (1986) Aerogel Cherenkov counters construction principles and applications. Nucl lustrum Methods Phys Res Sect A248 110-117. 

Suda R, Watanabe M, Enomoto R, lijima T, Adachi I, Hattori H, Kuniya T, Ooba T, Sumiyoshi T, Yoshida (1998) Monte-Carlo simulation for aerogel Cherenkov counter. Nucl lustrum Methods Phys Res Sect A406 213-226. 

Sumiyoshi T, Adachi I, Enomoto R, lijima T, Suda R, Leaerogel Cherenkov counter fim the KEK B-factory experimmt. Nucl Instnnn Methods Hiys Res Sect A433 385 391. 

MacKenzie J D (1988) Applications of the sol-gel process. J Non-Cryst Solids 100 162—168 Adachi I, Sumiyoshi T, Hayashi K, lida N, Enomoto R, T sukada K, Suda R, Matsumoto S, Natori K, Y okoyama M, Yokogawa H (1995) Study of a threshold Cherenkov counter based on silica aerogels with low refractive index. Nucl Instr Meth Phys Res A, 335 390-398... 

Absorption In chemistry, the process by which one substance, such as a solid or liquid, takes up another substance, such as a liquid or gas, through minute pores or spaces between its molecules. In physics, the process in which the incident radiated energy is retained without reflection or transmission on passing through a medium ACC Aerogel Cherenkov Counter Acidity Acid strength... 

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