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
π
/
K
separation at the upgraded Belle detector is discussed.
Study of highly transparent silica aerogel as a RICH radiator Adachi, I.; Fratina, S.; Fukushima, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2005, Letnik:
553, Številka:
1
Journal Article
Recenzirano
We have developed silica aerogel to be employed as a RICH radiator in the Belle PID upgrade. For this purpose, new aerogel sample with a higher refractive index (
n) of
∼
1.05
was successfully ...produced while keeping the hydrophobic feature. In this novel technique, a new solvent was introduced in the first step of the sol–gel process so as to avoid a deterioration of the optical quality, even for
n greater than 1.03. Based on this procedure, the transmission length was obtained to be more than 40 mm at 400
nm wave length, which was twice longer than before, for samples of
∼
100
×
100
×
10
mm
3
size. In this article, the results of the new aerogel production will be shown together with some design considerations for the RICH radiator.
A proximity focusing ring imaging Cherenkov detector using aerogel as the radiator has been studied for upgrading the Belle detector at the KEK-B-factory. We constructed a prototype Cherenkov counter ...using a 4×4 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
π2 beam line in November, 2002. To evaluate systematically the performance of the detector, tests were carried out with various aerogel samples using pion beams with momenta between 0.5 and
4
GeV/c
. The typical angular resolution was around
14
mrad
, and the average number of detected photoelectrons was around 6. We expect that pions and kaons can be separated at a 4
σ level at
4
GeV/c
.
An upgrade of the particle identification system of the Belle detector is envisaged. In the search for an optimal photon detector, the performance of the Burle 85011 64-anode, multichannel plate PMT ...has been tested. The Cherenkov angle resolution and photon yield have been measured with pion beams at KEK, while the position and incident angle dependence of surface sensitivity have been measured on the bench.
RICH with multiple aerogel layers of different refractive index Korpar, S.; Adachi, I.; Fratina, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2005, Letnik:
553, Številka:
1
Journal Article
Recenzirano
A proximity focusing ring imaging Cherenkov detector with multiple aerogel radiator layers is studied. In situations where limited space is available and a compact RICH detector is required, the use ...of a nonhomogeneous, multiple refractive index radiator offers a possibility for improving the resolution. Experimental investigations of the relevant parameters, i.e. single photon Cherenkov angle uncertainty and number of detected photons per ring, are presented for different aerogel radiator configurations. The results are promising and appear to satisfy the requirements for the forthcoming upgrade of the particle identification system of the Belle detector.
Using aerogel as radiator and 64-channel flat panel multi-anode PMTs (Hamamatsu H8500) for photon detection, a proximity focusing Cherenkov ring imaging detector has been constructed and tested in ...the KEK
π
2
beam. The single photon resolution obtained in the tests (typically around 14
mrad) is well approximated by estimates of contributions from pixel size and emission point uncertainty. The number of detected photons per Cherenkov ring, typically about 6 for a 2
cm thick aerogel radiator tile, is in good agreement with estimates based on aerogel and detector characteristics. The detector allows a very efficient separation of kaons and pions at
4
GeV
/
c
.
The cross section for e(+)e(-)-->pi(+)pi(-)J/psi between 3.8 and 5.5 GeV/c(2) is measured using a 548 fb(-1) data sample collected on or near the Upsilon(4S) resonance with the Belle detector at ...KEKB. A peak near 4.25 GeV/c(2), corresponding to the so called Y(4260), is observed. In addition, there is another cluster of events at around 4.05 GeV/c(2). A fit using two interfering Breit-Wigner shapes describes the data better than one that uses only the Y(4260), especially for the lower-mass side of the 4.25 GeV enhancement.
Studies of a proximity focusing RICH with aerogel radiator Matsumoto, T.; Korpar, S.; Adachi, I. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2004, Letnik:
518, Številka:
1
Journal Article
Recenzirano
A proximity focusing ring imaging Cherenkov detector using aerogel as the radiator is studied for the upgrade of the Belle detector at KEK-B-factory. The second beam test of the detector was carried ...out using the recently introduced flat-panel PMTs (Hamamatsu H8500) and newly developed aerogel samples having better transmission length. We observe Cherenkov rings with a single photon resolution of about
14
mrad
, and typically on average 6 detected photons per ring. The results show that such a detector is a promising step in R&D for upgrading the Belle spectrometer.
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