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The components of the SLD barrel Cerenkov Ring Imaging Detector (CRID) are now built and are being installed. We report on tests of these, including tests of the fiber optic calibration system, detailed studies of electron drift paths on production drift boxes and detectors, tests of the dynamic gating system and its effect on drift path distortions due to space-charge, and a measurement of the electron lifetime in a production drift box. In addition, we report on the UV transmission of recirculated liquid C{sub 6}F{sub 14} and on the effects of CRID construction materials on electron lifetime. 9 refs., 11 figs.

3D streamer image in a resistive plate counter (RPC) were taken by using a glass RPC, an image intensifier and a CCD camera. Observations were simultaneously made for self-discharge in top and side view, operated in the streamer mode with various gas mixtures(Ar/butane/HFC134a). The analysis of the streamer image might be useful for us to design the pickup strip width for the readout. We report on a shape of the streamer in the top and side view as a function of gas mixing ratio.

Resistive plate chamber (RPC) has attracted high-energy and cosmic-ray experiment since its introduction in early 1980's because of high efficiency, good time resolution, tracking capability and low cost. From these features, RPCs have been chosen as the muon detector for Belle experiment at KEK. The RPCs have two operation mode; avalanche and streamer mode. The avalanche mode has an advantage that it offers in terms of rate capability to compare with the streamer mode. But, the streamer mode is still preferred for high-energy experiment, mainly for its characteristics of giving large and saturated signal that makes the front-end electronics simple and the experiment operation easy. From this point of view, we have to study the rate capability of the streamer for a glass RPC with nitrogen laser beam. Furthermore, we are going to study the fundamental gas properties of streamer, drift velocity, diffusion, and electron attachment in the glass RPC. In this conference, we report the preliminary results of the rate capability of the glass RPC operated in streamer mode with nitrogen laser beam. The results provide us more knowledge of the rate capability for the streamer mode operation.

The primary purpose in the Belle experiment at the asymmetric-energy e/sup =/e/sup -/ collider at the High-Energy Accelerator Research Organization (KEK B factory) is the measurement of charge conjugation and parity (CP) violation in B meson decays. The K/sub L/ mesons and muons (KLM) detector was designed to identify K/sub L/'s and muons in this experiment. Since October 2001, the luminosity in the KEK B accelerator has been remarkably improved. The data on B meson decay are successfully collected in the Belle detector. In contrast with the high luminosity operations of the accelerator, however, the high background rate leading to a lower detection efficiency has been observed in the endcap KLM detector. For present and future high luminosity operations, we have to identify the background source and consider the shielding. To identify the background source, the background data sampled from e/sup +/e/sup -//spl rarr//spl mu//sup +//spl mu//sup -/ events were investigated and the simulations of the sensitivity of the endcap KLM detector to neutrons and /spl gamma/'s as the background sources were performed using the Geant4 simulation toolkit. The comparisons of the simulations with the experimental data are presented.

We present the results of an extensive study of the response of TMS and TMG for particle detector application. The energy resolutions of 976 keV conversion electrons from a /sup 207/Bi source are measured in a gridded ionization chamber filled with TMS (tetramethylsilane) and TMG (tetramethylgermanium), and are found to be about 5.7 and 5.5% (rms), respectively. We also deduce a simple method of estimating the electron lifetime using a gridded ionization chamber. The free-ion yield and electron lifetime for these liquids are estimated by this simple method to be 2.64, 2.78 and 16.89 /spl mu/s, 15.40 /spl mu/s, respectively. The radiation damage of both liquids is examined by measuring the electron lifetime as a function of accumulated radiation dose in a parallel plate ionization chamber. The electron lifetime for the damaged liquid almost recovers to its initial value after repeating the purification. Also, we present preliminary results of the investigation of recombination light from a /sup 241/Am source in TMG, which directly affects the charge collection for the ionization.

The free ion yields from /sup 207/Bi conversion electrons were measured as a function of applied electric field using ionization chambers filled with tetramethylsilane (TMS) and tetramethylgermanium (TMG). The distributions for thermalization lengths of electrons were calculated by using Gaussian and exponential forms. The total free ion yields considering the impurity effect in liquid, and the thermalization lengths of electrons in TMS and TMG were determined to be 3.35+or-0.49, 3.42+or-0.56 and 165+or-18 AA, 185+or-24 AA, respectively. >

We present the Cherenkov Ring Imaging Detector in the endcap regions of the SLD detector and report on initial performance during the 1993 and 1994 runs at the SLC. The endcap CRID was completed and commissioned in 1993 and is fully operational for the 1994 run. First Cherenkov rings have been observed. The endcap CRID detectors and fluid systems are described and initial operational experience is discussed. >

Summary form only given. The SLAC Large Detector (SLD) barrel Cerenkov ring imaging detector (CRID) is now complete and has participated in SLD data runs. Performance tests of the drift boxes and detectors both in the SLD and in separate test stands have been performed. Tests in SLD with the fiber-optic calibration system include the demonstration and measurement of electron drift paths, checks of the anode wire calibration, and the performance of the fiber-optic system in general. Other tests include measurements of the uniformity of TMAE concentration in a drift box and measurements of single electron diffusion and photon feedback in three drift gases. >

The energy resolutions of 976 keV conversion electrons from a /sup 207/Bi source are measured in a gridded ionization chamber filled with tetramethylsilane (TMS) and tetramethylgermanium (TMG), and are found to be about 5.71, 5.53% (RMS) for TMS and TMG, respectively. We discuss on the difference between the obtained energy resolution and the theorically limited energy resolution. We also deduce a simple method of estimating the electron lifetime by a gridded ionization chamber. The electron lifetime, free ion yield and thermalization length for these liquids are measured by this simple method.

We report on a study of correlation between readout pulses and lights of streamer produced in the glass resistive plate chamber (RPC) with six Ar gas mixtures (Ar/butane-silver/HFC134a). The streamer pulse produced by cosmic-ray are analyzed as a function of Ar/HFC134a mixing ratio using a digital oscilloscope. The streamer image due to the lights from the streamer is taken by using an image intensifier and a CCD camera. The average streamer size become larger linearly with increase Ar gas mixing ratio. The Ar/HFC134a ratio dependence of the charge and intensity were studied. The analysis of the light image of streamer might be useful for us to design the pickup pad width for the readout.

The Resistive Plate Counters (RPC) has been provided for K/sub L//sup 0/ and muon detection in the BELLE experiment at KEK. The glass RPCs have been extensively tested using single cosmic-ray muons. We report on the performance of the endcap RPC with emphasis on detection efficiency and multiple hits of readout strips.