M. Zito

Large bulk-micromegas detectors for TPC applications in HEP

Bulk-MicroMegas detectors are based on a novel technology which is of particular interest for large area Micro Pattern Gas Detectors (MPGD). Their manufacturing process combines detector construction simplicity and robustness, allowing large sensitive areas to be produced at low cost. Such devices provide very good gas gain uniformity and detection coverage with small dead spaces. They are ideally suited in HEP applications where large volume tracking detectors with low material budget are required. This is the case, for instance, of the T2K neutrino experiment in Japan, in which large Time Proportional Chamber (TPC) devices will be used. Bulk- MicroMegas detectors are also being considered for the future Linear Collider Detector. We present in this paper the recent developments and performance of bulk-MicroMegas detectors for the T2K TPC.

AFTER, the front end ASIC of the T2K Time Projection Chambers

The T2K (Tokai-to-Kamioka) experiment is a long baseline neutrino oscillation experiment in Japan. A near detector, located at 280m of the production target, is used to characterize the beam. One of its key elements is a tracker, made of three Time Projection Chambers (TPC) read by Micromegas endplates. A new readout system has been developed to collect, amplify, condition and acquire the data produced by the 124,000 detector channels of these detectors. The front-end element of this system is a a new 72-channel application specific integrated circuit. Each channel includes a low noise charge preamplifier, a pole zero compensation stage, a second order Sallen-Key low pass filter and a 511-cell Switched Capacitor Array. This electronics offers a large flexibility in sampling frequency, shaping time, gain, while taking advantage of the low physics events rate of 0.3 Hz. We detail the design and the performance of this ASIC and report on the deployment of the frond-end electronics on-site.

The T2K neutrino oscillation experiment

T2K is a long baseline (295 km) neutrino oscillation experiment planned to start taking data in 2009. A powerful proton beam in the JPARC Laboratory (Tokai, Japan) will produce a neutrino beam aimed at Super-Kamiokande. The goal of T2K is to probe Vμ → Ve oscillations with a sensitivity an order of magnitude better than current experiments and eventually to measure θ13, the last unknown angle in the PMNS neutrino mixing matrix.

A Measurement of the Neutral B Meson Lifetime using Partially Reconstructed B0 --> D*-pi+ Decays

The neutral B meson lifetime has been measured with the data collected by the BABAR detector at the PEP-II storage ring during the year 2000 for a total integrated luminosity of 20.3 fb{sup -1}. The B{sup 0} {yields} D*{sup -} {pi}{sup +} decays have been selected with a partial reconstruction method in which only the fast pion from the B{sup 0} decay and the slow pion from D*{sup -} {yields} {bar D}{sup 0}{pi}{sup -} are reconstructed. The B{sup 0} lifetime has been measured to be 1.510 {+-} 0.040 {+-} 0.038 ps with a sample of 6971 {+-} 241 reconstructed signal events.