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A device for fabricating thin-wall (straw) drift tubes using polyethylene terephthalate film 36 μm thick by ultrasonic welding is described together with the technique for controlling their quality. The joint width amounts to 0.4–1.0 mm. The joint breaking strength is 31.9 kg/mm2. The argon leakage from a tube of volume 188.6 cm3 under a pressure gradient of 1.0 atm does not exceed 0.3 × 10–3 cm3/min, which is mainly related to the absence of metallization in the joint vicinity. The high strength, the low tensile creep due to the absence of glued layers, the small value of gas leakage makes the new tubes capable of reliable and long-term operation in vacuum, which is confirmed by the operation of 7168 straw tubes for two years in the NA62 experiment.

The NA62 low mass spectrometer consists of 7000 straw tubes operating in vacuum. The front-end electronics is directly mounted on the detector and connected by a flexible PCB. The front-end board provides the amplification, shaping, discrimination and time measurements of the analogue signals from 16 channels. After digitisation the data is sent to a VME 9U read-out board. The data, once matched with the trigger, is sent to the next step and used by the trigger level 1 algorithm. The front-end and read-out systems of the detector will be presented along with the first results of the detector performances.

The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (√sNN = 2-4.9 GeV) is to discover fundamental properties of QCD matter, namely, the equation-of-state at high density as it is expected to occur in the core of neutron stars, effects of chiral symmetry, and the phase structure at large baryon-chemical potentials (μB ≥ 500 MeV).We are focusing here on the contribution of JINR to the CBM experiment: design of the superconducting dipole magnet; manufacture of the straw and micro-strip silicon detectors, participation in the data taking and analysis algorithms and physics program.

Developing silicon strip sensors for the CMS Preshower detector we have noticed that some strips have a noise higher than the average and not correlated to a high leakage current. In order to investigate this effect we have developed a setup for noise measurement on wafers and diced sensors that does not require bonding. The set-up is based on the DeltaStream chip coupled to a probe card. We have tested 45 sensors and found that the strips with an above average noise have a higher relative current increase as a function of voltage, DeltaI/(IDeltaV). We also observed that, on these strips, the breakdown occurs within about 60 V from the voltage at which the noise is observed. We describe our measurement method and present the results. (C) 2002 Elsevier Science B.V. All rights reserved. Nuclear Instruments & Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment