L. Villaseñor

This handbook was written for the Drift Chambers introductory laboratory course to be held at 11th Mexican School of Particles and Fields that will be held at the Universidad Veracruzana on the campus of the University at Xalapa, Veracruz, Mexico. This course intends to introduce drift chambers, which play an important role in particle physics experiments as tracking detectors. We start such laboratory course with a brief review of the physics theoretical background. The experimental setup consists of a single-sided, single-cell drift chamber, a plastic scintillator detector, the standard P-10 gas mixture (90% Ar, 10% CH4) and a collimated 90Sr source. The measurements on the drift velocity of electrons, its change as a function of a drift field, gas gain and diffusion are performed at this laboratory course.

Muons decaying in the water volume of a Cherenkov detector of the Pierre Auger Observatory provide a useful calibration point at low energy. Using the digitized waveform continuously recorded by the electronics of each tank, we have devised a simple method to extract the charge spectrum of the Michel electrons, whose typical signal is about 1/8 of a crossing vertical muon. This procedure, moreover, allows continuous monitoring of the detector operation and of its water level. We have checked the procedure with high statistics on a test tank at the Observatory base and applied with success on the whole array.