LIQUID IONIZATION CALORIMETRY WITH TIME-SAMPLED SIGNALS

We present the results of a study of amplitude and timing measurements made in a liquid krypton electromagnetic calorimeter, using multiply sampled signals of the shaped waveform. The measurements were designed to emulate the type of data that will be available from a calorimeter operating at future hadron-hadron colliders with short (approximately 20 ns) spacing between bunch crossings. Data have been collected with 18 ns sample spacing on waveforms from individual calorimeter section s with a shaping time of 40 ns and from 5 x 5 tower analog sums with a shaping time of 50 ns. The amplitude was measured using the analog su m signal, and the timing was measured using the signal from the indivi dual sections. The data were processed using the method of optimal fil tering, and a reduction in the noise of about a factor of two over tha t for a single sample is seen when using multiple samples for determin ing the amplitude. We find an energy resolution of 6.7%/square-root E, in agreement with the resolution measured for the same calorimeter us ing a single sample measured at the peak of the waveform. The timing r esolution for a section of a calorimeter tower with deposited energy e psilon can be expressed as square-root (c/epsilon)2 + sigma(cal)2, wit h a value of c of 0.38 GeV ns for the front section (the first 6 radia tion lengths) and 0.70 GeV ns for the back section, and a value of 0.1 5 ns for sigma(cal).