H. Areti

A measurement of the response of an SCG1-C scintillation glass shower detector to 2–17.5 GeV positrons

We have measured the response of an electromagnetic shower counter constructed from the new scintillation glass (SCG1-C, Ohara Optical Glass, Inc.) to positrons in the energy range 2 to 17.5 GeV. We have measured the energy resolution of this 18.4 radiation length detector plus its attendant SF5 lead glass shower counter array to be ¿/E = (1.64 ± 0.14)% + (1.13 ± 0.33)%/¿E with the constant term dominated by variations in the conversion point of the positron and shower leakage. We found this counter to be linear over the energy range examined. We have also measured the light output of the SCG1-C counter relative to light output of the SF5 lead glass guard blocks using 17.5 GeV positrons. We find that the SCG1-C counter produces 5.10 ± 0.30 more light at the phototube than the SF5 lead glass counters.

High energy electromagnetic shower position measurement by a fine grained scintillation hodoscope

We have measured the centroids of high energy electromagnetic showers initiated by positrons in the energy range 2 to 17.5 GeV with a fine grained scintillation hodoscope composed of seven 1 cm wide elements placed behind a 3.6 radiation length (15 cm) converter composed of SCG1-C scintillation glass. A simple first moment calculation using the ionization observed in each element of this hodoscope yields a shower position resolution as a function of energy of: ¿(mm) ¿ 0.7 ± 5.6/¿E(GeV). We present results on the energy dependence of the shower profiles and the ionization measured by this hodoscope.

A fast processor for dilepton triggers

We describe a fast trigger processor, developed for and used in Fermilab experiment E-537, for selecting high-mass dimuon events produced by negative pions and anti-protons. The processor finds candidate tracks by matching hit information received from drift chambers and scintillation counters, and determines their momenta. Invariant masses are calculated for all possible pairs of tracks and an event is accepted if any invariant mass is greater than some preselectable minimum mass. The whole process, accomplished within 5 to 10 microseconds, achieves up to a ten-fold reduction in trigger rate.

A Measurement of the Response of an SCG1-C Scintillation Glass Shower Detector to 2-17.5 GeV Positrons

We have measured the response of an electromagnetic shower counter constructed from the new scintillation glass (SCG1-C, Ohara Optical Glass, Inc.) to positrons in the energy range 2 to 17.5 GeV. We have measured the energy resolution of this 18.4 radiation length detector plus its attendant SF5 lead glass shower counter array to be ?/E = (1.64 ± 0.14)% + (1.13 ± 0.33)%/?E with the constant term dominated by variations in the conversion point of the positron and shower leakage. We found this counter to be linear over the energy range examined. We have also measured the light output of the SCG1-C counter relative to light output of the SF5 lead glass guard blocks using 17.5 GeV positrons. We find that the SCG1-C counter produces 5.10 ± 0.30 more light at the phototube than the SF5 lead glass counters.

A large aperture spectrometer at Fermilab to study high mass dimuons

A large acceptance forward spectrometer located in a unique antiproton enriched beam has been used at Fermi National Accelerator Laboratory by Experiment 537 to study the production of high mass muon pairs. When the beam was operated at a momentum of 125 GeV/c, it had a flux of 1.5 × 107 particles per second of which 18% were antiprotons. The spectrometer was of closed geometry design and used drift chambers as the tracking elements. Operating over a relatively short period, the experiment accumulated the largest sample of antiproton-induced high mass dimuons of any experiment to date. The contamination of this data by pion-induced dimuons was less than 0.5%.

High Enery Electromagnetic Shower Position Measurement by a Fine Grained Scintillation Hodoscope

We have measured the centroids of high energy electromagnetic showers initiated by positrons in the energy range 2 to 17.5 GeV with a fine grained scintillation hodoscope composed of seven 1 cm wide elements placed behind a 3.6 radiation length (15 cm) converter composed of SCG1-C scintillation glass. A simple first moment calculation using the ionization observed in each element of this hodoscope yields a shower position resolution as a function of energy of: ?(mm) ? 0.7 ± 5.6/?E(GeV). We present results on the energy dependence of the shower profiles and the ionization measured by this hodoscope.