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A fine-grain hodoscope to measure the position of showers in the outer (>52 cm) region of the E-705 electromagnetic calorimeter is described. The hodoscope is constructed with two layers of vertical conducting plastic tubes for the X position measurement of showers. Y position measurement of showers was accomplished by cathode-induced horizontal strips. A 50/50-ethane mixture bubbled through isopropyl alcohol at 0 degrees C was circulated through the tubes in parallel. The tubes were operated at +1.925 kV on the wire (below the region of saturated avalanche) in the limited proportionality mode. The hodoscope is described, and results are presented for the position resolution, shower width, and charge detected as a function of calibration electron energy. >

The design and performance of a 4.2-radiation-length, lead-sandwich, gas tube hodoscope are discussed. The device, measuring 1*2 m/sup 2/ in area and 12 cm in depth, was used in Fermi National Accelerator Laboratory experiment 705. Multiple samplings of anode wires situated within three-walled aluminum tubes were used to generate an X coordinate; similarly, capacitively coupled copper-clad strips were ganged together to yield a Y coordinate. The results reviewed of an analysis of electron calibration data taken during a recent six-month running period are reviewed. The position resolution (in millimeters) is seen to be 0.8+3.3/ square root E+31/E for the 9.92 mm-spaced wires and 0.6+3.2/ square root E+32 for the 12.5-mm strips, where E represents the electron beam energy in GeV. The correlation between energy as measured by the wires and energy as measured by the strips is fairly tight, with an asymmetry RMS (root mean square) for 30-GeV electrons of about 4%. >

Three multiwire proportional chambers (MWPCs) with high-rate capability have been constructed for Fermi National Accelerator Laboratory experiment 705 (charmonium and direct photon production by pi /sup +or-/,p and p at 300 GeV/c). Each chamber, with a sensitive area of 308 cm/sup 2/, consists of three anode planes, wound with 12.5- mu m-diameter gold-plated tungsten/rhenium wire, facing 25- mu m graphite-coated kapton cathode planes at a distance of 3 mm. Wire spacing is 0.75 mm in two of the MWPCs and 1.00 mm in the third one. After a few weeks of running on 'magic gas' with a beam flux of up to approximately 10/sup 7/ particles/cm/sup 2/ s, severe damage occurred to the graphite coating. All cathode planes were replaced by aluminized kapton, and the chambers worked successfully for the next three months until the end of the run, when a 10% efficiency drop was observed after a total accumulated charge of approximately 1 C/cm of sense wire. After the end of the run the chambers were disassembled and inspected. A white deposit with a characteristic wire pattern etched away from the Al coating was observed in the region of the beam spot. >

A trigger processor for the selection of events in which photons of large transverse momentum are detected by a lead and scintillating glass calorimeter was designed, constructed, and operated at interaction rates ranging from 2 kHz to 2 MHz. The system achieved suppressions of the raw interaction rate of as much as 1*10/sup -5/. Raw distributions of transverse momenta and direct photon event sensitivities are presented for data taken with 300-GeV/c pion and proton beams on a lithium target. >

The E705 scintillation glass/lead glass electromagnetic calorimeter is described. The trigger used for recording high transverse momentum direct photon signals from 300 GeV/c π−, π+, \(\bar{p} \), p interactions in a Li7 target is explained. Preliminary results on the response of this direct photon trigger and electromagnetic calorimeter and expected event sensitivities are presented.