Dale A. Ouimette

A straw tracking system to study rare KL decays

Abstract Construction, readout, tests, and performance of planar drift chambers, based on 5-mm diameter copperized Mylar straws, used in experiment E871 at BNL is briefly described and discussed.

New experimental limits on KL0--> microe and KL0-->ee branching ratios.

A search for the decays {ital K}{sub {ital L}}{sup 0}{r arrow}{mu}e and {ital K}{sub {ital L}}{sup 0}{r arrow}ee has produced no examples of either process. When normalized to the decay {ital K}{sub {ital L}}{sup 0}{r arrow}{pi}{sup +}{pi}{sup {minus}}, the 90%-C.L. upper limits on the branching ratios are {ital B}({ital K}{sub {ital L}}{sup 0}{r arrow}{mu}e){lt}2.2{times}10{sup {minus}10} and {ital B}({ital K}{sub {ital L}}{sup 0}{r arrow}ee){lt}3.2{times}10{sup {minus}10}.

Fast parallel pipelined readout architecture for a completely flash digitizing system with multilevel trigger

Abstract We have built, and used to take physics data, a digitizing and readout system for Brookhaven AGS Experiment 791, a high-rate search for rare kaon decays. All digitization of charge and time information is “flash” (performed in less than 200 ns), followed by front-end buffering and a pipelined readout with massive parallelism. A data transfer rate of 0.4 Gbyte/s into dual-port memories in eight 3081-emulating processors has been achieved. A readout-supervising circuit coordinates the three levels of event triggering and the movement of data throughout the system. The host Micro-VAX is interrupted only for the uploading of packets of fully filtered events from the 3081/Es. Digitizing and data transfer from the front end to the 3081/Es contribute negligible deadtime to the experiment.

A Versatile Secondary Trigger for a Multi-Detector System

The electronics of a secondary trigger for particle physics is described. The system has several desirable features that solve track recognition problems in situations where several subsystems of various cell configurations participate in the decision making. Track curvature and multiplicity are the criteria used. Versatility is attained through the use of Programmable Array Logic (PAL) and a 48-bit wide ROM-based sequencer that determines, with the resolution of a cell, the participation of each element in the decision process. Data from layers with arbitrary numbers of cells are shifted in a programmable manner through a PROM mask containing eight different track definitions. The results of any one of the eight triggering criteria are available 5.6 ¿s after the end of drift interval.

A Multi-Hit Drift Time Digitizer

We describe electronics for a drift chamber which measures drift times and has multi-hit capability. The system is based on a stable (± 0.005%) 125 MHz clock which eliminates the need for frequent calibrations. The times are digitized according to a Gray code in order to restrict transition errors to the least significant bit. The least count is 4 ns which contributes an rms error of 58 ¿m to the measurement of drift distance.

A straw drift chamber spectrometer for studies of rare kaon decays

We describe the design, construction, readout, tests, and performance of planar drift chambers, based on 5-mm-diameter copperized Mylar and Kapton straws, used in an experimental search for rare kaon decays. The experiment took place in the high-intensity neutral beam at the Alternating Gradient Synchrotron of Brookhaven National Laboratory, using a neutral beam stop, two analyzing dipoles, and redundant particle identification to remove backgrounds.

New experimental limits onKL0→μe andKL0→ee branching ratios

A search for the decays {ital K}{sub {ital L}}{sup 0}{r arrow}{mu}e and {ital K}{sub {ital L}}{sup 0}{r arrow}ee has produced no examples of either process. When normalized to the decay {ital K}{sub {ital L}}{sup 0}{r arrow}{pi}{sup +}{pi}{sup {minus}}, the 90%-C.L. upper limits on the branching ratios are {ital B}({ital K}{sub {ital L}}{sup 0}{r arrow}{mu}e){lt}2.2{times}10{sup {minus}10} and {ital B}({ital K}{sub {ital L}}{sup 0}{r arrow}ee){lt}3.2{times}10{sup {minus}10}.

New Experimental Limits on

A search for the decays {ital K}{sub {ital L}}{sup 0}{r arrow}{mu}e and {ital K}{sub {ital L}}{sup 0}{r arrow}ee has produced no examples of either process. When normalized to the decay {ital K}{sub {ital L}}{sup 0}{r arrow}{pi}{sup +}{pi}{sup {minus}}, the 90%-C.L. upper limits on the branching ratios are {ital B}({ital K}{sub {ital L}}{sup 0}{r arrow}{mu}e){lt}2.2{times}10{sup {minus}10} and {ital B}({ital K}{sub {ital L}}{sup 0}{r arrow}ee){lt}3.2{times}10{sup {minus}10}.

K^0_L \to \mu e

The circuit generates a fast (≈200 ns) trigger in response to two particles (one π and one μ) passing through two scintillation hodoscopes and satisfying criteria of direction and spatial separation. The selection of 4-fold coincidences identifying the relevant tracks is effected by simultaneous RAMs1 in coincidence with SSI logic.