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Slac-~1~~9165 (expi) Design of a Data Acquisition System for Lass* December 1972
| Content Provider | Semantic Scholar |
|---|---|
| Author | Friday, R. G. Shapiro, Sidney Williams, Stephen H. |
| Abstract | Introduction The large aperture solenoid spectrometer (LASS, Fig. 1) now under construction at SLAC will put a strain on already existing data acquisition equipment to handle the. projected 100 kiloword per second data rate, In order to meet this higher data rate and also provide a flexible data system to handle multiple users a new data acquisition system is being designed. LASS is formed of two large magnets (Fig. 2). The first is a superconducting solenoid having a field region approximately 12 ft long with B=25 kG in the beam direction. The incident beam passes through a 1 meter hydrogen target at the upstream end of this solenoid. The secondary particles resulting from an interaction are trapped in helical orbits in the solenoid and their momenta measured by measuring the curvature of these helices. As high energy secondaries with small production angles have little curvature and cannot be measured well in the solenoid,a conventional dipole follows the solenoid to allow measurement of their momenta. Thus a varied array of detectors within the solenoid, and fore and aft of the dipole, is required to reconstruct the particle trajectories of an event. To measure wide angle tracks the target is surrounded by concentric cylinders of proportional chambers and spark chambers using capacitor-diode (C-D) readout.. These are under design and production by our Cal-Tech collaborators. Downstream of the target, at 75 cm intervals along the solenoid axis, are modular detectors, each composed of 2 gaps of 61x6' spark chamber with capacitor diode (C-D) readout, plus 3 gaps of proportional chamber, 1'~ 1' centered on the beam axis, where particle density is highest. Proportional chambers are used to distinguish desired tracks from out-of-time background because their time resolution is 0.1 psec, compared to the 0.5 psec resolution of the spark chambers. It is not possible to use proportional chambers throughout because their complex readout costs about $7/w&e (one wire per mm of chamber periphery) so the bulk of the solenoid is covered by C-D spark chambers which costs about ?l/wire. Magnetostrictive (M-S) readout would be less expensive yet, but C-D readout must be used because of the high magnetic field in the sol'enoid region. Between the solenoid and dipole there are 3 more proportional chamber-spark chamber modules of the same design as the solenoid detectors. The spark chambers may have magnetostrictive readout if it is found possible to shield the M-S wire adequately, but … |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.slac.stanford.edu/pubs/slacpubs/1000/slac-pub-1165.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
