A FASTBUS-based software trigger for the Mark II detector at the SLC
A new software trigger scheme has been developed to augment and enhance the existing charged and neutral triggers by providing sensitivity to new event topologies and some level of control over accelerator-induced backgrounds. Historically, the Mark II existed with two primary trigger components: a charged track finder based upon the central and vertex drift chambers and the time-of-flight counters; and an electromagnetic trigger based upon the total energy deposited in each of ten calorimeter modules. The trigger component of the new system is based upon the Mark II electromagnetic calorimetry but with significantly increased granularity and the inherent flexibility of software. Trigger processing also benefits from the relatively long period of time (up to 8.3 ms) between SLC beam crossings. The production of long-lived neutral particles provides an example of an event topology which would not have triggered in the old system. By decaying beyond the first few drift chamber layers, such particles avoid the charged particle trigger, yet could produce clear signals in the calorimeters. Another example is the class of events containing a single photon as the visible particle such as occur in the reaction e{sup +}e{sup -} {yields} Z{sup 0}{gamma} {yields} {nu}{nu}{gamma}. Sensitivity to this reaction is necessary to measure the number of neutrino generations. One goal of the new trigger is to achieve nearly 100% efficiency for single photons of energy above 750 MeV. Such a trigger necessarily depends upon a very low and well understood accelerator background for success. A minimum ionizing particle trigger will provide good efficiency for Z{sup 0} {yields} {mu}{mu} or {tau}{tau} at the angles covered by the end cap calorimeters which increases the capabilities for measuring the forward-backward asymmetries. And finally, an improved trigger is more sensitive to complete surprises. 7 refs., 4 figs.
- Research Organization:
- Stanford Linear Accelerator Center, Menlo Park, CA (USA); Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 5799957
- Report Number(s):
- SLAC-PUB-4636; LBL-25299; CONF-8803123-1; ON: DE88012738
- Resource Relation:
- Conference: International conference on the impact of digital microelectronics and microprocessors on particle physics, Trieste (Italy), 28-30 Mar 1988
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SHOWER COUNTERS
TRIGGER CIRCUITS
COMPUTER ARCHITECTURE
DATA ACQUISITION SYSTEMS
FASTBUS SYSTEM
STANFORD LINEAR COLLIDER
ACCELERATOR FACILITIES
ACCELERATORS
ELECTRONIC CIRCUITS
LINEAR ACCELERATORS
MEASURING INSTRUMENTS
PULSE CIRCUITS
RADIATION DETECTORS
440104* - Radiation Instrumentation- High Energy Physics Instrumentation