THIS DETECTOR CAN'T BE BUILT (WITHOUT LOTS OF WORK)
Most of us believe that e{sup +}e{sup -} detectors are technically trivial compared to those for hadron colliders and that detectors for linear colliders are extraordinarily trivial. The cross sections are tiny; there are approximately no radiation issues (compared to real machines!) and for linear colliders, the situation is even simpler. The crossing rate is miniscule, so that hardware triggers are not needed, the DAQ is very simple, and the data processing requirements are quite modest. The challenges arise from the emphasis on precision measurements within reasonable cost constraints. The Silicon Detector, SD, is a ''preconceptual'' design of a high performance detector for the NLC, with reasonably uncompromised performance in general and stressing superb energy flow performance with its electromagnetic calorimeter (ECal). However, it is assumed from the beginning that funding will be very tight and that the detector costs must be constrained and rational. It also remains to be demonstrated by detailed simulation that many aspects of this performance are required by the physics. A quadrant view of SD is shown in Figure 1. Working radially out, the detector begins with a 5 layer CCD vertex detector (VXD) with an inner radius of 1 cm. Tracking is provided by an array of 5 layers of silicon strip detectors arranged in barrels and planar endcaps. The tracker extends to 1.25 m, and is followed by an ECal consisting of alternating layers of tungsten and silicon diode detectors, totaling about 21 X{sub 0} in about 30 layers. The silicon diodes are segmented into pixels about 1 cm across, and are read out independently, producing a ''tracking'' calorimeter. The ECal is followed by the hadronic calorimeter (HCal), consisting of alternating layers of radiator (probably copper or stainless) and inexpensive track counting detectors, perhaps a suitably reliable version of resistive plate chambers (R{sup 2}PC's). Outside the HCal is a 5 T solenoid. The perhaps unusually large field is chosen to sweep e{sup +}e{sup -} pairs away from the VXD, to achieve excellent tracking performance in the somewhat modest 1.25 m tracking radius, and to separate charged and neutral particles in jets for energy flow performance in the ECal. Outside the solenoid is a series of iron laminations interleaved with R{sup 2}PC's that track muons, with the iron serving additionally as the flux return.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (US)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 801992
- Report Number(s):
- SLAC-PUB-9480; TRN: US0205627
- Resource Relation:
- Other Information: PBD: 30 Aug 2002
- Country of Publication:
- United States
- Language:
- English
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