Pad Repeater

Expert information is presented here.

The repeater is a block of electronics located next to the detectors with the original goal to keep the capacitive load of the frontend amplifiers reasonably low (short line length to the receiver). As for the BST Pad Detector it serves additional tasks:

1. regulate three main and several supplemental supply/bias voltages for the hybrid;
   
2. synchronize trigger data to the H1 clock;
3. do a digital 4:1 frontend data reduction;
4. provide testpulses to the detectors if advised;
5. provide slow-control adjustable thresholds for the preamplifier/discriminator chip;
6. allow for individual switching of the bias voltages of the connected detectors;
7. measure individual bias currents;
8. measure temperatures by means of sensors distributed inside the BST and repeater volume.

The repeater implies a water cooled power regulator section (1), a signal processing section with receivers, field configurable logic (XILINX) and cable drivers (2...4) and a CAN bus based slow control system with D/A-converter (5), register (6) and A/D-converters (7, 8). This functionality is for 8 detectors collected on one printed circuit board; eight of these boards will be mounted together with eight strip detector repeaters in a common repeater frame which is plugged close to the BST inside the silicon detectors' mounting tube. (For the BST 1996 version only four boards are installed. In 1997 an additional board of a revised version has been added which is the only one to stay there in 1998.)
Adjacent repeaters are coupled to each other by a 12pin bridge cable which carries some serial control signals and a 4-bit logic link between the physical sectors of the detector.

The Pad Repeater is powered through a 50pin cable from the PDS module in the trailer. Repeater and hybrid electronic circuitry dissipate 20 Watts approx. (BST 1996 setup: 30 Watts).

To be completed by a picture.

Back to the Shift Instructions. To the BST site.