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The Babar IFR Low Voltage System

The Babar IFR Low Voltage System. Naples, 12/15/1997 Electronic review. Requirements. The FEC’s for the IFR include @ 3200 boards to do discrimination, pulse shaping and address encoding.

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The Babar IFR Low Voltage System

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  1. The Babar IFR Low Voltage System Naples, 12/15/1997 Electronic review

  2. Requirements • The FEC’s for the IFR include @ 3200 boards to do discrimination, pulse shaping and address encoding. • The FEC’s are located as close as possible to the pickup electrodes not to spoil with long cables the good time resolution of the RPC’s • FEC’s come in two flavors, as induction electrodes are on both sides of the RPC’s. • Power consumption is different by @ 20% : positive input FEC’s use more power than negative. • Two voltages are needed : +7 and -5.2 V • Typical consumption are: +.31/-.12 neg.. Fec’s +.37/-.16 pos. Fec’s • Total power drawn: @ 8KW (+7) , 2.5 KW(-5.2) • Corresponding currents : 1100 A (+7) , 450 A (-5.2)

  3. Design Philosophy • Given the amount of current to be supplied, locate power modules relatively close to utilization. • Use a relatively high number of power modules so that (unlikely) failures would bring down a limited part of the IFR. • Select a very reliable product (MTBF >40,000 h) • Use a connection scheme in which each board is independently attached to L.V.: most of the barrel boards in fact cannot be reached without opening BaBar …. and this is not even enough.

  4. Power supply selection • The devices we have selected are produced (almost custom) by Power Control System: • Models chosen come in two types: 400W or 100W (output power). • The MTBF quoted by the manufacturer is 80,000 h and 100,000 h respectively. • At full power e = 75% (see Tech data sheet) • Other features include • Forced ventilation for the 400 W model • 95 oC shut-off • TTL/CMOS ramp down/up capability • Primary current limit @ 30 A for the 400 W model • Line regulation better than 1% • Load regulation better than 1% . • Calibrated shunts to measure output currents.

  5. S-100-P Data Sheet

  6. S400-7 data sheet

  7. Power clusters • The maximum number of boards to feed is : • 1536 barrel • 864 backward end cap • 924 forward end cap • The spatial distribution of the boards forces the use of power cluster for each subsystem. • We have planned 2 power clusters for the barrel on each (East and West) platform, and one power cluster on each half endcap. • The barrel power clusters consist of two 6U crates (Barrel Supply Power Modules)which contain 3 7V/400W modules and one -5.2V/400W module. • The end-caps power clusters consist of ; 1 6U crate containing two 7V/400W modules and three -5.2V/100 W modules (HPSM) and 1 3U crate containing 1 7V/400W module and 1 -5.2/100W module. • The total power capability installed is 9.6 KW @+7V and 3.2 KW @-5.2. The power margin is about 20%. • Power dissipation of the cluster: 800 W barrel 400W end-caps.

  8. The 6U barrel crate

  9. The End-cap 6U crate

  10. Boards power distribution • It is highly desirable to have individual (dis)connect of the boards, even if each of them is fused on the two voltages ( and crow-bared on the +7). • Very reliable connection needed (@ 10,000 connections to do) ß • Use faston connections for individual boards inside iron gaps. • Boards from the last three layers in the barrel and vertical strips in the end-caps are located in small crates on the outside of BaBar. • Power cables for the iron gap FEC’s go through the conduits used to extract signals, in separate compartments. Plenum rated cables (Belden parts # 83503) are used. • 12 conduits on each end (+z and -z) carry the cables to the outside world in the barrel and three conduits are used for each half end-cap.

  11. Boards power distribution (cont.) In the barrel each conduit has a fan-in/fan-out device sitting on top of the f wire-ways 24 (12 on each end) of those distribution points have to be equipped. One distribution point power 48 iron gap Fec’s (layer 1-16) and one minicrate (layers 17,18 19). One sextant is serviced by 2 distribution points connected to DIFFERENT power modules. In the end-caps, each half door has three distribution points for the iron gap FEC’s. (Each of these has to feed 72 negative FEC’s). All the positive FEC’s in the end-caps are in minicrates , so individual connection for series of those are foreseen. Distribution points were designed so that a max. current between 20 and 25 A would be split in them: this figure sets the gage for the interconnecting wires.

  12. The single barrel conduit distribution box

  13. The power distribution on one end of the barrel (conceptual)

  14. The power distribution on one half the back end-cap (conceptual)

  15. The power distribution on one half the forw.end-cap (conceptual)

  16. Components inventory and purchasing

  17. Fast tour of components • 3 conductor cable Plenum Belden parts # 83053 • Faston and faston blocks AMP parts # • Metal containers for faston blocks • Connection wires to the power modules: • AWG 2 10 m. power supply distrib. Box • AWG 10 5 m. distr. Box barrel minicrates • AWG 2 5 m. power supply end-caps minicrates • Power supply modules • Crates 6U and 3U eurocrate standard with slides • Monitoring cables • buffer amplifiers to match GMB’s input range • Fan unities 12 (one per crate) • Solid state relay to remotely turn on crates • Din Rail power supplies switches and cables (12) • Interface for software turn-on.

  18. Installation schedule • Power supply modules: • 80% purchased; 70% at SLAC • Cables: • FEC’s connection purchased ; harness in production at Naples. • Supplies-distributors on hand (SLAC store) • Contact blocks: • purchased, being delivered at SLAC (Anderson) • Faston • purchased being delivered at SLAC (Anderson) • Crates • Purchased being delivered at Frascati • Some work to do on the to punch holes slots etc. ready by the 10th of January. • Prototype crate (BPSM) • ready with all the cabling /monitoring before Christmas. Few BPSM ready at SLAC by end of January.

  19. Conclusions • The low voltage system for the FEC’s is essentially designed; prototype is finished and production is ready to go. • In spite of the standard type of requirements, practical design has presented few challenges mainly due to the sizable amount of power one has to produce and distribute. • Solutions have been chosen to maximize reliability and ruggedness of the plant. • With our design we’ll be able to handle single boards connections from the outside of the detector . • Reliability of the active parts are well above the limit we could have tested with the RPC quality controls runs during production.

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