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High Voltage. Requirements Commercial Solutions Custom Solutions. Requirements. 2076 LST tubes 4152 High Voltage Channels Up to 5 kV Regulated to 1% Current monitoring nA resolution Over-current protection Fine granularity (individual tubes). Voltage and Current.
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High Voltage Requirements Commercial Solutions Custom Solutions K. Honscheid, Ohio State University
Requirements • 2076 LST tubes • 4152 High Voltage Channels • Up to 5 kV • Regulated to 1% • Current monitoring • nA resolution • Over-current protection • Fine granularity (individual tubes) K. Honscheid, Ohio State University
Voltage and Current • Wide HV plateau(depending on gas mixture, chamber construction etc) fixed HV for all tubes • Operating point depends on gas mixture (variations), pressure, temperature, tube-tube variation. • Tube “conditioning” adjustable but tubes can still be grouped together with a common HV value • Current Estimates • for a typical 0.2 Hz/cm2 expect 60nA per tube • for a worst case rate of 2 Hz/cm2 expect 640 nA K. Honscheid, Ohio State University
Commercial Solutions • CAEN 527 or similar • Too expensive • CAEN 546 • 4u crate, slots for 8 modules for a total of 96 ch • One HV setting per module • Individual channel current monitor • CAENET VME interface to slow control • Available from CAEN by special order • Cost estimated to ~$160k for 1000 channels • Used by LVD experiment (Gran Sasso) • 3000 channels might be available K. Honscheid, Ohio State University
Over-current protection (ZEUS) 6 kV Limited streamer tube LST Voltage Voltage Current K. Honscheid, Ohio State University
Custom Solution or 4000+ HV channels for less than $200k • OSU electronics engineers (Rush, Smith) designed a system similar to the CAEN 546 solution. • single HV • individual current monitor • integrated protection • “pizza box” design • up to 50 ch in 1u • stand-alone (no crate or crate controller required) • Details at www-physics.mps.ohio-state.edu/~klaus/LST/HV/HV.htm K. Honscheid, Ohio State University
Block Diagram K. Honscheid, Ohio State University
Schematics (HV Regulator, Controller) K. Honscheid, Ohio State University
Schematics II (HV Distribution Channel) K. Honscheid, Ohio State University
First Prototype (5 ch) 15 V In Floating 5V Supply HV Op-Amp Current Monitor Outputs Current Monitor Protection 0-5 kV Out 6kV Dc/Dc K. Honscheid, Ohio State University
Status, Summary and the Next Steps • Commercial Solution • HV crate available at Padova, soon at OSU • Test CAEN 546 system from LVD • Integrate protection circuit (if necessary) • Custom Solution • Status • Test and prototype tested and fully operational • Based on preliminary cost estimate 4000+ channels can be build with our budget • Next Steps • Complete digital part, integrate micro controller • Test stability and reliability • Can be ready in time for module production and QA test stands • Need to decide if (and how far) OSU solution should be pursued …but it is hard to beat a “free” system • Start system engineering (connectors, distribution…) K. Honscheid, Ohio State University