FP420 Low and high voltage supply Henning E. Larsen, INFN Dec rev.2

Revision information Since I made the slides, the frontend has gone from 6 to 4 detectors/superlayer. I have as far as possible tried to take this fact into account in this revised version.

HV-LV supply segmentation Damage depends on distance from the beam. Required bias voltage and current increase with radiation dose. Drawing: From Ray Thompson PT1000 Temperature sensor? Pixels:50x400um and 400x50um MCC: Module Controller Chip 1 Superlayer = 2 Hybrids/Blades 4 2D detectors 1 MCC 1 Read-out interface Now only 2 det.

Specification for LV for 1 superlayer PixChips/4VoltageCurrentCurrent limit Analog V Nom 2V 5-70mA100mA Digital V Nom 2V 1% occupancy: 40-50mA 10% occupancy: 60-70mA 100mA MCC/1VoltageCurrentCurrent limit Digital V120mA-150mA170mA Ripple at 1MHz is critical. Remote on/off. Monitor current. Digital supply for Pixelchip and MCC is common as seen from supply. 4 PixChips + 1 MCC + Read-out? VoltageCurrentCurrent limit Analog V20-280mA310mA Digital V1% occ 280mA-350mA 10% occ 360mA-430mA 480mA Monitor resolution<20mV<10mA DEC 2006:Notice change from 6 to 4 detectors per superlayer

Specification for HV supply 4 detectors 2 voltages VoltageCurrentCurrent limit V 0-120V(*) <1mA1mA Monitor Resolution <1V1μA Voltage is negative, but floating. Referenced to AVDD on PIXELCHIP, not GND HV connection diagram used in Atlas Source: Maurice Garcia-Sciveres DEC 2006: Notice change from 6 to 4 detectors per superlayer (*) -120V is also sufficient.

One of 4 stations Counting inventory: Super layers: 2 experiments * 2 zones * 5 pockets * 5 superlayers=100 super layers LV supplies: 100 super layers * 2 voltages = 200 channels HV supplies: 100 super layers *2 voltages = 200 channels Crate count is preliminary

Overall system geography

Commercial: Wiener solution A 2x4 Mpod-like systems (8U,19” each) will be arranged to provide the requested voltages over 500 m distance, Located in the counting rooms and will host both HV and LV modules. 2 cable pipes with 10 cm section (or probably less) are needed. The Mpod will require custom -150V modules.. 4*2 Mpods with 80ch each. Location: Counting room Mpod x 8 150k€ for Mpod’s 100k€ for cables Now only 2 HV

Commercial: Wiener solution B 2x10 Maraton-like radiation tolerant systems (3U) will provide LV and operate close to the detectors. 2x2 Mpod-like devices will supply HV from the counting rooms. This solution requires a customization of Maraton in order to optimize it for low currents. The Mpod will require custom -150V modules. Cost not yet discussed. One per pocket Mpod x 2 x 5 One per pocket One per crystat 1 Maraton Now only 2 HV

Commercial: Wiener solution C 2x22 Maraton-like system will provide HV and LV and operate close to the detectors. Simple cable These systems will be optimized for the given current range. Need customization for -150V modules Proven radition tolerance: 722Gy, n/cm 2 Cost not yet discussed 1 Maraton 2.2 crates per pocket H=3U=131mm 1 Maraton 2.2 crates per pocket x 11 Now only 2 HV

CMS/Atlas counting room Commercial: Caen SY1527 A1676A Crate Ctl A1676A Crate Ctl A3486 2x48V Power A3486 2x48V Power Atlas or CMS Slow control EASY 3000 A ch LV A ch LV A ch LV A ch LV A ch LV EASY 3000 A ch HV A ch HV A ch HV A ch HV A ch HV A ch HV A ch HV FP420 pocket FP420 pocket FP420 pocket FP420 pocket FP420 pocket LHC Tunnel EASY 3000 A ch LV A ch LV A ch LV A ch LV A ch LV EASY 3000 A ch HV A ch HV A ch HV A ch HV A ch HV A ch HV A ch HV FP420 pocket FP420 pocket FP420 pocket FP420 pocket FP420 pocket Cryostat 1Cryostat 2

Commercial: Caen, pictures SY1527 EASY 3000 Not to scale A3009 A3501

Commercial: Caen A3009 LV A3501 HV A3009 LV A3501 HV A V Power Modules 220k€ Cable ~20k€ Delivery not possible before summer 2008 due to LHC production bottle neck. Only few samples by mid CAN bus link has to be extended to 500m. This is not yet tested High voltage only up to 120V Cable: 500m

Commercial: Eplax GmbH Entirely custom design based on their >20year experience with standard power supplies and our specification No experience with radiation tolerant supplies. Non recurring engineering cost: 25k€ Supply for 1 superlayer: 900€ Total cost: 115k€ (excl cables)

LV supply: simulation model with long lines Current transients are mainly limited by capacity at the load. Simulation shows a 500m+500m cable with 20% current change for C=1µ, 5µ, 50µF Conclusion: 500m++ of LV cables is not feasible

Simulation, Low voltage, 500m cable

LV supply using LHC4913 If we make our own custom solution a regulator like LHC4913 is very convenient and unique. It is now being ported to a military/space qualification => higher cost, but presumably available. 1.Rad hard. 2.Extensively used at LHC detectors. 3.Remote sense on the positive and negative supply. This means it can compensate for resistive cable voltage drop. This means that with LHC4913, a thinner cable can be used. 4.Adjustable current limit. 5.ON/off switch input.

ADC’s: DCUF Detector Control Unit (CMS) CMS central tracker for the monitoring of some embedded parameters like supply voltage and currents on the front-end read-out modules Is available in the quantity we need

HV principle diagram + V bias - Cable V in αI bias αV bias I bias Transformer +rectifier R3R3 R2R2 R1R1 R1R1 R2R2 Pass transistor DAC Simple linear regulator to make radiation tolerance easier to implement with COTS Monitor, remote control, galvanic isaolated Galvanic isolation ADC’s

“Home made” in-tunnel-solution cost estimate Modules 120k€ Cable 20k€

Location for service electronics Until today we thought: If the LV electronics should stay within some 20m from the detectors, there are only two possible locations (ref Daniela Macina): –Below the new cryostat, where the radiation level is estimated at about 700 Gy per year of running at full luminosity; –Below or near the adjacent magnets, where the radiation is much lower and estimated at about 15 Gy per year, but where there are already other things. Space for service electronics. Few meters of cable Radiation level? Shielding possibility? Space for electronics needing close proximity to detectors At mechanics meeting 29/9/06 we saw: FP420 detectors

Issues to finalize Location of support electronics in tunnel. Favour of putting it under the adjacent magnets. Cable length about 10m. Radiation level to expect. There ought to be simulations done with shielded cryostat at fp420 to evaluate the dose. Current assumption is 15GY/y Home made or commercial solution? Cable distances from fp420 to the counting room for all 4 stations have to be estimated more precisely than the current 500m Specification of number of channels Specification of LV supply for superlayer readout part (Opto board). Need for temperature monitor of FE for the cooling system. Where should it be serviced? If in the HV-LV unit, we need define a local interface with cooling as this cant go through slow control. Are there any requirement for: –Hardware interlocks related to temperature? –Graceful power down =UPS backup?

Conclusions Some interesting solutions from industry. Some almost off the shelf. We have an outline of how to build the LV-HV our selves but chip supply is critical. We need to make up our minds if we buy or build ourselves. We are opting for putting the LV/HV crates under the adjacent magnets