FP420 Low and High voltage supply Henning E. Larsen, INFN h.larsen@risoe.dk 29 Sep. 2006

Bias supply segmentation PT1000 Temperature sensor? HV: res +-1V, +-1uA Cinzia: 1/20nA to 1uA, Abs max is 1mA Voltage best up to 150V at least 100V This is a huge dynamic range! Will require 24 bit Damage depends on distance from the beam. Required bias voltage and current increase with radiation dose. Pixels:50x400um and 400x50um Drawing: Ray Thompson

Functions for a superlayer supply Superlayer consists of.. Detectors (Atlas pixel detctors), Front-end pixel-readout (Atlas Pixelchip), MCC, Optical transmitters PT1000 temperature sensor Each superlayer should be LV +HV supplied by a separate unit=> Electrical isolation Redundancy Modular servicable Isolation implies that it will have its… own ac-ac power transformer secondary winding and AC-DC rectifier bridge digital communcation interface isolated Linear regulators to have best radiation tolerance. Switch-mode regulators are much more compact but more delicate. Remote controlled fine adjustable offset and shutdown of LV supply Remote control of HV supply and shutdown. Monitoring of the voltage, current and local heatsink temperature Monitoring of the superlayer frontend temperature (PT1000 sensor) http://www.to.infn.it/activities/experiments/cms/fp420/fp420_to.html (LHC4913 STM tol 5kGy) (2.0V and 1.6V, 5W)

Specifications (needs finalization) Detectors: 4 to 5 stations of 10 planes = 5 superlayers each High voltage Drive per detector U= 20 to 150V, with shutdown to 0V I=0 to 1mA Monitor 1V resolution (12bit), Accuracy much worse (5V) 1μA resolution (12bit), Accuracy much worse Low voltage Drive U= 2.0V, U=1.6V Power<10W per station I=0 to 1mA Monitor 10mV resolution (8bit) Current resolution 8 bit.

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. At mechanics meeting 29/9/06 we saw: Space for service electronics. Few meters of cable Radiation level???? Shielding possibility? Thierry Space for electronics needing close proximity to detectors

LV+HV supply blockdiagram for one station Candidate for the crate controller is the solution from ALICE DETECTOR CONTROL SYSTEM (DCS) PROJECT Monitor ADC: Use of the integrated Detector Control Unit, DCUF used in the CMS central tracker for the monitoring of some embedded parameters like supply voltage and currents on the front-end read-out modules. Digital interface is I2C which only reach a few meter so the controller must be close by Control DAC: Currently no suggestion for a DAC. Local control: Rad tolerant FPGA from

LV+HV Crate for 1 station with 8 superlayers=16 hybrids=48 detectors

HV principle diagram V1 Ibias Vin αIbias + Vbias - Cable R3 Pass transistor R1 R2 +R3 R2 Vin αIbias + Vbias - Transformer+rectifier R1 R4 ADC’s Galvanic isolation Use R4 to allow increase of α. DAC Simple linear regulator to make radiation tolerance easier to implement with COTS Monitor, remote control, galvanic isaolated

HV current measurement HV7800 is convenient, but unlikely to be radiation tolerant HV MOSFET is required

Issues to finalize Location of support electronics in tunnel Radiation level to expect. ”Most COTS breaks after few 100Gy” Specification of LV and HV requirements (Volts, Currents, Stabilty, Ripple) Communication interface module in LV supply? Galvanic isolation method within supply modules: Optics or differential signals Communication medium to slow control system: Fiber or cupper? Segmentation within a superlayer. Need for temperature monitor of FE for the cooling system. Where should it be seviced? If in the HV-LV unit, we need define a local interface with cooling Cinzia will supply info about Atlas chips requirements. Mimmo coordinate space location. Post doc to make study on dose rate at fp420. Preliminary report in september.

Critical issues for support electronics (LV and HV) What is the infrastructure and environement in LHC: Location of support electronics in the tunnel Radiation levels at these location Suitable electronics to survive there. Most COTS breaks after few 100Gy Temperature range: Variable from 14 to 30? degree Data communication To quote Scott: The infrastructure in the tunnel is critical: Where is room for service electronics, and what is the environment there? We should look to what has LHC machine done to solve these issues for their support electronics. Posibly use their methods if appropriate. For slow control we have no problems with speed.

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

Alice DCS Alice slow control interface board.

Radiation tests Using the neutron facility in Louvain together with the PMT tests (krzysztof.piotrzkowski@fynu.ucl.ac.be) Test sessions already planned for november and for Januar. We can piggyback on this session with small volume (few liter). But this is neutrons! Is this actually useful?

LV Block diagram This shows a blockdiagram of the LV supply. Modules must be located some meters from the frontend for reasons of space and radiation protection. All electronics should support the environment in the LHCtunnel: Radiation and temperature. The frontend supply (2.0 and 1.6V, <10W) is regulated with a linear regulator. It has remote sense to compensate for line drop. It is likely to be required to adjust the set-voltage remotely during operation. One candidate for regulator is LHC4913 STMicroelectronics. Used in Alice. For reasons of redundancy and electrical isolation, one module for each detector plane or super-plane. Monitor ADC: Use of the integrated Detector Control Unit, DCUF used in the CMS central tracker for the monitoring of some embedded parameters like supply voltage and currents on the front-end read-out modules. Digital interface is I2C which only reach a few meter so the controller must be close by Local processor: Some local intelligence is needed to simplify the communication and perform local house-keeping. Interface to I2C. Suggestions: FPGA’s from Actel, Atmel or micro controller from Aeroflex Control DAC: Currently no suggestion for a DAC Optical interface: Gigabit Optical Link (GOL) (Cern EP/MIC) is probably far to complicated to interface to, so something better has to be found Located in shielded location some meters (3..20m) from frontend One module per plane (superlayer?) for redundancy and noise reasons Remote monitor of V,I and T Remote control of deltaV and power ON/Off Local over-temperture protection ADC 12 bit: Use of the integrated Detector Control Unit, DCUF used in the CMS central tracker is practical.

Notes: Current to voltage shunt converter: ina19X from ti.