LHCb F. Murtas Servizio elettronica G. Corradi D.Tagnani P.Ciambrone HV_GEM per LHCB M1R1 HV power...

LHCbLHCbF. MurtasF. Murtas

Servizio elettronicaServizio elettronicaG. Corradi D.Tagnani P.CiambroneG. Corradi D.Tagnani P.Ciambrone

HV_GEM per LHCB M1R1 HV power supplyHV_GEM per LHCB M1R1 HV power supply

• IntroductionIntroduction• HV_GEM HV_GEM TechnicalTechnical specification specification• I_meter (for OPERA EXP) I_meter (for OPERA EXP) specificationsspecifications• Final crate Final crate • ConclusionsConclusions



What is an HV_GEMWhat is an HV_GEM

HV_GEM is a new device HV_GEM is a new device designed and realized at designed and realized at Frascati specifically Frascati specifically for the HV power supply of for the HV power supply of GEM detectors.GEM detectors.

This device has been This device has been presentedpresentedat “La Biodola” in May 2006 at “La Biodola” in May 2006 by Gianni Corradi. by Gianni Corradi.



TechnicalTechnical Specification Specification

One HV_GEM device contains :One HV_GEM device contains :• 7 active HV independent channels with serial 7 active HV independent channels with serial

architecturearchitecture

• 6 channels with max voltage of 700 V 6 channels with max voltage of 700 V (200 (200 A)A)

• 1 channel with max voltage of 1200 V 1 channel with max voltage of 1200 V (100 (100 A)A)

• isolation between HV and ground isolation between HV and ground (max 5 KV)(max 5 KV)

• Ripple 1 Vpp at maximum loadRipple 1 Vpp at maximum load

• power supply range power supply range 12-15 Volt12-15 Volt

• power consumption 120 mW (1.2 W at maximum power consumption 120 mW (1.2 W at maximum

current)current)

• CAN-BUS controller CAN-BUS controller

• Read and Write voltages, temperature and PS Read and Write voltages, temperature and PS

monitoringmonitoring

• First channel (G3d) readable in current (1 First channel (G3d) readable in current (1 A A

resolution) resolution)



Scheme of connectionScheme of connection

Vmax -700V

Vmax -500V

Vmax -700V

Vmax -500V

Vmax -700V

Vmax -500V

Vmax -1200V

Gnd Detector

Contr

olle

r

R

G1G1

G2G2

G3G3



HV_GEM Control PanelHV_GEM Control Panel

GEM power supplyGEM power supply

Drift’s fieldsDrift’s fields

Gap’s definitionsGap’s definitions

Voltages Voltages monitoringmonitoring

A program in Labview has been also realized for the monitoring and control purposesA program in Labview has been also realized for the monitoring and control purposes

Two prototypes have been built up to now and they have been already used on GEM chambers in Frascati



OPERA I_meter specificationsOPERA I_meter specifications

• 24 independent channels. • Sensitivity 100pA.• Precision 1% in the range 1nA to 25µA.• Isolation 5KV, no polarity measurement • Maximum drop among input-output 1.2 Volt (current independent) • The system is controlled by a microprocessor with CAN-BUS interface.

This is an evolution of the nano I meter already used by LHCb Muon group in several test beam e construction Test



Some component : Current Some component : Current SensorSensor

Floating Area 5kV max

Optical fiber digital interface

Low voltage floating generator

Bus Communication & PWR



Some component : CAN-BUS Some component : CAN-BUS ControllerController

Logarithmic Digital Decoder

CPU

Serial and CAN.BUS port communications

I/O conn.

JTAG Communication



Very low noise Power supply 100WVery low noise Power supply 100W

Fan connector

Power 220Vac

Isolation transformer

Switching Power Passive Filter

Power controller

+12V +6V

Guaranteed isolation between primary and secondary: 3.5kV



Engineering example Engineering example

LHCb EperimentElectronic service LNF

Power supply for:•Sensor•CPU•HV_GEM



LHCb M1 HV ProposalLHCb M1 HV Proposal

• 24 HV GEM : PS for LHCb M1R1

• 24 HV Output multiple connectors (or 12)

• 24 current monitor channels for G3down

• CAN-BUS communication

• Setting Voltage 24 x 7 = 168 channels

• Current limit set by trimmer (10-200 A)

• Total dimension : standard crate 3U nano I meter

24 HVGEMs modules

standard crate 3 U



ConclusionsConclusions• it has the it has the same costsame cost respect to “CAEN + passive divider” solution; respect to “CAEN + passive divider” solution;

• with the HVGEM system we are able to monitor with the HVGEM system we are able to monitor all the 7 floating voltagesall the 7 floating voltages applied to applied to each detector; each detector; with the passive divider with the passive divider only 3only 3 of them can be monitored; of them can be monitored;

• with the new system we are able to change/adjust the voltage distribution with the new system we are able to change/adjust the voltage distribution among among the three GEM foils of the detector (Vg1, Vg2,Vg3); the three GEM foils of the detector (Vg1, Vg2,Vg3); with the passive divider they are fixed once for everwith the passive divider they are fixed once for ever; ;

• the new system with 24 chs nano-ammeter can be exploited to monitor the new system with 24 chs nano-ammeter can be exploited to monitor the the discharge of the detectors; discharge of the detectors;

• the system allows to limit the currents drawn by each single GEM foil; the system allows to limit the currents drawn by each single GEM foil; with the passivie divider this is not possiblewith the passivie divider this is not possible. .

• the transfer fields (the fields applied on the GEM gaps, between GEM the transfer fields (the fields applied on the GEM gaps, between GEM foils) produced foils) produced inside the detectors by the HVGEM can be kept constant also when gain inside the detectors by the HVGEM can be kept constant also when gain is changed is changed by increasing the voltage applied to GEM foils. by increasing the voltage applied to GEM foils. This feature is of course not present in the HV divider solutionThis feature is of course not present in the HV divider solution; ;

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LHCb F. Murtas Servizio elettronica G. Corradi D.Tagnani P.Ciambrone HV_GEM per LHCB M1R1 HV power...

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