Development and Performance of the High Voltage Distribution System for the ALICE TRD A. Markouizos, P. Mantzaridis, P. Mitseas, A. Petridis, S. Potirakis,

Development and Performance of the Development and Performance of the High Voltage Distribution System High Voltage Distribution System

for the ALICE TRDfor the ALICE TRD

A. Markouizos, P. Mantzaridis, P. Mitseas,A. Markouizos, P. Mantzaridis, P. Mitseas,

A. Petridis, S. Potirakis, M. Tsilis, M. VassiliouA. Petridis, S. Potirakis, M. Tsilis, M. Vassiliou

University of AthensUniversity of Athens

HEP 2008, Ancient OlympiaHEP 2008, Ancient Olympia

1. Introduction

2. HVDS Overview

3. HVDS Commissioning

4. Performance Tests

Magnetic field test

Test on the TRD-SMI / SMII

5. Summary

Outline

XXVI Workshop on Recent Developments in HEP M. VassiliouXXVI Workshop on Recent Developments in HEP M. Vassiliou

TRD


4

TRD

Introduction

540 individual modules:18 azimuthal sectors-supermodulesEach supermodule contains:

5 detector stacks of 6 module layers each Each module consists

of:

ALICE TRD


• radiator• drift chamber• readout electronics

TRD Supermodule


HVDS Description

A Master/Slave power supply distribution system has been designed and constructed in order to provide the required anode (1.9kV) and drift voltage (-2.5kV) to the ALICE TRD readout chambers. The system can switch on and off, monitor (at the nA level), protect, and regulate (leverage of 1000 Volts) each channel from a common ceiling voltage.


HVDS Overview

High Voltage Distribution System:Simple design

Reduced complexityReduced number of components

Very low current circuits: Meet ALICE TRD requirementsProvide high resolving power (nA), fast

response,Short circuit protection

Two Enfolded Voltage stabilizing Systems:Shunt regulator

Provides load regulationReduces output ripple

Software regulationGives long term stabilityXXVI Workshop on Recent Developments in HEP M. VassiliouXXVI Workshop on Recent Developments in HEP M. Vassiliou

Architecture Similar to ALICE TRD layout

Card Channel 01Channel 02Channel 03Channel 04Channel 05Channel 06

μCpu

Crate 01

Module 01

Module 02

Module 03

DCS Board

Card 01

Card 02

Card 05

. . . . .

HVDS Architecture


HVDS SpecificationsBoth Systems:

Output Channels 180ramp-up rate 1-30 V/sramp-down rate 1-100 V/sHV stability <0.1% /24hAchieved HV stability ~0.002%/24hRipple rejection ~40 dBCurrent accuracy <0.2%Achieved Current accuracy ~0.03% response time < 50 ms

Anode System:Dynamical range 900 – 1900 VMax. current 7 uA

Drift System:Dynamical range 1450 – 2500 VMax. current 270 uA

HVD Card Block Diagram1. Six shunt regulators

2. DACs for the regulator reference voltage

3. Six measurement circuits, each consisting of an ADC with the appropriate signal conditioning circuits for voltage and current measurement.

4. Six floating auxiliary power supplies.

5. The micro-controller and the CPLD

6. The CAN BUS interface (controller and line driver)

7. RS232 interface

8. A digital temperature sensor

9. IP Switches that set the card ID on the CAN BUS


Software Regulation:HV Stability ~0.002% /24h

Includes protections:Temperature, Current, and VoltageGenerates alarm signalsResponse Time <50ms

Performs Self Diagnostics:Hardware Monitoring, Hardware Error

Detection

2 Control Interfaces: CAN Interface (PVSS & Final Set-up)RS232 Interface (Development, Debugging,

Tests)

Control Software: Embedded Software


DCS: SM HV Control Panel


Set: status voltage max (min)_voltage max_current periodMonitor: voltage currentOpen panels ramping alarm historyWarnings – AlarmsLocal Archiving

DCS: HVDS Channel FSM Panel


2 Anode + 2 Drift Crates delivered and tested at CERN:

30 Anode + 30 Drift HVD Cards

180+180 Output HV Channels

to power 6 TRD Supermodules

HVDS Commissioning I


Each crate contains:

HVDS Commissioning II

• 1 Backplane• 15 HVD cards• 1 DCS Board

adapted on 1 DCS Auxiliary Card

• 8 Auxiliary Power Supply Cards provide AC power to the isolated channels of the HVDS

Cards

• 4 LV Power Supplies (Schroff PSM112 for ±12V and PSG105 for +5V)


HVDS Commissioning III


HVDS Commissioning: HVD Card Image


• Tests performed in the MNP22

Facility at CERN.

• HV set at -2.4 kV (Drift), 1.8 kV

(Anode)

• B increased from 0 to 220 Gauss

• Two crate configurations

• Successful over current test

Performance Tests : Magnetic Field Test


Results: Drift HVD @ -2.4 kV

magnet on magnet offσ < 15 mVσ < 15 mV

Magnetic Field Test


Results: Anode HVD @ 1.8 kV

magnet on magnet offσ < 15 mVσ < 15 mV

Magnetic Field Test


Test on the TRD-SM I


Performance TestsLong Term Voltage Stability Test

•ΔV (FWHM) < 30 mV

•ΔV / V < 1.6 E-5

HV set at 1900 V



• 6 anode channels • HV set at 1450 V

HVD System



Cosmic Data took at CERN

“After finalising the assembly of the super module, its performance was tested with cosmics tracks. Three scintillators were arranged so that high multiplicity cosmics events could be recorded with a rate of about two per minute. The drift chambers were filled with an Ar, CO2 (15%) mixture and high voltage was applied by a Master/ Slave distribution system specifically developed at the University of Athens, Greece (drift voltage 1450V, anode voltage 1450 V). “C. Adler et al. “Construction of the First ALICE TRD Super Module”, GSI Scientific Report 2006

Figure 1: Cosmics tracklets in the six layers of stack three of the super module. The tracklets can be connected to form tracks. A simple reconstruction (clusterization) was applied. We show a projection of the found clusters onto the plane perpendicular to the z-axis (beam axis).


• HVD system connected with the SM-II

• Anode voltage @ 1.45 kVDrift voltage @ -1.5 kV , -1.9 kV

• Successful overcurrent test

Test on the TRD-SM II


Results

σ < 15 mVσ < 15 mVDrift HVD @ 1900 V

Test on the TRD-SM II


Anode HVD @ 1450 V

Summary

A High Voltage Distribution System for the ALICE TRD hasbeen designed and constructed. Four HVDS Crates have been delivered.

The system consists of the hardware, the embedded software and the control software at the supervisory level.

Many tests performed at CERN verified that the system fulfils all the specifications set by the detector designers.


References

[1] P. Mantzaridis, A. Markouizos, P. Mitseas, A. Petridis†, S. Potirakis, M. Tsilis, M. Vassiliou, “A High Voltage Distribution System for the ALICE Transition Radiation Detector”, ALICE-INT-2008-006, https://edms.cern.ch/document/901555/1

[2] A. Markouizos, P. Mantzaridis, P. Mitseas, A. Petridis, S. Potirakis, M. Tsilis, M. Vassiliou, “The ALICE TRD – HV Distribution System”, Proc. of the Workshop on the DCS for the TRD, CERN, November 2007

[3] A. Markouizos, P. Mantzaridis, P. Mitseas, A. Petridis, S. Potirakis, M. Tsilis, M. Vassiliou, “Performance Tests of the TRD – HVDS” ALICE DCS Workshop, CERN, October 2007, http://indico.cern.ch/getFile.py/access?contribId=17&resId=1&materialId=slides&confId=21162

[4] A. Markouizos, P. Mantzaridis, P. Mitseas, A. Petridis, S. Potirakis, M. Tsilis, M. Vassiliou, “Integration of the HV Distribution System to the First TRD Supermodule”, Proc. of the Workshop on the DCS for the TRD, Heidelberg, January 2007.

[5] C. Adler et al. “Construction of the First ALICE TRD Super Module”, GSI Scientific Report 2006 http://www.gsi.de/informationen/wti/library/scientificreport2006/PAPERS/INSTRUMENTS-METHODS-39.pdf

[6] A. Petridis, S. Potirakis, M. Tsilis, M. Vassiliou, “The TRD HV Distribution System”, ALICE - DCS Workshop, CERN, March 2005, http://alicedcs.web.cern.ch/AliceDCS/Meetings


Thank you!


HVDS Crate Structure

TRD Principles

Documents

Development and Performance of the High Voltage Distribution System for the ALICE TRD A. Markouizos, P. Mantzaridis, P. Mitseas, A. Petridis, S. Potirakis,