Villa Olmo, Como 15-19 October 2001 1 A. Polini

ZEUS MVD Group: Bonn Univ., DESY-Hamburg, DESY-Zeuthen, Hamburg Univ., KEK-Japan, NIKHEF, Oxford Univ., Padova, Torino, Bologna and Firenze Univ. and INFN, UCL.

The ZEUS The ZEUS Micro-Vertex DetectorMicro-Vertex Detector

Alessandro Polini DESY

Villa Olmo, Como 15-19 October 2001 A. Polini2

OutlineOutline

Physics Motivation Physics Motivation Detector DesignDetector Design Standalone Test Measurements Standalone Test Measurements Read-Out, DAQ and Control InfrastructureRead-Out, DAQ and Control Infrastructure First Experience after Installation in ZEUSFirst Experience after Installation in ZEUS Summary and OutlookSummary and Outlook

020406080

100120140160180200

0 20 40 60 80 100Voltage(V)

Current(nA)

14C (bias 51V)17C(bias 48V)20C(bias51V)23C(bias78V)23C(bias65V)30C(bias65V)

Villa Olmo, Como 15-19 October 2001 A. Polini3

A Microvertex for ZEUS at HERAA Microvertex for ZEUS at HERA

ZEUS:upgrade of tracking system: • MVD• Straw Tube Tracker• Global Tracking Trigger

• Tagging of long-lived particles (heavy flavour)

• Reconstruction of secondary vertices

HERA:e± p collider 2001 luminosity upgrade

L= 1.5 7.51031cm-2s-1

•higher sensitivity for very interesting, low cross sections•major changes in interaction region•last bending magnet inside experiment•higher backgrounds, risks of radiation damage

Villa Olmo, Como 15-19 October 2001 A. Polini4

Detector LayoutDetector LayoutForward Section

410 mm

The forward section consists of 4 wheels with 28 wedged sensors/layer providing r- information.

Barrel Section622 mm

The Barrel section provides 3 layers of support frames (ladders) which hold 5 full modules, 600 square sensors in total, providing r- and r-z space points.

e± p

Villa Olmo, Como 15-19 October 2001 A. Polini5

The Upilexconnection foils canbe bent and gluedto the ladder profile

Two half modulesare then glued togetherto form a full module

Five full modules aredisposed over a carbon fibre support

125 mm64

mm

Two single sensorsare glued and electrically connected by gold plated Upilex foils

Barrel MVD: Module and Ladder StructureBarrel MVD: Module and Ladder Structure

Villa Olmo, Como 15-19 October 2001 A. Polini6

Forward MVD LayoutForward MVD Layout

Forward wheels:• 112 Si planes with wedge shape (480 readout strips);• r- measurement;• 1 wheel made of 14x2 detectors;• 4 wheels placed @ z = 311, 441, 571 and 721 mm from IP.

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• n-doped silicon wafers (300 m thickness) with p+ implantations (12 or 14 m wide), HAMAMATSU PH. K.K.

• 512 (480 for forward sensors) readout channels.

• Using the capacitive charge sharing, the analogue readout of one strip every 6 allows a good resolution (<20 m) despite the readout pitch of 120 m.

• Highest coupling to the front end electronics if:

Cc >> Cint > Cb

The charge sharing is a non linearfunction of the interstrip

coordinate x

120 m

Interstrip coordinate x

Cb

Cc Cint

p+ implantation ofThe readout strip

p+ implantation ofthe intermediate strip

particle

20 m

QLEFT QRIGHT

Silicon Microstrip DetectorsSilicon Microstrip Detectors

Villa Olmo, Como 15-19 October 2001 A. Polini8

Front-end and Read-outFront-end and Read-out Front-end Chip HELIX 3.0Front-end Chip HELIX 3.0

– 128 channel analog pipelined programmable readout system specifically developed for the HERA environment.

– ENC[e] 400 + 40*C[pF] (no radiation damage included).– Data read-out and multiplexed over the analog out.– Internal Test Pulse and Failsafe Token Ring (8 chips) capability.

Read-outRead-out– 10 bit resolution ADC Modules with:

Common Mode, Pedestal and Noise Subtraction Strip Clustering 2 separate data buffers: cluster data (for trigger purposes)cluster data (for trigger purposes) and raw/strip data

for accepted events. Global Tracking TriggerGlobal Tracking Trigger

– Together with the Central Tracking Detector: new Global Tracking Trigger System.

1 full module raw data

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Hit Reconstruction: from previous Test Beam Hit Reconstruction: from previous Test Beam ResultsResults

Based on charge sharing

parameterization

Fast algorithmwith no assumption on charge sharing

angle (deg)

Large impact anglesrequire different reconstruction

algorithms

Intrinsic resolution ofa half module

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The MVD System TestThe MVD System Test Following the assembly up to the final MVD, extensive tests and

monitoring of the detector have been performed. A Standalone Test Environment with a dedicated Cosmic Trigger has

been set up.

Large cosmic sample acquired: 2.5 Million triggered events.

Aim: Final checks of modules, cabling, cooling Laser alignment measurements Setup a complete read-out scheme Study detector response with real data Monitoring of various system components:

Cooling, Temperature, Humidity, LV, HV, Noise, Pedestals ,Dark Current.

Villa Olmo, Como 15-19 October 2001 A. Polini11

MVD Cosmic System TestMVD Cosmic System Test Landau distributions from different ladders:

The expected difference in the peak position is clearly seen!

C0L1 (0º) C1L1 (50º)

C0L1

C1L1

S/N 13

Pedestal stable at the level of 1-2 ADC-counts Entries above 20 ADC-counts in noise-distribution: 36 /25 (barrel/forward) Channels with unstable noise-performance: 119 (total for barrel and forward)

Noise and Stability:

Villa Olmo, Como 15-19 October 2001 A. Polini12

MVD Cosmic System Test Results MVD Cosmic System Test Results

~80 m

Withoutany alignmentcorrection

Geometricalefficiency

Cyl. 0 Cyl. 1 Cyl. 2FaultyModules (4 of 206)

First Track fit using all modules but one: resolution ~80 mDominated by systematics, confident to reach final resolution of 20 m

Villa Olmo, Como 15-19 October 2001 A. Polini13

Detector I/V Observed PropertiesDetector I/V Observed PropertiesDuring the system test increasing leakage currents have been observed in some modules. Further studies have shown that at decreasing temperature the relative humidity rises and the breakdown voltage decreases

21.8° 62%h.

22.5° 31%h.A careful checking and control of the humidity is required for the ZEUS MVD!

020406080

100120140160180200

0 20 40 60 80 100Voltage(V)

Current(nA) 14C (bias 51V)

17C(bias 48V)20C(bias51V)23C(bias78V)23C(bias65V)30C(bias65V)

Increasing temperature

Villa Olmo, Como 15-19 October 2001 A. Polini14

MVD Commissioning in ZEUSMVD Commissioning in ZEUS

ZEUS RequirementsZEUS Requirements DAQ System and Global Tracking DAQ System and Global Tracking

Trigger Trigger Radiation MonitorRadiation Monitor First (Cosmic) ZEUS dataFirst (Cosmic) ZEUS data

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The ZEUS DetectorThe ZEUS Detector

bunch crossing time: 96 ns ZEUS: 3-Level Trigger System(Rate 500Hz405 Hz)

e±

27.5 GeV

p920 GeV

Event BuilderEvent Builder

Third Level TriggerThird Level Trigger

cpucpucpucpu cpucpu cpucpu cpucpu cpucpu

CALCAL CTDCTD

Offline TapeOffline Tape

Global Second Global Second Level TriggerLevel Trigger

GSLT Accept/RejectGSLT Accept/Reject

Global First Global First Level TriggerLevel Trigger

GFLT Accept/RejectGFLT Accept/Reject

CTDCTDFront EndFront End

CALCALFront EndFront End

Other Other ComponentsComponents

Other Other ComponentsComponents

CTDCTDSLTSLT

CALCALSLTSLT

CALCALFLTFLT

CTDCTDFLTFLT

~10 ms

5Hz5Hz

40Hz40Hz

500Hz500Hz

101077 Hz Hz

Eve

nt B

uffe

rs

Eve

nt B

uffe

rs

55 s p

ipel

ine

s pip

elin

e

55 s p

ipel

ine

s pip

elin

e

~0.7 s

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Network Connection to the ZEUS Event Builder

(~100 Hz)

The MVD Data Acquisition System and GTTThe MVD Data Acquisition System and GTT

ADCM modules

Lynx OS

CPU

AnalogLinksNIM + Latency Clock +

ControlADCM modules

Lynx OS

CPU

AnalogLinksNIM + Latency

Run Control and OnlineMonitoring Environment

Main MVDDAQ server, Local Control, Event-Builder Interface

Global Tracking Trigger Processors (GFLT rate 800 Hz)

ADCM modules

Lynx OS

CPU

AnalogLinksNIM + Latency Clock+

Control

VME (C+C Slave)Crate 1 (MVD bottom)

Analog Data

MVD HELIX Front-End & Patch-Boxes

Central Tracking Detector Read-out

CTD 2TP modules

Lynx OS

CPU

NIM + Latency

HELIX Driver Front-end

Lynx OS

CPU

GSLT 2TP modules

Lynx OS

CPU

Lynx OS

CPU

VME (C+C Slave)Crate 2 (MVD forward)

VME (C+C Master)Crate 0 (MVD top)

VME TP connection Data from CTD

NIM + Latency

TP connection to Global Second Level

Trigger

Global Second Level Trigger Decision

VME HELIX Driver Crate

Global First Level Trigger,Busy, Error

NIM + Latency

Slow control + Latency Clock modules

Fast Ethernet/ Gigabit Network

VME CPU Boot Server and Control

Clock+Control

MVD VME Readout

Villa Olmo, Como 15-19 October 2001 A. Polini17

The Global Tracking TriggerThe Global Tracking Trigger

Read-out Latency After GTT processing MVD-GTT Trigger Latency

ms

Concept: Combined second level trigger using information from CTD,

MVD (and the new Forward Tracker) Higher quality event reconstruction and rate reduction Z vertex resolution 9 cm (CTD only) 400 m

(MVD+CTD+GTT) Decision required within existing SLT (<15 ms)

Full online latency measurements and data file playback capability.

First average latencies obtained using MonteCarlo events through complete DAQ system and trigger algorithm are encouraging.

Input rate 400Hz

Dijet sampleDijet sample

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•16 PIN diodes in 8 modules ( 1cm2, zfwd=110, zrear=-100 cm) • continuous radiation measurement, beam dump

•8 RADFET (zfwd=200, zrear=-160 cm) • real-time integrating dosimeter:• wide dynamic range 1 mGy to 3kGy

•Thermo-luminescence dosimeters (TLD):• two types (neutron, photon sensitive)• measure precisely integrated dose (monthly exchanged)

The ZEUS Radiation Monitor SystemThe ZEUS Radiation Monitor System

Villa Olmo, Como 15-19 October 2001 A. Polini19

Radiation MonitoringRadiation Monitoring

Proton beam currentIn HERA Increase of

plateau current

PIN diode current

•~50 Gy absorbed so far (diode measurements, confirmed by Radfets & TLDs)

•Final diode readout with beam dump capability being finalized (automatic beam dump at integrated dose of 10..50 mGy per accident).

•Expected background irradiation in 5 years of operation (experiment lifetime): 50 Gy/year = 5 µGy/s

•MVD and readout electronics tested up to 3 kGy, operation still possible, but reduction of S/N

•Max. tolerable dose: 100-300 Gy/year = 10-30 µGy/s

MVD Leakage Current increased

~1A

During machine setupDuring machine setup

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ZEUS Cosmic Data with CTD and MVDZEUS Cosmic Data with CTD and MVDBefore HERA commissioning started (July 2001), there was a short time window for a cosmic data run with the full ZEUS detector.

A Cosmic Event based on a CTD and Calorimeter Trigger.

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Summary and OutlookSummary and Outlook System Test System Test

– Complete MVD-system has been tested continuously for a longer period.– Stable operation of: Slow Control, Cooling, LV and HV Systems.– Dark currents are fairly stable in time at depl. voltage ( dry air flow is

important!)– Pedestal and noise performance is good. Faulty modules <2%.– Cosmic results show expected performance (Landau distributions, etc.).

Installation and Commissioning in ZEUSInstallation and Commissioning in ZEUS – MVD installation was successful (detector integration, cable routing).– Functioning of the DAQ System, the GTT environment as well as the

Control infrastructure established.– Radiation monitoring (active and passive system) available and working

during HERA startup.– Encouraging results looking at the next high luminosity period.