Photoconductor Detector Arrays 1

PACS IBDR 27/28 Feb 2002

Photoconductor Detector Arrays

IBDR

Hilmar Richter • ANTEC-GmbH • Germany

Günter Bollmann, Peter Dinges, Otto Frenzl, Heidrun Köppen, Heribert Krüger, Claudia Popp

Photoconductor Detector Arrays 2

PACS IBDR 27/28 Feb 2002Overview

• Modul / Array Interfaces– Optical Interface– Electrical Interface

• Design Implications on Arrays– Detector Stack– Thermal Budget– Cryo Cycling and Vibrational Load

• Achieved Performance– Cut-off Wavelengths– Bias dependency

• PA / QA Activities: Flow Plan• Procurement• Summary

Photoconductor Detector Arrays 3

PACS IBDR 27/28 Feb 2002Optical Interface of the “Red” Array

Radial arrangement of 25 high stress modules in groups of 5 modules. The center of the radial arragement is 240 mm in front of the fore optics in the plane of the pupil.

Photoconductor Detector Arrays 4

PACS IBDR 27/28 Feb 2002Electrical Interface

Interface design• FEE and harness substrate are supported by kapton tubes in order to reduce

thermal load to the module • All wires from interface parts to the module are stainless steel, wires between

interface parts are gold wires• The nano connector of the pigtail harness is glued to the harness substrate• Thermal loads of the interface parts flow through the cooling strap to the 4 K

level

Photoconductor Detector Arrays 5

PACS IBDR 27/28 Feb 2002Detector Stack in the Cavity and Final Bias Design

Ball segment

Detector contact

Ge:Ga crystal

Detector contact

Gold wire 25 µm

Insulator

Final design• Bias concept has been changed to prevent grounding of

detectors by short circuit– Contact diameter decreased at the ball segment

side to prevent grounding of the signal line (2) – Contact diameter increased at the ground side

(this contact is grounded directly to the module (1)

Slits reduced from 30 - 70 µm to 10 - 40 µm and therefore less cross talk

1

2

Detector Stack

Photoconductor Detector Arrays 6

PACS IBDR 27/28 Feb 2002Thermal Budget

4 K

P = 375 µW

P = 624 µW

11 µW 202 µW 162 µW 7 µW 134 µW 108 µW

P = 249 µW

25 High Stress Modules 25 Low Stress Modules2.5 K1.7 K

4 K

16 Detector Wires (Steel)

4 Long FEE + 2 Long Harness Posts (Kapton)

2 Short Harness Posts (Kapton)

Photoconductor Detector Arrays 7

PACS IBDR 27/28 Feb 2002Cryo Cycling and Vibration Load

• Slit of 0.2 mm between kapton tube and support part (no gluing) at the free bearing support posts compensates shrinkage of different materials (module, FEE / harness substrate, kapton tube, etc.) during cool-down.

After cool-down: slit = 0 - 0.05 mm.

• Static tests at LN2 temperatures prove: Kapton tubes withstand deflections of 0.15 mm (0.12 mm) perpendicular (parallel) to the substrate plane. The applied forces correspond to accelerations of 110 g.

• Above support post design passed cryo cycling and vibration tests with qualification load levels.

Free bearing support post

Slit

Photoconductor Detector Arrays 8

PACS IBDR 27/28 Feb 2002Specification Cut-off Wavelength

0 50 100 150 200 250 3000,0

0,2

0,4

0,6

0,8

1,0

1,2 U15mV U30mV U43mV U49mV

Re

l. re

spo

nsiv

ity

(µm)

Specification high stress module: CW > 200 µm @ 40 mV

30 mV

2 4 6 8 10 120

5

10

Specification

Variation ofcutoff wavelength

(

µm)

QM # - HS

Photoconductor Detector Arrays 9

PACS IBDR 27/28 Feb 2002Specification Cut-off Wavelength

12 14 16 18 20 22 24

125

130

135 Min Max

CW

(µm

)

QM # - LS

12 14 16 18 20 22 240

1

2

3

4

5

6

7

8 Variation ofcutoff wavelength

(

µm)

QM # - LS

Specification low stress module: CW <130 µm @ 100 mV

Photoconductor Detector Arrays 10

PACS IBDR 27/28 Feb 2002PA / QA Activities: Flow Plan

KIP

Final check of the completed module before shipping

Cleaning and incoming inspection

of all parts

Detector stack assembly and RSR measurement.

KIP: Check of detector stack

KIP

Final cleaning of the module and check with

UV light

Preparation of FEE / harness substrate

support posts

Gluing of the pigtail harness to the harness substrate and implementation

of connector saver and short circuit connector

Integration of FEE / harness substrate, wiring and fixing of

FO

Photoconductor Detector Arrays 11

PACS IBDR 27/28 Feb 2002Procurement / Assembling

• Status of parts procurement for the integration of QM modules

- Delivery of the Gore cables 19.03.2002

- Tecnologica announced connector savers and short circuit connectors for 10.05.2002

- Delivery of FEE and harness substrates 19.04.2002

- PO for the pigtail harness from Cannon placed 22.02.2002 (delivery time 12 weeks)

• Routinely going on assembly of FM modules at Antec

Time critical: Procurement of pigtail

harness

Photoconductor Detector Arrays 12

PACS IBDR 27/28 Feb 2002Summary

• Interfaces to MPE housing, KT board and IMEC FEE and harness substrate defined

• Module design finished (specifications fulfilled)

• Procurement of integration parts initiated and delivery dates fixed