AIV 1

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003

PACS

Test Cryostat, OGSE and MGSE

Gerd JakobMPE

AIV 2

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003

Test Equipment and OGSE: Overview

LHe4.2 K

PACSFPU

LN2

77 K

1.7 KLHe

I / F

TESTOPTCS

CR

YO

-B

B1

CR

YO

-B

B2

PACS-Testcryostat

cryostattemp diodesMonitor 218

IEE

E/

RS

232

cryostattemp sensors

Monitor 1TIC 304 M

IEE

E

Monitor 2TIC 304 M

IEE

E

4.2 K LHe-LevelModel 135

IEE

E

1.7 K LHe-LevelModel 136

IEE

E

77 K LN2-LevelModel 186

IEE

E

PressureMonitor

PKR 251

RS

232

Motor driveelectronics

RS

232

TempSensors

Monitor 218

IEE

ER

S 232

BB1Controller 370

IEE

ER

S 232

BB2Controller 370

IEE

ER

S 232

BOLC

DEC/MEC

DPU

SPU

XY-StageControl

RS

232

m3/hm3/hvacuum-pump m3/h

Pumping unit He-pump

ext. BBand

controller

gascell

Hot

plat

e

LENS I/F

PCEA300 K Harness

CSL300 K Harness

testoptics300 K Harness

Scanner3716

Scanner3716

PC"Labview"RS 232IEEE

CR

YO

VA

CC

RY

OV

AC

RS

232

XY Stage

Testoptics4 K Harness

4-30

0 K

Har

ness

AIV 3

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003PACS test cryostat specifications

• Two liquid helium reservoirs: 70l for 4.2K and 13l for 1.7K level• 90l liquid nitrogen for thermal shielding• Optical bench diameter 1060mm, covered by 4.2K thermal shield with

900mm available height for PACS FPU + test optics• Hold time of each temperature level ~48 hours with full PACS operation

(goal)• Specified mechanical, optical and electrical interfaces to PACS FPU and

test equipment • 2 FIR windows for calibration sources input and for optical alignment

checks• 2 window shutter/filter mechanisms at 77K shield • Cryogenic filters at 77K and 4.2K shields to provide predicted Herschel

telescope background• Representative cryogenic harness with ~1100 wires + 227 shields for

FPU, ~124 wires + 20 shields for cryostat and test equipment• Specific mounting rack for different cryostat operation positions, e.g. 30°

tilt for cooler recycling; 90° tilt for shield mounting and cryostat transport.• Provide clean instrument environment, payload integration in cleanroom

class 1000

AIV 4

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003Test cryostat status

• Cryostat built at Cryovac GmbH;MPE’s design specifications fulfilled

• Cryo harness built, integrated with cryostat and tested by MPE in cw31/03

• Several cryo tests performed:-hold time 77K level ~57h-hold time pumped 1.7K level >60h, lowest temperature 1.4K-hold time 4.2K level ~56h, but only without 4.2K-shield!

• Cryostat failed last acceptance test with 4.2K-shield in cw 42/03

• Optical bench temperature too high (6,3K); 4.2K LHe-tank hold time ~24 hours (48h goal); shield temp. 25K

• Heat dissipation on 4.2K level ~1W higher than without 4.2K-shield

• Investigations on a presumable thermal link ongoing; modifications and amendments in progress

• Delivery to MPE for optical alignment of test optics with STM after successful acceptance test, end Nov.03

PACS cryostat in different positions: Overall height ~2400mm, Mounting rack ~1400mm x 2100mm

FPU integration

evacuation operation with 20°tilt

optical bench dia.1060mm cryostat transportation

AIV 5

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003Test optics and Herschel telescope simulator

specifications • Herschel telescope simulator test optics to be integrated with

test cryostat, aligned to PACS FPU and operated at 4.2K• Image quality goal: 3µm wave front error (PACS), field

distortion less than 1 blue photometer detector pixel for the total chopped PACS field of view

• Design of a complex opto-mechanical imaging and baffling system, internal and external calibration sources

• Provision of FIR background based on Herschel telescope temperature of 70K-90K

• 3 cryogenic mechanisms for different internal and external calibration source selection

• 2 internal calibrated cryogenic blackbodies• TUFIR wavelength calibrator in combination with an internal

integrating sphere• TUFIR input in combination with a point source simulator• External blackbody, extended or with point source simulator• Water vapor absorption cell for initial wavelength calibration

AIV 6

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003

Test optics schematic and design

Z

X

TC

T C

H

C

P

C

C

P

T

T

T

T

BB1

BB2

integr.sphere

M D3

chopperw heel

M 6

M 4

M D2

M 1

M 2

flipm irrorm ech.1M D1

align .cube

PACS-FPU

test optics housingand baffling system

liqu id helium

test opticsrig id supportstructure

P1

F3

P2

P3

F4

P4

P5

CW 2

CW 1

M 3

M 5

M 7M 8

1. TUFIR inputintegr. sphere

2. TUFIR inputpoin t source

3. external B B:extented orpoin t source

4. w ater vapour absorption cell w ith BB

alignm ent w ith

externalcalib rationsources:

auto co llim ator

poin t source m askand X/Y translationstage

C

CF

CF

CF

telescopefocus

CF

CTP

c o n t r o lt e m p e r a t u r e r e a d o u t

p o s i t i o n s w i t c h

M D m o t o r d r i v eM m i r r o r

P p u p i lF f o c u sB B b l a c k b o d yC F c r y o g e n i c f i l t e rC W c r y o s t a t w i n d o w

P A C S t e s t c r y o s t a t

4 . 2 K7 7 K

P A C S t e s t o p t i c sG . J a k o b 3 1 . 1 0 . 0 3

F 1

7 7 K1 . 7 K

I F

I F P C I / F

PH

G B 1

G B 2

PHH

F 5

M 9

M 1 0

T

T

T T

G B gear boxhall sensorH

T

A2A1

align .device

A a lignm ent m irror

T T

T

TT

CF

sh

utt

er2

shu

tte

r1

F 2

TC

backgroundheater

aperture4.2K

ligh t cone

3D design of test optics andHerschel telescope simulator

AIV 7

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003Test optics status

• Herschel telescope simulator test optics designed, built and assembled at MPE

• Rigid tripod structure with optics base plate and stray light reducing housing to be integrated with test cryostat

• Interfaces to cryostat, calibration sources and test equipment complete

• Test optics harness parts under final assembly

• Temperature sensors, positions sensors and read outs implemented

• Test equipment available • Integration of 10 mirrors, integrating

sphere, mechanisms and optical alignment is ongoing

• Optical alignment accuracy goal of test optics to PACS FPU within +/- 1 arcmin by means of a minimum of 3 cryogenic tests to be performed in test cryostat

AIV 8

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003

Test optics status ctd.• FIR black coating according KT72-

process applied to test optics housing and components

• 7 temperature sensors on motors, pupil P1, mirrors, structure

• Thermal I/F and cooling straps for PACS FPU manufactured and available

• The MPE developed cryo torquer motor was successfully operated at 4.2K

• Motor life time test with gear box successful at 4.2K

• Chopper wheel performance test at 4.2K to be repeated with reduced friction of angular ball bearing in order to achieve the goal for chopping frequencies up to 2Hz

• Flip mirror mechanisms to be tested at 4.2K in combination with motor/gear

• Alignment and integration is performed in cleanroom class 1000

Test optics and PACS FPU STM

Cryo flip mirror Mechanism1assembly withgear box and cryo torquer motor

AIV 9

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003Internal calibration source: cryogenic blackbody

• Design and manufacturing of 2 identical cryogenic blackbodies for absolute flux calibration and background; devices selected or chopped by test optics chopper wheel

• 18mm opening of cavity adapted to test optics pupils P4 and P5

• FIR coating acc. KT72-process applied• Operational temperature range 4.2K – 80K• Typical temperatures of 10K – 60K can be

stabilized within 35 minutes by a heaterpower of 100mW with controller LS370

• Power dissipation typically 12.5mW at 30K and 35mW at 50K

• Absolute temperature accuracy +/-20mK at 20K and +/-35mK at 50K with integrated calibrated temperature sensor CX-1070 and contr. LS370

• Thermal stability requirement of <+/-1.25mK at 30K and <+/-5mK at 50K feasible

• Status: final assembly ongoing, test equipment available, tests at cryogenic temperature to be performed during test optics alignment checks

MPE design of a cryogenic blackbody

AIV 10

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003External calibration source: TUFIR and I/F

• TUFIR (tunable high resolution coherent FIR radiation source) used for final wavelength calibration and spectral ghost detection

• I/F implemented in test optics design;input through cryostat windows 1 and 2; selected by cryo-mechanisms

• Window 1:-4.2K-aperture for 300K background reduction-f/4.4 light cone for TUFIR beam collection-integrating sphere dia. 80mm for homogenous illumination of pupil P3 and for filling the telescope simulator beam-background heater to simulate Herschel telescope temperatures of 70K-90K

• Window 2:-point source mask in combination with TUFIR located in external focus F2; PACS chopped field of view completely covered-Herschel telescope background simulated by attenuation filter sets on different temperature levels

• Status: test optics I/F available, TUFIR I/F to be defined

Test optics with integrating sphere, 4.2K-aperture and background heater for

TUFIR input through cryostat window1

AIV 11

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003External calibration source: blackbody

• External blackbody in combination with scannable point source simulator for point spread function and grating alignment investigations

• Design of X/Y translation stage and point source simulator finished

• Scanning area covers the complete field of external focus F2

• Reproducibility goal 20µm • Point source simulation pattern to

be PC controlled and synchronized with PACS data read-out

• Calibrated blackbody source and controller available, temperature range 300K – 750K, maximum cavity opening dia. 25mm

• Hot plate alternatively foreseen • Status: manufacturing has been

started

BB

300

K-7

50K

F2

CW 1

PACS test cryostat

test optics

M1

GB gear boxCW cryostat windowCF cryogenic filterMD motor drive

F focus

P pupilM mirror

control

P1

focustelescope

F1

M2

Z

X

YXtransl.stage

PS

PS point source mask

GB1

MD1 mech.1mirrorflip

M3

CF

CF

CF

C

C

C

Schematic of external blackbody set-up (above)and 3D design with pointsource mask on X/Ytranslation stage, aligned with cryostat window2

AIV 12

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003

External calibration source: water vapor source

• Design of a water vapor absorption cell for initialwavelength calibration

• 300mm absorption pathlength and typical watervapor pressure of10-25mbar provide appropriate absorptionlines in the PACSwavelength range

• Alternative gas CO foreseen• Hot plate provides background,

temperature range 300K – 600K• Alignment with external focus F2

at test cryostat window 2 • Status: final design finished end

of Nov.03

M2

flip

mech.1mirror

MD1

P1

M1

M3GB1

focustelescopeF1

CF

CF

CF

ho

t p

late

300

K-6

00K

H2O reservoir

300mm

water vapour absorption cellF2

CW 2

15mbar

pump

50-1mbar

1000-1mbar

test optics

PACS test cryostat

PC I/F

M mirror

P pupil

MD motor drive F focusCF cryogenic filterCW cryostat window

GB gear boxZ

X

IFIF

IF

schematic of the water vapor source set-up (above)and 3D design of absorption cell aligned with cryostat window 2

AIV 13

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003

Mechanical ground support equipment MGSE

Crane with fine drives installed in MPE PACScleanroom class 1000,07/03

Hoisting device for PACS FPU available, used for STM integration06/03

Pumping unit available, containing oil free vacuum and helium pumps,pressure gauges,gas flow meters and vacuum assembly; 10/03

AIV 14

Test Cryostat, OGSE and MGSE PACS IHDR: MPE 12/13 Nov 2003

Mechanical ground support equipment MGSE ctd.

PACS FPU class 1000 transportation containerwith shock absorber,shock and tilt indicators,venting ports; design complete,manufacturing starts 11/03