FPU Thermal Qualification, Status and Plans for FM

FPU Thermal Qualification Status 1

PACS IQR 13 Jan 2005

FPU Thermal Qualification, Status and Plans for FM

MPEJ. Schubert

PACS IQR



Content

• PACS Thermal Mathematical Model

• PACS FPU Thermal Behavior ILT



PACS Thermal Mathematical Model

• Update of the PACS TMM performed, 31th August 2004

- HERSCHEL PACS Thermal Analysis, PACS-KT-AN-003, Issue 6

– New Cryostat-TMM (Issue 4)

– New Cooling Strap Design

– Measured Contact Conductances

– Dissipation of Grating, Filter Wheels

– Update of Linear Couplings (0.3 K stage)

- HERSCHEL PACS Cool-Down Analysis, PACS-KT-TN-016, Issue 2

- Reduced Instrument TMM (delivered to ASTRIUM)

- HERSCHEL PACS Description of Reduced Thermal Model, PACS-KT-TN-016, Issue 2



PACS Thermal Mathematical Model• I/F Temperatures

CoolerReq. Evap: 1.85KReq. Pump: 10K

OBReq. 12K @ no loadSepct.Det.Req. Red: 1.75 K



PACS Thermal Mathematical Model

• Heat Flow

• Manly minor changes compared to previous TMM results

Thermal Analysis

Issue 6

Issue 5



2.3 W

1.5 W

1.4 W

0.3 W

CoolerPum p

1.74 K

Shunt

1.66 K

CoolerEvap.

1.78 K

0.3 K -Bolometer

1.78 K

2 K Buffer

1.69 K

Red Spectrometer Detector

1.749 K

Red Spect. CRE

3.97 K 2.5 mW

Filter W heel(B lue Det.)

3.86 K 0.07mW

Chopper

3.89 K 1.01 m W

Calibr. Source 2

75 K 1.2 m W

Filter W heel(Photom eter)

3.63 K 0.02mW

Calibr. Source 1

75 K 1.2 m W

Blue Spectrom eter Detector

2.50 K 1.0 mW

Blue Spect. CRE

4.00 K 2.5 mW

Grating

3.93 K 3.3 mW

PACS Housing (avg.)

3.80 K

PhotometerHousing

3.47 K

Optical Bench: 10.34 K (Center) Total: -10.00 m W

Harness Suspension Struts

Shield: 10.5 K Baffle 44.8 K Total Radiation from Cryostat: 3.00 mW

Lev

el 0

: 1.

65

K

T

ota

l: 3

.32

mW

Lev

el 1

,2 I

/F: 3

.61

KV

entli

ne: 3

.54

K

5.53 mW 4.47 mW

Conduction

RadiationCond. (parasitic)

0.10 mW

0.15 mW

1.00 mW

0.26 mW

11.44 m W

7.09 mW

0.18 mW

2.32 mW

1.44 mW

0.62 mW

1.34 mW

0.12 W

0.9 m W

0.3 m W

0.9 m W

0.3 m W

0.23 mW

2.27 mW

0.47 mW

0.24 mW

0.07 mW

1.01 mW

3.3 m W

1.26 mW

3.0

0 m

W

0.61 mW

0.03 W

0.61 mW

0.39 mW

0.26 mW

Blu

e S

pect

. I/F

: 1.7

05

KR

ed

Spe

ct. I

/F: 1

.67

0 K

Pu

mp

I/F

: 1.

660

KE

vap.

I/F

: 1.6

60 K

Lev

el 1

,1 I

/F:

3.17

KV

ent

line:

3.0

2 K

L1

-To

tal:

22.

48

mW

3.95 mW

0.15 W

2.0 W

0.1 W

0.8 W

0.5 W

2.9 W0.02 mW

Lev

el 1

,3 I

/F: 3

.77

KV

entli

ne: 3

.72

K

0.16 mW

0.2 W

0.10 mW

0.03 mW

1.3 W

2.2 W

9.8 W

2.7 W

CoolerPum p

1.80 K1.54 mW

Shunt

1.69 K

2 K Buffer

1.85 K 3.3 mW

Red Spectrometer Detector

1.70 K

Red Spect. CRE

2.80 K

Filter W heel(B lue Det.)

2.83 K 0.03m W

Chopper

2.89 K 0.96mW

Calibr. Source 2

75 K 1.2 m W

Filter W heel(Photom eter)

2.72 K 0.10m W

Calibr. Source 1

75 K 1.2 m W

Blue Spectrom eter Detector

1.81 K

Blue Spect. CRE

2.81 K

Grating

2.79 K

PACS Housing (avg.)

2.81 K

PhotometerHousing

2.62 K

Optical Bench: 8.44 K (Center) Total: -5.94 m W

Harness Suspension Struts

Shield: 8.6 K Baffle 43.8 K Total Radiation from Cryostat: 2.78 m W

Lev

el 0

: 1.

65

K

T

ota

l: 6

.31

mW

2.66 mW 3.28 mW

Conduction

RadiationCond. (parasitic)

0.07 mW

0.08 mW

3.70 mW

2.06 mW

5.30 mW

3.42 mW

0.08 mW

0.08 mW

0.26 mW

0.29 mW

0.19 mW

0.1 W

0.09 mW

0.09 mW

0.21 mW

0.12 mW

0.96 mW

0.0 m W

0.53 mW

2.7

8 m

W

0.22 mW

3.52 mW

0.19 mW

0.12 mW

Blu

e S

pect

. I/F

: 1.6

60

KR

ed

Spe

ct. I

/F: 1

.65

9 K

Pu

mp

I/F

: 1.

728

KE

vap.

I/F

: 1.6

87 K

2.41 mW

0.1 W

0.7 W

2.8 W

5.5 W

1.54 mW

7.6 W

0.9 m W

0.3 m W

0.9 m W

0.3 m W

0.01 W

Switch on:0.4 m W

Evap.

19.4 W0.30 K

0.11 mW

Lev

el 1

,2 I

/F: 2

.66

KV

entli

ne: 2

.61

KL

eve

l 1,1

I/F

: 2.

44 K

Ve

ntlin

e: 2

.35

K

L1

-To

tal:

11

.13

mW

Lev

el 1

,3 I

/F: 2

.76

KV

entli

ne 2

.72

K

0.1 W

Spectrometer Operation Photometer Operation



PACS Thermal Mathematical ModelS

ligh

tly low

er

alm

ost

unch

an

ged



PACS Thermal Mathematical Modello

wer




wer

or

un

chan

ged



PACS Thermal Mathematical Modelsl

igh

tly low

er

or

un

chang

ed




wer




wer



PACS FPU Thermal Behavior ILT

• Cooler Recycling run successful and frequently performed– Tilt of cryostat 20

degree, evaporator temperature 1.63K, L0 tank at 1.55KL1 tank at 4.2K

– Recycling performed within < 2h

– Nominal operational temperature reached

– Bolometer operational for > 48h

Time

08:00 09:00 10:00 11:00 12:00

Tem

pera

ture

[K]

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

TS_CS_Blue_Det [eng, K] TS_CS_Evap [eng, K] TS_CS_FPU_Struct [eng, K TS_CS_Red_Det [eng, K] TS_Ge_1_8K_tank [eng, K] TS_Ge_4_2K_plate [eng, K TS_Ge_4_2K_tank [eng, K] BOLC_TEMP_EV [eng, K] BOLC_TEMP_SP [eng, K] BOLC_TEMP_TS [eng, K]

Cooler Recycling 27.10.04

08:00 09:00 10:00 11:00 12:00

Tem

pera

ture

[K]

0

10

20

30

40

50

BOLC_TEMP_SP [eng, K]




• During all PACS ILT instrument operations, the specified temperatures were never exceeded

• Dedicated test program have been run during ILT: FPU Thermal Behavior AVM/CQM ILT, PTD 0.7.1

- to determine temperature upper limits during heat dissipation

- to measure temperature transients in the individual FPU subunits,

- to assess overall thermal conductances and heat fluxes,

- to verify proper thermal strapping to cryogenic cooling loops

• During the various tests, the L0 and L1 related temperatures inside the FPU met the requirements and did not exceed limits specified for proper operation.

• No thermal anomalies inside the FPU CQM or in its connection to the different cooling levels are present … except




• Activation of the heater on the blue detector array did not raise the temperature as much as expected (+0.7K).

- Problem very likely triggered by the strong thermal conductance to the LO cooling strap we have to heat against (not confirmed yet)

- Additional cool down necessary to confirm, as for the ILT we decided not to install the thermal shim at the FPU L0 I/F to the blue detector

- For comparison, two SST shims are installed for the upcoming EQM test

- Further cool downs with the FM might be necessary to find the

final shim configuration



Open Work and Planning

• Not all ILT test results available yet

• Results of the ILT will not be fully representative due to different temperature boundary conditions, different concept of the PACS test cryostat and its cooling straps

• Final validation of the TMM can only be done during satellite level testing (PFM phase)

Documents

FPU Thermal Qualification, Status and Plans for FM