PACS - IHDR - MPE – Nov. 12 – 13, 2003 1DSM/DAPNIA/SAp – J. Martignac

PACS – IHDRPACS – IHDRPhFPU DesignPhFPU Design

J. MartignacCEA/DSM/DAPNIA

Service d’Astrophysique

PACS - IHDR - MPE – Nov. 12 – 13, 2003 2DSM/DAPNIA/SAp – J. Martignac

PhFPU DesignINTRODUCTION

•PhFPU Requirements•BFP & PhFPU :

- Design-Thermal & Grounding Scheme- Validation & Qualification

•Critical Items

PACS - IHDR - MPE – Nov. 12 – 13, 2003 3DSM/DAPNIA/SAp – J. Martignac

PhFPU DesignPhFPU Requirements

• Mass around 7 kg.• External Envelope & Mechanical I/F according to the Doc. : PACS-KT-ID-005-iss.4• Admissible Load according to the Doc : PACS-KT-AN-005-iss.2•Thermal Consumption :

- to 12µW at 300mK- to 4,3mW at 2K without the Cooler

PACS - IHDR - MPE – Nov. 12 – 13, 2003 4DSM/DAPNIA/SAp – J. Martignac

PhFPU DesignBFP : Design

The BFP is mainly composed by 5 Sub-assemblies:• the mechanical structure,• the focal plane at 300 mK,• the 300mK thermal strap• the 2K circuit buffer,• the envelope.

PACS - IHDR - MPE – Nov. 12 – 13, 2003 5DSM/DAPNIA/SAp – J. Martignac

PhFPU DesignBFP : Design Review

BFP Specifications BFP Design

DimensionsMass

90x90x80500g / BFP

86x86x70 (without 2K shield Cone)B-BFP : 630g included 2K shield ConeR-BFP : 550g included 2K shield Cone

Thermal Load on 300mk Mech. Structure < 1µWElect. Connections < 1µW

Mechanical Structure : 0,6 µW Elec. Connect. : 0,66 µW

EigenfrequenciesAdmissible Loads

Transv. mode : > 150HzAxial mode : > 150Hz

Transverse mode : 200 HzAxial mode : 500 Hz

Thermal Load on 2K (through 2K/4K Rib. Cabl.)

<5.10-4W Power ON: 4.10-4 W (calculated)Power OFF: 2,4.10-4 W (calculated)

Spectral Bands B-BFP:60-90 µm90-130 µm

R-BFP:130-210 µm

HP filter : High Pass 60 µm + AG filter : Low Pass 130 µm Two Band Pass HP filters on a 2K filter wheel (not SAp delivery) : 60-90µm / 90-130 µm HP filter : High Pass 130 µm + AG filter : Low Pass 210 µm One Band Pass HP filter at the end of the 2K shield Cone located at the pupil

Stray Light FIR Black Coating on critical areas

PACS - IHDR - MPE – Nov. 12 – 13, 2003 6DSM/DAPNIA/SAp – J. Martignac

PhFPU Design

4K Structure

Connector Panel

Cooler Harness Holder

PhFPU : Design

The PhFPU is mainly composed of 8 Sub-assemblies:• the 4K Structure,

PACS - IHDR - MPE – Nov. 12 – 13, 2003 7DSM/DAPNIA/SAp – J. Martignac

PhFPU Design

R & B BFPs Holder

Stainless SteelInsulating Tubes

VoltalefInsulating Spacers

PhFPU : Design

• the 2K Structure,

PACS - IHDR - MPE – Nov. 12 – 13, 2003 8DSM/DAPNIA/SAp – J. Martignac

PhFPU Design

R BFP

B BFP

R&B BFPFilters Boxes

R&B 2K/4K Ribbon Cables

PhFPU : Design

• the two BFPs Red & Blue ,

PACS - IHDR - MPE – Nov. 12 – 13, 2003 9DSM/DAPNIA/SAp – J. Martignac

PhFPU Design

3He Cooler

3He Cooler Harness

L0 Straps BafflingShield Covers

PhFPU : Design

• the 3He sorption Cooler

PACS - IHDR - MPE – Nov. 12 – 13, 2003 10DSM/DAPNIA/SAp – J. Martignac

PhFPU Design

300mK Thermal Strap

Kevlar wires suspension to the 4K

3He Cooler Thermal Interface

R&B BFPsThermall I/F

R&B CopperBraid

Kevlar wires suspension to the 2K

Copper Braid

Stray light Baffling

PhFPU : Design

• the PhFPU 300mK Thermal Strap from the cooler to the BFPs

PACS - IHDR - MPE – Nov. 12 – 13, 2003 11DSM/DAPNIA/SAp – J. Martignac

PhFPU Design

2K Feedthrough (by KT)

R&B BFP L0 I/F

L0 Strap I/F

Copper BraidsStray Light Baffle

PhFPU : Design

• the 2K Thermal Strap,

PACS - IHDR - MPE – Nov. 12 – 13, 2003 12DSM/DAPNIA/SAp – J. Martignac

PhFPU Design

2K Baffle

4K Baffle

PhFPU : Design

• & the Baffles.

PACS - IHDR - MPE – Nov. 12 – 13, 2003 13DSM/DAPNIA/SAp – J. Martignac

PhFPU DesignPhFPU : Design

PhFPU assembly

Status:•Mechanical I/F: OK•Optical I/F: SOAM (KT) •Parts Manufacturing: OK•Integration Tools: OK•Black Paint: in progress•Full Assembly: First Time •Thermal: to be validated

PACS - IHDR - MPE – Nov. 12 – 13, 2003 14DSM/DAPNIA/SAp – J. Martignac

PhFPU DesignPhFPU Thermal Equivalent Scheme

R3

R1Rc3

R6

Rc1

Rc4

PhFPU 2K I/F

PhFPU 4K Structure

PhFPU

élec=2,8mW (B&R BFP)

flex=0,5mWstruct=0,8mW

Feedth.=0,5mWTBC by KT

Evap. Switch I/FT 2K

R2

Rc2

Pump Switch I/F

h0,12W.K-1

Evap.

Pump.

h0,075W.K-1

Global Thermal budget on the L0 level:

- 4,1mW + 0,5mW*

*:(TBC by KT)

L0 Straps manufacturing is under responsibility of Astrium

PACS - IHDR - MPE – Nov. 12 – 13, 2003 15DSM/DAPNIA/SAp – J. Martignac

PhFPU DesignPhFPU Grounding scheme

PumpEvap.

Cooler Structure @ 4K

Space Scraft L0 Thermal Straps

He Tank

Optical Bench

PhFPU Structure @ 4K

BFP Housing @ 2K The PhFPU grounding configuration is like represented:- one shield @ 2K close to the bolometers and signal- one shield @ 4K performed by the outer PhFPU and Cooler Structure- the electrical insulation between the two shields are performed by:

- Voltalef parts at the Structure level- 0,1mm layer of STYCAST 1266 between copper foils at the Thermal Strap level (300mK & 2K)

PACS - IHDR - MPE – Nov. 12 – 13, 2003 16DSM/DAPNIA/SAp – J. Martignac

PhFPU Design Validation & Qualification

Succesful Warm vibrations have been done :- on a BFP Structure alone- at the PhFPU level - & at the Instrument level

A new PhFPU SM has been build for the Cold vibration campaign at CSL.The BFP Kevlar suspensions only survived to the first two axis (Y & Z), and a breakage occured at the beginning of the third run (X).But higher input levels than specified in the IIDA was applied.

PACS - IHDR - MPE – Nov. 12 – 13, 2003 17DSM/DAPNIA/SAp – J. Martignac

PhFPU DesignBFP : Validation & Qualification – Future Tests

Cold vibrations are planed :- on a BFP Structure alone - on a BFP equiped with detectors and its complete readout circuit to validate all the interconnections from the detectors to the end of the 2K/4K Ribbon Cable.

New stiffness measurements at 4K will be done on a BFP Structure in two directions :

- axial (applied load to the focal plane)- transverse ( // to the focal plane)

These tests should be repeated 2 or 3 times on the same Structure to study the thermal cycling influence on the Kevlar wire suspensions.

PACS - IHDR - MPE – Nov. 12 – 13, 2003 18DSM/DAPNIA/SAp – J. Martignac

PhFPU DesignPhFPU : Validation & Qualification – Future Tests

•A complete PhFPU FEM is complete now with the Cooler & the BFP Kevlar suspensions

•Warm vibrations will be done at the PhFPU level to investigate potential coupling between the PhFPU 4K Structure and 3He Cooler:

Cooler SM refurbished with a Titanium core and a functionnal switch linked to a representative L0 Strap: TBC!).

•New cold vibrations campaign under negociation (ESA/Inst).

PACS - IHDR - MPE – Nov. 12 – 13, 2003 19DSM/DAPNIA/SAp – J. Martignac

PhFPU DesignPhFPU Critical Items

Critical:• Qualification at Cold temperature• BFP Kevlar wire suspension• Mechanical load on the Cooler thermal switches I/F

To be validated:• 0,3K Strap thermal behaviour (without & with electrical insulating parts.•Cooler behaviour mounted on the PhFPU (thermal environment)

PACS - IHDR - MPE – Nov. 12 – 13, 2003 20DSM/DAPNIA/SAp – J. Martignac

PhFPU DesignProgress since IBDR

• 3 models of the PhFPU have been built: SMKT, SMKT2 & SOAM

• Warm vibrations done succesfully passed at sub-assembly and at instrument level

• BFP assembly & integration is now completely stabilised• 2K/4K ribbon cables manufacturing is now under control • PhFPU design is complete, all the parts for the QM are

manufactured