tips/jim 2008 september 18 the tunable filter imager passes its cdr[s] 2008 march 26-27...

TIPS/JIM 2008 September 18

The Tunable Filter ImagerPasses its CDR[s]

2008 March 26-27 FGS-TFI/Systems CDR2008 Sept. 3 FGS-TFI Etalon CDR

Alex FullertonSTScI / HIA

TIPS / JIM 2008 September 18© Copyright 2008 Her Majesty the Queen in Right of CanadaSubject to Controlled Goods Regulations of Canada

Initial P1 Vibration Test Report

• Etalon P1 underwent a vibration test on Dec 12th, 2007 at COM DEV Cambridge.

• Vibration test report is documented in TRE/CSA/51221/004

• The IUT failed during the final Z-axis vibration approximately 3 seconds into the full level shake.

• The failure occurred at the Baseplate to frame attachment points due to a fracture of the Baseplate.

• A failure assessment was performed and captured in TNO/CSA/51221/039. FIXED!


FGS Optical Assembly – TFI Side

TFI POM on Coarse Focus Mechanism

TFI Collimator TMA

TFI Camera

TMA

TFI Detector Assembly (1 FPA)

TFI SIDECar ASIC

TFI ICP -1

Dual Wheel Assembly

Etalon Assembly

KinematicMounts (3)

Optical Alignment Cubes (2)

TFI POM on Coarse Focus Mechanism

TFI Collimator TMA

TFI Camera

TMA

TFI Detector Assembly (1 FPA)

TFI SIDECar ASIC

TFI ICP -1

Dual Wheel Assembly

Etalon Assembly

KinematicMounts (3)

Optical Alignment Cubes (2)


Fabry-Perot Etalon

Optical path difference = 2µl cos

Phase difference = (2/) 2µl cos + r

µ=index of refraction

m = 2µl cos + r /2

Tuning: For fixed m,

on-axis (=0) l

Detuning: For fixed m, l,

off-axis () cos 1 2/2

Wavelength

Tra

nsm

itta

nce

Gap = 2.25 microns


Capacitance Micrometry


Etalon Mechanical – Etalon Optic Plates

• Made from Topsil HiTran FZ Silicon per SCD 173566

• Plates are ground and polished to λ/30 on etalon (interior) face and λ/30 on exterior face.

• Sensor and track layers are insulated from Si plate material using Si02.

• Sensor tracks are offset to reduce capacitive coupling outside of sensor zones.

• Etalon coatings and sensor deposits covered by RQS/CSA/51221/024

Wire Terminals

Sensor Pad

Multilayer Etalon Coating

Top Etalon Plate

Bottom Etalon Plate

Sensor Track


Etalon Mechanical Components

Optic Core

MountingSystem

RestraintSystem

ActuationSystem

Release BoltBaseplate

Bridge Spacer,PZT Actuator and Gap Spacer

Etalon ShoulderScrew

Load Spreader Washers

Mounting Frame

Cable Mounting Post

PZT Connector

Bridge SpacerAnd PZT Actuator

Release Spacer

Protective Washer

Spring

WasherNutConnector Bracket

Etalon Plates

Terminal Guide Pin

Turret Terminal

Cable Mount


Etalon Mechanical – Actuation System

• Piezo actuators ground and polished to a common height

• Gap spacers must be ground to suit bottom optic plate thickness in order to achieve design gap.

• Springs maintain 80N (nominal) preload after release.

• PFM Piezo Actuators and Gap Spacers will be taped and isolated for launch protection.

PZT Actuator

Protective Washer

Gap Spacer

Spring

Two Wraps Polyimide Tape(Holds GapSpacer to PZT)


Etalon Mechanical – Restraint System

• Low CTE bolt (Invar) works against high CTE spacers (6061-T651) to release 293K preload at ~100K and provide working clearances at 30K

• Bridge spacers are diamond point turned to achieve 30 microns of piezo off-load on launch (293K).

• Top release spacers are pocketed to contain springs from actuation system.

• Operation verified by test per TRE/CSA/51221/003

Release Spacer,Top Plate

Release Spacer,Bottom Plate

Nut

Washer

Bridge Spacer,Bottom Plate

Bridge Spacer,Top Plate

Isolator,Polyimide Tape

Release Bolt


Etalon Mechanical – PZT Wire Routing


Etalon Mechanical – Assembly View

But does it work?


3.39 m Laser Interferometry

/2

/2

• This setup is used in the etalon plate parallelism alignment.

• The 3.39 mm laser setup uses an infrared He-Ne laser, a beam expander, an F/2, f = 75 mm ZnSe lens and an InSb camera operating between 3 and 5 m.

• The expanded beam sent through the etalon is transmitted only if the mirror spacing is a multiple of a half wavelength.

• As a result, an etalon with a wedged gap will transmit parallel lines that are oriented perpendicular to the wedge. The other portions of the beam are reflected back.

• Making the etalon plates parallel consists in transmitting the whole beam across the full aperture (transmitting the missing portions).

3.39 m laser

Beam Expander

LensEtalon InSb Camera

PZT Manual Control

3.39 m Fabry-Perot Setup

PZT Control


Back-Up Material


Optical Layout of the FGS-TFI

20482048 HgCdTe5.2 micron cut-off18 micron pixels


Etalon Coating Design (17 Layers)

65

70

75

80

85

90

95

100

105

110

115

120

1500 2000 2500 3000 3500 4000 4500 5000 2000

2500

3000

3500

4000

4500

5000

5500

6000

6500

7000

7500

Gap (nm)

Wavelength (nm)

Resolution Gap

Non-Functional Waveband

Resolution

m = 3 m = 1

SHORT1500 to 2600 nm~55 filters

LONG3000 to 5000 nm~51 filters


Pupil and Filter Wheels

FLAT Lamp

LINE Lamp

Blocking Filters

CLEAR

Non-Redundant Phase Mask2008 August


Key Performance Requirements

Parent* TFI Requirement Description Requirement Value Current Design Value

FGS-308 TFI Channel FOV > 4.7 sq. arcmin 4.88 sq. arcmin

FGS-638 TFI Pixel Size 65 mas 64.3 to 65.5 mas

FGS-306 TFI Wavelength Range 1.6 – 2.5 m 3.2 – 4.9 m

1.5 – 2.6 m 3.0 – 5.0 m

FGS-311 TFI Spectral Resolution > 70 & < 150 90 to 115

FGS-315 Wavelength Shift in FOV < 1.0% (50% of FOV) < 0.3% (complete FOV)

FGS-317 TFI Sensitivity at 3.5 m 126 nJy 105 nJy

FGS-355 Coronagraphic Capability 2 Pupil masks 2 Lyot occulters

4 Pupil masks 4 Lyot occulters

NIRCam bandpass TFI

bandpass

- Wavelength Selection Flexibility - Good Sensitivity for Emission Line Objects

- Emission Line Diagnostic Imaging - Coronagraphy: Extrasolar Planets, Brown Dwarfs

tips/jim 2008 september 18 the tunable filter imager passes its cdr[s] 2008 march 26-27...

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