FLITECAM: The first light camera for SOFIA

Amanda Mainzer, I. S. McLean, T. Aliado, E. E. Becklin, G. Brims, J. Goulter, E. Kress, N.

Magnone, J. Milburn, G. Skulason, M. Spencer

UCLASPIE • 27 August 2002

AKM 2 SPIE 27 Aug. 2002

FLITECAM Team

• Dr. Ian McLean, Principal Investigator

• Amanda Mainzer, Instrument Scientist

• Ted Aliado, Mechanical/Fabrication

• Dr. Eric Becklin, SOFIA Project Scientist

• George Brims, Systems Engineering

• John Goulter, Mechanical/Regulatory

• Evan Kress, Mechanical

• Nick Magnone, Mechanical/Fabrication

• John Milburn, Software

• Gunnar Skulason, Electronics

• Michael Spencer, Electronics

UCLA:

AKM 3 SPIE 27 Aug. 2002

FLITECAMSummary

• First Light Test/Experiment CAMera/ for SOFIA• Features:

– 1- 5 µm with InSb 1024 x 1024 array

– FOV: 8´ diameter (inscribed on detector)

– Scale: 0.47´´ per pixel

– LHe/LN2 system

– Grism Spectroscopy (R~2000)

– Co-mounts with HIPO

• First light: ~Q3 2002 (ground based) • Delivery to SOFIA: Q1 2004• Must be fully FAA certified

Y(side)

X(aft)

Z(up)

AKM 4 SPIE 27 Aug. 2002

FLITECAM’sField of View

• Originally going to use 512x512 array

• Between PDR and CDR, switched to 1024x1024 array to image the entire 8 arcmin SOFIA field of view

AKM 5 SPIE 27 Aug. 2002

OpticsModes: - Imaging

- Grism (R~2000) - Pupil viewing

Optical design:- Collimator triplet- F/5 imaging camera- 4 fold mirrors- Dual filter wheel- 3 pupil viewing lenses- Filters: ZJHKK’LM + selected narrow band

AKM 6 SPIE 27 Aug. 2002

Image Quality• SOFIA seeing ~2-3 arcsec

• FLITECAM PSF: 0.2 - 0.5 arcsec across entire 8 arcmin field of view

• FLITECAM designed to fully evaluate SOFIA image quality Box = 2x2 pixels

1 pixel = 0.47 arcsec

AKM 7 SPIE 27 Aug. 2002

ThermomechanicalOptical Design

• Large crystal lenses have to be cooled in controlled fashion to avoid thermomechanical shock

• Collimator: LiF, BaF2, ZnS all with diameter ~165 mm

• Spring-loaded “finger” mounts isolate lenses and prevent thermomechanical shock

• Lenses manufactured by Brad Picirillo of Optical Solutions Inc. of New Hampshire

LiF lens Spring-loaded “fingers”

AKM 8 SPIE 27 Aug. 2002

Thermomechanical Performance

•Large LiF and BaF2 lenses particularly susceptible to thermal & mechanical shock

• Spares difficult & expensive to obtain - 9 month lead time!

• To verify success of our mounting/thermal isolation scheme, we constructed a dummy collimator

AKM 9 SPIE 27 Aug. 2002

Dummy Collimator

77 K end

Thermometers: front center, front edge, back edge

LiF spare lens

Glass blanks

~165 mm

•Brad Picirillo of OSI provided spare unpolished LiF lens for dummy collimator

• Put in two additional glass blanks to simulate thermal characteristics of BaF2 and ZnS lenses

• Epoxied thermometers to spare LiF: front/back center, and front edge

• Additional thermometers on collimator housing and optical baseplate

• This allowed us to monitor gradients vs. cooldown rate

AKM 10 SPIE 27 Aug. 2002

ThermomechanicalOptical Design cont’d.

• Cooldown rates controlled by isolating selected components with G10

• Time constants calculated and measured to determine safe rates

• Thanks to Brad Picirillo of OSI for providing spare LiF!

• Will eventually test spare LiF to destruction

• Results show that cooldown rates of up to 13 K/hr are safe!

LiF Lens Gradients vs. Temperature

-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

50100150200250300

Temperature (K)

Tem

per

atu

re D

iffe

ren

tial

(K

)

;

Edge to center gradientFront center to back center gradient

AKM 11 SPIE 27 Aug. 2002

Warm First Light• To avoid long iterative cryogenic cycles, found focus warm

• Confirmed warm focus with warm Zemax optical model

• Warm best focus location agreed with warm focus model to within depth of focus

• Set focus to predicted cold focus location

AKM 12 SPIE 27 Aug. 2002

Completed Software

• Java platform-independent

• Software controls temperature sensors, vacuum gauge, helium level sensor, detector heater, and mechanisms

• Astronomical Observation Requests (AORs) will be written using a modified version of SPOT (SIRTF Planning and Observation Tool)

AKM 13 SPIE 27 Aug. 2002

Electronics

• Detector head and electronics purchased from Mauna Kea Infrared

• These systems are being packaged into 19” racks for ground-based operations:

– Data acquisition system– Mechanism controllers– Temperature controllers– Pressure monitors– LHe level monitor– Power controller

Multiplexer CW Rack SHARC Processor

On-Cryostat Electronics

AKM 14 SPIE 27 Aug. 2002

Cryogenics

• LN2/LHe cryostat manufactured by Precision Cryogenics of Indianapolis, IN

• 20 L of LN2, 20 L of LHe

• FAA regulations: cryostat can only be filled when plane is on the ground

• Will fill before each night’s observing

• Cylindrical design dictated by SOFIA volume allocation

• Cryostat can either look up or horizontal - can be used on ground

AKM 15 SPIE 27 Aug. 2002

DAR witnessed testing at PCI on 28 March 2002

LN2 Container Pressure Test

• measuring the deformation of container under pressure

• checking conformance with drawings

FLITECAMFAA Cryogen Container Testing

AKM 16 SPIE 27 Aug. 2002

FLITECAM Assembly

AKM 17 SPIE 27 Aug. 2002

Milestones

CY 01 CY 02

CY 03

CY 041 2 3 4 5 6 7 8 9 101112 1 2 3 4 5 6 7 8 9 101112 1 2 3 4 5 6 7 8 9 101112 1 2 3 4 5 6 7 8 9 101112

1 2 3 4 5 6 7 8 9 101112 1 2 3 4 5 6 7 8 9 101112 1 2 3 4 5 6 7 8 9 101112 1 2 3 4 5 6 7 8 9 101112

ORR9/28

IT & V Phase

Optics

Electronics

Software Development

System Level Tests

Cryostat

Delive

r

y

Aug01

Delive

ry

Jan 0

2

Delive

ry

Q4-01

Design

Comple

te

Q2-01

FLITECAM - HIPO

Integration TestingApr 03

Top Level SOFIA Milestones

FY01>

Fwd BulkheadComplete

AircraftStructures mod.Complete

TA GroundAcceptance

OFRReview

Obs. Flt.Test Done

Perf. FlightTest

FLITECAM Cryostat8110-3 20/9/01

FLITECAM Del’yto SSMOC 3/30/04

FLITECAM Acceptance 10/1/04

Integrationand test

Integration and test

Alignment and test

Integrationand test

Telescope DeploymentAug 02

FLITECAM/HIPO Deploymentto JAITV Jun 03

Test &Review

FLITECAM/HIPO INTEGRATION

Ongoing Software development and Validation

First Light in Lab?

AKM 18 SPIE 27 Aug. 2002

Commissioning• Three fall observing runs scheduled at 3-m Shane Telescope at Lick Observatory

• Shane telescope’s F/17 optics well-matched to SOFIA’s F/19.6

• First run starts Sept. 13!

• Will observe a variety of star forming regions

• Observations will constitute part of A. Mainzer’s Ph.D. thesis