space telescope science institute operated for nasa by aura tips / cos tv update 21 december 2006...

SPACETELESCOPESCIENCEINSTITUTE

Operated for NASA by AURA

TIPS / COS TV Update21 December 2006

AgendaAgenda• Testing Setup and StatusTesting Setup and Status• TV Testing PlansTV Testing Plans• Summary Summary • NUV SensitivityNUV Sensitivity• Last TIPS presentation: 15 June 2006Last TIPS presentation: 15 June 2006

Keyes (TIPS) - 21 December 2006Slide 2 of 14

Summary of Test Program to Date

• Completed Environmental Test (TV I) in 2003

• Delivered COS to GSFC in April 2004

• Semi-annual Functional Testing (2004-summer 2006)

• Removed, Inspected, Reworked, & Tested MEB boards from August-September 2006 – including replacing all LVPS

• Integrated all boards back in the MEBs in September 2006.

• COS sucessfully completed Thermal-Vacuum Testing (TV II) in November/December 2006


Previous Ground Testing Status Summary

All major performance requirements met in TV I in 2003All major performance requirements met in TV I in 2003– Spectral resolutionSpectral resolution– SensitivitySensitivity– Flatfield qualityFlatfield quality– Scattered lightScattered light– Wavelength coverageWavelength coverage

TV I testing revealed spectrum drift caused by OSM motionsTV I testing revealed spectrum drift caused by OSM motions– TAGFLASH Mode TAGFLASH Mode (OSM-drift operational correction)

> Test at Thermal-Vac II> Lamp Lifetime Tests ongoing at NIST and CU Lamp Lifetime Tests ongoing at NIST and CU

OSM 1


COS TV Pics


New vacuum CDS New vacuum CDS installed in SES with installed in SES with RAS/Cal, COSRAS/Cal, COS

2006 COS Vacuum Test Configuration

Original Relay Optics, Original Relay Optics, RAS/Cal, TBF and COS RAS/Cal, TBF and COS installed in SESinstalled in SES


COS TV Pics

-- courtesy of

Dave Soderblom


Ground Science Calibration 2006

Science calibration tests in Nov/Dec 2006 TV II test at GSFCScience calibration tests in Nov/Dec 2006 TV II test at GSFC Goals of 2006 test plan (“Appendix C”):Goals of 2006 test plan (“Appendix C”):

– Demonstrate continued nominal performance of COSDemonstrate continued nominal performance of COS– Exercise new modes and capabilities: e.g., Exercise new modes and capabilities: e.g., “TAGFLASH” observing mode“TAGFLASH” observing mode– Obtain additional information needed to reduce and interpret science data: Obtain additional information needed to reduce and interpret science data:

external FUV flat-fieldexternal FUV flat-field observations observations Did not repeat all tests from 2003; only those required to meet above goalsDid not repeat all tests from 2003; only those required to meet above goals Two-tiered test plan: required tests and optional tests to be executed only if Two-tiered test plan: required tests and optional tests to be executed only if

questions arise about the current performance of COSquestions arise about the current performance of COS Close STScI Thermal-Vac Coordination with IDTClose STScI Thermal-Vac Coordination with IDT

– Coordinating Thermal-Vac staffing resources and schedules– FUV and NUV Thermal-Vac data processed by OPUS and ingested in MAST – Initial reference file delivery from IDT prior to SMGT in March 2007


Science Calibration Test Categories

Alignment, focus, image quality, resolutionAlignment, focus, image quality, resolution SensitivitySensitivity Wavelength scalesWavelength scales Flat field and S/NFlat field and S/N Detector functionsDetector functions Optical stability & repeatabilityOptical stability & repeatability Target acquisition algorithmsTarget acquisition algorithms TAGFLASH TAGFLASH


TV II Science Cal Tests

• 29 test sequences; items in red are new tests for 2006.• Total run time is approximately 11 days for required tests and 21 days for required+contingency.

1111-1121 FUV spectra of PtNe lamp1161-1191 NUV spectra of PtNe lamp1210-1230 FUV sensitivity measurements1250-1295 NUV sensitivity measurements1300-1391 FUV external flat-field

2250 NUV spatial resolution2300-2350 Grating stability, FUV & NUV3300-3310 BOA transmission & resolution3500-3550 OSM1 & OSM2 position checks

4000 FUV line spread function5000-5500 Tag-flash test

850 Repeatability monitor

1410-1475 Target acquisition1700-1750 Internal flat-fields

2745 FUV detector optimization2805-2810 High local count rates

2950 NUV resolution at FUV PSA offsets

Required Tests Contingency Tests


Thermal Vac & Science Calibration

Initial thermal vacuum and thermal balance testing in NovemberInitial thermal vacuum and thermal balance testing in November STScI support at GSFCSTScI support at GSFC

– Hartig, Wheeler, Soderblom, Keyes, Hartig, Friedman. Hartig, Wheeler, Soderblom, Keyes, Hartig, Friedman. Detailed science calibration (“Appendix C”) 28 Nov – 8 Dec.Detailed science calibration (“Appendix C”) 28 Nov – 8 Dec.

– ~25 tests; 1233 data files; ~10 Gbytes raw data.~25 tests; 1233 data files; ~10 Gbytes raw data.– Included STScI-generated SMS for thorough TAGFLASH testingIncluded STScI-generated SMS for thorough TAGFLASH testing

> First execution of an STScI SMS on SI. First execution of an STScI SMS on SI. All testing completed at GSFCAll testing completed at GSFC Science calibration completeScience calibration complete

– All primary instrument modes exercised.All primary instrument modes exercised. Preliminary onsite assessment indicates performance remains nominalPreliminary onsite assessment indicates performance remains nominal

– Continuing assessment of resolution, sensitivity, alignment, image quality, focus.Continuing assessment of resolution, sensitivity, alignment, image quality, focus.– Apparent decline in NUV sensitivity between 2200 and 2900 Apparent decline in NUV sensitivity between 2200 and 2900 Å with ONLY the two bare Å with ONLY the two bare

aluminum-coated spectral elements (G225M and G285M)aluminum-coated spectral elements (G225M and G285M) Flight software and TAGFLASH performed as expectedFlight software and TAGFLASH performed as expected Continued storage at GSFC; SMGT upcoming (30 March 2007)Continued storage at GSFC; SMGT upcoming (30 March 2007) Functional tests every 3 months; NUV throughput tests every 6 monthsFunctional tests every 3 months; NUV throughput tests every 6 months OPUS-processed data will be available with StarView.OPUS-processed data will be available with StarView.


% change: 2006 Sensitivity compared with 2003 Sensitivity

• 2003 and 2006 test setup may have systematic differences

• Different PMT calibrations

• Red-leak in 2003 PMT measurements

• No common optic or detector between NUV TA1, G230L and FUV G140L, G160M yet show same ~10% decline decline in common wavelength region; implies external systematic offset


NUV

NUV Limiting Flux for S/N=10 in 3600 sec (R~10,000 (0.24 _ ) binning)

-15.5

-15.0

-14.5

-14.0

-13.5

-13.0

-12.5

1600 1800 2000 2200 2400 2600 2800 3000 3200

Wavelength (_ )

log Flux (erg cm

-2 sec

-1 _

-1)

COS G185MR~16,000-20,000

COS G225MR~20,000-24,000

COS G285MR~20,000-24,000

STIS G230MR~9000-17,000

STIS E230MR=30,000

STIS sensitivities assume zero slit losses; typical loss is ≥20%.


COS offset by apparent 20% NUV decline

NUV Limiting Flux for S/N=10 in 3600 sec (R~10,000 (0.24 _ ) binning)

-15.5

-15.0

-14.5

-14.0

-13.5

-13.0

-12.5

1600 1800 2000 2200 2400 2600 2800 3000 3200

Wavelength (_ )

log Flux (erg cm

-2 sec

-1 _

-1)

COS G185MR~16,000-20,000

COS G225MR~20,000-24,000

COS G285MR~20,000-24,000

STIS G230MR~9000-17,000

STIS E230MR=30,000


Sensitivity

Analysis of FUV and NUV sensitivity is very preliminary at this pointAnalysis of FUV and NUV sensitivity is very preliminary at this point Statistically significant sensitivity degradation between 2003 and 2006 for Statistically significant sensitivity degradation between 2003 and 2006 for onlyonly G225M and G285M G225M and G285M spectral elements spectral elements

– These are the only gratings with bare aluminum coatingsThese are the only gratings with bare aluminum coatings– Degradation is not uniform with wavelengthDegradation is not uniform with wavelength

> No degradation since 2003 at 2100 No degradation since 2003 at 2100 Å whereÅ where degradation may have stabilized degradation may have stabilized– Even with measured degradation, COS retains significantly higher throughput Even with measured degradation, COS retains significantly higher throughput

than STIS E230M and the COS MAMA is predicted to have a factor of 4 lower than STIS E230M and the COS MAMA is predicted to have a factor of 4 lower backgroundbackground

– Spare NUV gratings and witness samples will be evaluatedSpare NUV gratings and witness samples will be evaluated Possible amelioration?Possible amelioration?

– very difficult to access OSM2 mechanism and NUV gratingsvery difficult to access OSM2 mechanism and NUV gratings


Background information


FUV Sensitivity


COS Optical Layout


COS Detectors – FUV XDL

Top View

170 mm


COS Detectors – NUV MAMA

in the enclosure


CC BB AA CC BB AA

PtNePtNeWavecalWavecal

ExternalExternalScienceScience

NUVNUVMAMAMAMA

FUV MCP (1 of 2 segments)FUV MCP (1 of 2 segments)

External Science

Internal PtNe Wavecal

COS Spectral Layout for Simultaneous Internal Wavecals and Science Spectra

– Obtain (continuous or flashed) internal PtNe spectra at same time as science exposure

– Track internal PtNe lines and apply shifts to science spectrum (all events time-tagged) in COS data pipeline

space telescope science institute operated for nasa by aura tips / cos tv update 21 december 2006...

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