initial alignment check / calibration in vacuum dennis ebbets with substantial contributions from...

Initial Alignment Check / Calibration in Vacuum

Dennis EbbetsWith substantial contributions from Tom Delker, Erik Wilkinson, Steve

Osterman, Ken Brownsberger, Rich Brewster, Brian McLaughlin

May 02, 2003Updated after selection of NUV setup positions

Previous versions:

Apr 04, Feb. 27, 2003 Dec 04, Nov 26, Nov. 22, Oct 30, Sep 20, 2002

2

This package contains• Description of contents and sequence of tests for initial calibration in

vacuum phase.• These descriptions are inputs for the development of Real-Time (RT)

commanding or Science Mission Specification (SMS)• Plan for operational implementation is indicated in blue text for each test.• Estimates of time requirements are included. These are meant to be total

times, exposure + instrument overheads. Exposure times will be shorter than the times that appear in these tables.

• Test details developed in ‘Initial Alignment Check & Calibration in Vacuum.xls’

• Descriptions of the calibration tests are transferred from this development document to Appendix A of the COS Thermal Vacuum Test Procedure

3

Initial Alignment Checks and Calibration in VacuumFUV and NUV activities separated to allow for different waits after pumpdown

Test Plan High level allocations

Operations Test # Activity # 8 hr shifts equiv.days

Install COS and Rascal 2.0 0.67RASCAL to COS metrology 1.0 0.33Align CDS to RASCAL 1.0 0.33 "Bottoms-Up"COS ambient functional 1.0 0.33 Individual test estimates

RT TA1 aperture scans 0.5 0.17 Total setup times from "initial alignment checks & calibration"pre-pumpdown checkout 0.5 0.17 including pump-down includes transitions to/from SAFE

8 hr shifts dayspumpdown 3.0 1.00 9.0 3.00 # 8 hr shifts equiv.days

verify CDS to RASCAL alignment 0.5 0.17 0.50 0.17abbreviated vacuum SYSFUNC test 1.0 0.33 1.00 0.33

RT 50 NUV TA1 COS aperture scans 0.5 0.17 0.50 0.17RT 60 NUV focus sweeps 0.5 0.17 0.50 0.17

RT & SMS 150 NUV External Pt-Ne lamp spectra 1.0 0.33 1.25 0.42SMS 250 NUV Cal SS flat-field lamps 1st light 0.5 0.17 0.23 0.08SMS 325 NUV Cal SS wavecal lamps 1st light 0.5 0.17 0.83 0.28RT 375 Optional NUV focus sweeps 1.0 0.33 0.00 0.00RT 450 NUV Level I Sensitivity Measurements 1.0 0.33 0.67 0.22

SMS 525 NUV External D2 lamp spectra 1.0 0.33 1.10 0.37SMS 825 NUV FPSPLITs 0.5 0.17 0.54 0.18

RT 70 FUV focus sweeps 1.0 0.33 0.50 0.17RT 100 FUV External Pt-Ne lamp spectra 1.0 0.33 0.58 0.19

RT & SMS 200 FUV Cal SS flat-field lamps 1st light 0.5 0.17 0.41 0.14RT & SMS 300 FUV Cal SS wavecal lamps 1st light 0.5 0.17 0.45 0.15

RT 350 Optional FUV Focus Sweeps 1.0 0.33 0.50 0.17RT 400 FUV Level I Sensitivity Measurements 1.0 0.33 0.74 0.25RT 500 FUV External D2 lamp spectra 1.0 0.33 0.65 0.22

SMS 800 FUV FPSPLITs 0.5 0.17 0.61 0.20

RT 550 Transmission of CDS ND filters 0.5 0.17 0.79 0.26SMS 600 Cal SS flat-field lamps 2nd light 0.5 0.17 0.47 0.16SMS 700 Cal SS Pt-Ne lamps 2nd light 0.5 0.17 Total data times 0.89 0.30 Total data timesSMS 850 COS Repeatability Monitor 1.0 0.33 Without Reserves 0.49 0.16 Without Reserves

8 hr shifts days 8 hr shifts days17.0 5.67 14.2 4.73

Unallocated Reserve 13.0 4.33

Total after pumpdown 30.0 10.00

Schedule allocation 10.00one shift per day 10.0two shifts per day 20.0three shifts per day 30.0

4

Activities in air prior to pump-down

• Install COS and RASCAL in Rambo

• RASCAL to COS alignment using metrology

• CDS relay optics to RASCAL entrance aperture alignment

• Verify CDS and RASCAL operability before pump-down

• COS turn-on and ambient Functional Test• Test #40TA1 aperture scan (Verifies alignment of RASCAL to COS with light)

– RT commanding based on prior alignment phase activities

• Pump-down

5

CDS relay optics to RASCAL alignment • One mirror in CDS relay optics is motorized and can be operated remotely to steer

the beam onto the RASCAL entrance aperture.• Coarse Alignment

– Goal is to cover RASCAL input aperture with CDS light spot– Use Pt-Ne lamp on CDS lamp-only channel

• Use CDS ND filter and lamp current to adjust brightness– Inspect alignment by eye if possible– Use CDS video camera if necessary

• Fine Alignment– Use RASCAL reference detector to peakup alignment – Adjust for ~1000 cts/sec with nominal point-source aperture– Verify operability and use of RASCAL reference detector– Verify each RASCAL input aperture for common alignment to CDS Relay

Optics– Verify expected throughput of each aperture

6

Verify CDS and RASCAL operability before pump-down

• Exercise CDS Pt-Ne lamp with monochromator. Verify presence and count rates for emission lines 2200Å < < 3200Å using RASCAL detector. Won’t see shorter wavelengths in air.

• Adjust monochromator input and output slit widths to give at least 10s of cts/sec in lines planned for NUV sensitivity calibration. This may use a RASCAL aperture larger than a point-source, but not large enough to overfill the COS PSA.

• Exercise CDS Pt-Ne lamp-only channel

• Exercise CDS ND filters

• No absorption cell for this phase

• Establish confidence that both CDS and RASCAL are ready to support operations

7

COS turn-on and ambient functional test

• Verify that COS is hooked up correctly and ready to take data

• Use standard version of ambient functional test. Not a calibration specific test.

– Functional test may include only very short exposures with calibration subsystem lamps at this point. Count rates with COS optics and detectors are unknown. No useful data expected from internal lamps, other than that they turn on.

8

Test #40 TA1 Aperture Scan

• RT commanding based on prior alignment phase activities• Align RASCAL to COS using light prior to pump-down• Adjust aim of RASCAL beam and/or COS aperture block to ensure that light

enters COS PSA• Use NUV TA1 time-tagged exposure (little FUV in air)• Use CDS Pt-Ne lamp at 1000 cts/sec on RASCAL PMT

– use ND filters + lamp current to adjust brightness• Scan RASCAL steering mirror if necessary and possible

– 5x5 square raster for coarse alignment– 11x11 cross scan for fine alignment

• Scan aperture block location• Find combination of RASCAL steering mirror and COS aperture block that

provides best illumination and good NUV image quality.• This will be the starting point for measurements in vacuum.

9

Example of coarse and fine scans(Can RASCAL can do this?)

x x x x x

x x x x x

x x x x x

x x x x x

x x x x x

5x5 coarse rastersteps ~radius of PSAfind single brightest point

x x x x xx x x x x x x x x x x x x x x x

11x11 fine rastersteps TBD ~1/5 radius of PSAfind brightest point in X and Y

10

Pumpdown

• Final verification of COS and RASCAL readiness

• Shutdown

• Final verification of vacuum chamber and support equipment readiness

• Pumpdown

11

Post-pumpdown verification of CDS relay optics to RASCAL entrance aperture

alignment• Repeat pre-pumpdown alignment check of CDS to RASCAL using

reference detector

• Confident that CDS and RASCAL are working properly in vacuum

• Confident that CDS - RASCAL are properly aligned to get light into COS

• May be done while waiting for pressure to decrease to safe level for COS turn-on

12

COS Vacuum Functional Test

• Wait for vacuum chamber pressure to fall below 10-5 Torr

• Wait for COS internal pressure monitor to indicate safe level– 10-4 Torr before opening FUV door

– 10-5 Torr for NUV HV operations

– 10-6 Torr for FUV HV operations

• If pressure is falling slowly, can we skip FUV HV ops in FT and proceed with initial NUV activities?

• COS Vacuum FT to verify operability. This may be an abbreviated version of the full test.

• VFT may include observations of all four internal calibration lamps. Exposure times and current levels will not be optimized yet. Don’t expect much useful data.

13

Tests #50 and #60TA1 aperture scan and focus sweep

• RT commanding based on prior alignment phase activities• Repeat RASCAL and COS aperture scans of test #40 to establish

optimum centering of light into COS• Use CDS Pt-Ne lamp on lamp-only channel• Use fused silica long-pass filter to limit wavelengths to only NUV• Use CDS ND filters and lamp current to adjust count rate• Find optimum OSM1 linear stage position for NUV focus as indicated

by TA1 image• Update operations software for future NUV tests

• Time has been reserved for these activities. Details of procedures have not been defined in the calibration plan. Use Tom Delker’s HOMS procedure as starting point.

Estimate 0.5 shifts for each test needed for data acquisition.

14

Test #150 NUV External Pt-Ne lamp spectra

• Level I Spectral Resolution• Level I, II Wavelength Coverage and Wavelength Scale• Configure COS to aperture and OSM positions derived from results of tests #50 and #60• First COS spectra in vacuum over entire NUV wavelength range• CDS Pt-Ne lamp on lamp-only channel, fused-silica filter blocks FUV• RASCAL 10m aperture for most observations• Adjust count rate to ~10000 cts/sec on RASCAL detector with fused-silica filter, but no

bandpass filter in place• Record external spectra for each NUV grating (no FP-SPLITs), PSA

– SMS operation for this phase– Use 6 setups that “paint the spectrum” for each M grating, 3 for G230L

• Record image of 10m aperture with TA1 and TA1-BRT• Record image of double 4m aperture with TA1• Record spectra through 10m aperture and BOA with G230L

– RT operation for these three

15

Analysis of Test #150• Plot spectra, identify lines• Assess focus, 2D images, 1D line profiles, resolution• Determine whether adjustments or additional measurements such as focus sweeps are needed• Measure location of spectra on detector, define subarray locations• Determine whether spectra of all gratings fall within the range expected to be covered by a

single flat-field exposure.• Derive wavelength calibration solutions• Determine wavelength ranges and central wavelengths for each grating and stripe• Goal is to have minimum set of 6 setup positions cover the entire wavelength region ie

“paint the spectrum”• Update OSM2 position tables if necessary• Assess count rates for planning science calibration times• Look for second order images in NUV• Measure BOA/PSA transmission ratio vs wavelength• Determine of double aperture images are oriented in cross-dispersion direction as desired for

spatial resolution test later.

16

Test #150 NUV External Pt-Ne lamp spectra

Sequence and time

4 SMS’s

RT

No internal wavecal lampsNo FPSPLITs

activity minutes hours

turn on COS, NUV, PSA 40 0.67turn on RASCAL, 10m aperture 30 0.50activate CDS, fused silica filter 15 0.25Pt-Ne lamp-only channeladjust CDS to RASCAL alignment 30 0.50adjust count rate 15 0.25

G185M c = 1817 15 0.25G185M c = 1850 15 0.25G185M c = 1882 15 0.25G185M c = 1921 15 0.25G185M c = 1953 15 0.25G185M c = 1986 15 0.25



G230L c = 2635 15 0.25G230L c = 3000 15 0.25G230L c = 3360 15 0.25

reduce lamp brightness 5 0.08TA1 10 0.17TA1-BRT 10 0.17

change to RASCAL double aperture 30 0.50adjust count rate 15 0.25

TA1 image of double aperture 15 0.25

return to RASCAL 10m aperture 30 0.50

configure COS BOA 15 0.25increase lamp brightness

G230L c = 3000 15 0.25

Return to SAFE 10 0.17

total time with startup & shutdown 10.00 hoursnumber of 8 hour shifts 1.25 shifts

without startup & shutdown 7.67 hoursnumber of 8 hour shifts 0.96 shift

17

G185M OP-01 v22 positions

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

1700 1750 1800 1850 1900 1950 2000 2050 2100

Wavelength A

Se

tup

po

sit

ion

Stripe A Stripe B Stripe C

1786

1817

1835

18501864

1882

1890

1900

1913

1921

1941

1953

1971

1986

2010

18


0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

2100 2150 2200 2250 2300 2350 2400 2450 2500

Wavelength A

Se

tup

po

sit

ion

Stripe A Stripe B Stripe C

2186

2217

2233

22502268

2283

2306

2325

2339

2357

2373

2390

2410

19


01

23

456

789

1011

121314

1516

1718

2500 2600 2700 2800 2900 3000 3100 3200

Wavelength A

Set

up

po

siti

on

Stripe AStripe C

2617

2637

2657

2676

2695

2709

2719

27392850

2952

2979

2996

3018

3035

3057

3074

3094

20

G230L OP-01 v 22 positions

0

1

2

3

4

5

1600 1800 2000 2200 2400 2600 2800 3000 3200

Wavelength A

Se

tup

po

sit

ion

2635

2950

3000

3360

Stripe A Stripe B

21

Test #250NUV Cal Subsystem flat-field lamps 1st light

• Level I Flat-field Lamp Operation• No external lamp, no CDS, no RASCAL operations• SMS operations• Move aperture block to allow spectrum of flat-field aperture to overlap

region of PSA as defined by results of test #150• First measurement of count rates with calibration subsystem flat-field

lamps in vacuum (unless vacuum FT provided data)• Exposure times of 100 seconds should be adequate• Measure NUV count rates with medium current only. High current may

be a contamination risk at this early time.• Measure count rates for one setup position for each “M” grating, 1850,

2250, 2850. Measure count rates in all three stripes for each grating. G185M is expected to be brightest.

22

Test #250 analysis• Assess suitability of nominal flat-field scheme:

– NUV with G185M and either lamp at high current– Extrapolate from medium current count rates

• Verify that flat-field data covers location of all spectra– compare pixel region covered by these FF data with regions

covered by PSA science data from test #150• Simulate combining 4 FP-SPLIT exposures if S/N allows• Verify suitability for use as pixel to pixel flats if S/N allows• Plan 2nd light exposures, thermal balance test measurements and

science calibration phase measurements• Estimate flat-field exposure times needed for flats to support science

spectra with S/N = 30, 100• Check current and ND selections

23

Test #250NUV Cal Subsystem flat-field lamps 1st light

Order may be adjusted to optimize operational efficiency.


turn on COS, NUV, FCA 40 0.67

G185M c = 1850 FF#1 medium 10 0.17G185M c = 1850 FF#2 medium 10 0.17





without startup & shutdown 1.00 hoursnumber of 8 hour shifts 0.13 shifts

24

Test #325NUV Cal Subsystem Pt-Ne lamps 1st light

• Level I and II Wave Cal Lamp Operation

• No external lamp, no CDS, no RASCAL operations

• SMS operations

• Assume 5 minutes total time for each measurement. Exposure time + overhead for mechanism movement.

25

Analysis for Test #325

• Plot spectra and identify lines• Compare two lamps, three current levels

– Any lines missing at lowest currents?– Look for bright contaminant lines or bands

• Derive wavelength calibration coefficients, apply to previous observations of external lamp & check accuracy

• Select best combination of lamp and current for wavecals of each grating setting

• Plan exposure times to give optimum exposure depth and number of lines for wavecals

• Plot lamp temperatures during operations

26

Test #325NUV Cal Subsystem Pt-

Ne lamps 1st light

Order may be adjusted to optimize operational efficiency.


turn on COS, NUV, WCA 40 0.67

G185M c = 1817 line #1 medium 10 0.17G185M c = 1850 line #1 medium 10 0.17G185M c = 1882 line #1 medium 10 0.17G185M c = 1921 line #1 medium 10 0.17G185M c = 1953 line #1 medium 10 0.17G185M c = 1986 line #1 medium 10 0.17

G185M c = 1850 line #2 medium 10 0.17


G225M c = 2250 line #2 medium 10 0.17


G285M c = 2709 line #2 medium 10 0.17

G230L c = 2635 line #1 low 10 0.17G230L c = 3000 line #1 low 10 0.17G230L c = 3360 line #1 low 10 0.17G230L c = 3360 line #1 medium 10 0.17G230L c = 3360 line #1 high 10 0.17

G230L c = 2635 line #2 low 10 0.17G230L c = 3000 line #2 low 10 0.17G230L c = 3360 line #2 low 10 0.17G230L c = 3360 line #2 medium 10 0.17G230L c = 3360 line #2 high 10 0.17

TA1 line#1 low 10 0.17TA1 line#2 low 10 0.17

TA1-BRT line#1 low 10 0.17TA1-BRT line#2 low 10 0.17




27

Test #375Optional NUV Focus Sweeps

• RT operations

• Time is reserved for additional adjustments needed to optimize either RASCAL or COS alignments to achieve best image quality.

• Contents of this test will be defined after analysis of data from tests #50, #60 and #150.

28

Test #450NUV Level 1 Sensitivity Measurements

• Level I Spectroscopic Effective Area• Level I TA1 Mode Target Acquisition

• RT operations• Pt-Ne lamp with monochromator and RASCAL reference detector, count

rate ~1000 cts/sec on RASCAL detector• Use 100m pinhole. RASCAL aperture may be larger than point source

pinhole, but image may not overfill PSA. • 1 for each NUV grating near expected peak sensitivity. Use a wavelength

at which PMT was calibrated at LASP. If time permits additional wavelengths can be measured.

• Nominal instrument setup, PSA, time-tagged• Validate procedures• Verify sensitivity acceptable to CEI specs

29

Analysis of Test #450

• Derive throughput, in counts/photon, for each NUV grating

• Compare to range of expectations from models and component testing

• Compare to performance required by CEI

• Check for stray light artifacts away from main image.

30

Test #450NUV Level 1 Sensitivity Measurements


turn on COS, NUV, PSA 40 0.67turn on RASCAL, 100m aperture 30 0.50activate CDS, fused silica filter 15 0.25Pt-Ne monochromator channel 0.00adjust CDS to RASCAL alignment 30 0.50adjust count rate 15 0.25

G185M c=1850 1846 in stripe B 30 0.50G225M c=2268 2262 in stripe B 30 0.50G285M c=2952 2830 in stripe A 30 0.50G230L c=3360 2262 in stripe A 30 0.50TA1 2487 30 0.50TA1-BRT 2487 30 0.50




31

Test #525NUV External D2 lamp spectra

• SMS operations. May be same SMS as used for test #150. Separate SMS for each grating.

• This is a D2 lamp on the CDS lamp-only channel, not one of the calibration subsystem lamps

• Measure spectrum of D2 lamp as seen with COS resolution– 10m RASCAL aperture– All NUV gratings– Use minimum number of setup positions that “paint the spectrum”

• Determine if extent of spectrum of CDS D2 lamp on detector is suitable for use as flat-field data set– Largest RASCAL input aperture– G185M for NUV

32


• Plot all spectra• Compare to cal subsystem spectra with same gratings to assess FCA

smearing of emission line structure as measured with cal subsystem flat-field lamps in test # 250.

• Concatenation of data from adjacent wavelength regions allows a crude assessment of uniformity of sensitivity across segments or stripes as indication of need for “L Flats”

• Assess suitability of external D2 spectra with large RASCAL aperture to provide data for high S/N (~100) flat-field maps. If so, data will be taken with external lamp rather than cal subsystem lamp during ground testing. This would be done to use the external lamps rather than the internal lamps for very long exposures during ground test.

• RASCAL may also be defocused to provide additional blurring of the emission line structure.

33

Test #525NUV External D2

lamp spectra

4 SMS’s


turn on COS, NUV, PSA 40 0.67turn on RASCAL,10m aperture 30 0.50activate CDS, fused silica filter 15 0.25D2 lamp only channel 0.00adjust CDS to RASCAL alignment 30 0.50adjust count rate 15 0.25use CDS 170nm filter




G230L c = 2635 15 0.25G230L c = 3000 15 0.25G230L c = 3360 15 0.25

Configure RASCAL largest aperture 15 0.25adjust count rate 15 0.25

G185M c = 1817 15 0.25G185M c = 1882 15 0.25G185M c = 1986 15 0.25




1 SMS

34

Test #825NUV FP-SPLIT Spectra

• Level II FP-SPLITs• SMS operations• Measure offsets between subexposures using one standard FP-SPLIT exposure for each NUV

grating– G185M 1850, G225M 2250, G285M 2850, G230L 3000

• Use CDS lamp-only channel with Pt-Ne lamp• Leave lamp on for duration of test. Software should close the shutter during wavecal

exposures and OSM motions.• Use STScI standard wavecal exposure strategy for “auto FP-SPLIT”• Use RASCAL 10m aperture for external Pt-Ne lamp

35


• Assess algorithms for combining subexposures– The primary goal is to test the ability to combine the four subexposures

without degrading spectral resolution.

– Measure offsets between subexposures. Is a single constant sufficient, or is the offset dependent on grating, stripe, pixel or wavelength?

– This is not intended to be a demonstration of the ability of FP-SPLITs to increase the S/N

• Assess auto FP-SPLIT operational procedures– Sequence of wavecal and external target exposures

– Shutter operations

• Derive and apply wavelength scales, assess accuracy– Zero-point shift could be beam centering in aperture

– Look for errors correlated with stripe, pixel or wavelength

36

Test #825NUV FP-SPLIT Spectra


turn on COS, NUV, PSA 40 0.67turn on RASCAL, 10m aperture 30 0.50activate CDS, fused silica filter 15 0.25Pt-Ne lamp-only channel 0.00adjust CDS to RASCAL alignment 30 0.50adjust count rate 15 0.25

NUV G185M FPSPLIT + wavecal 30 0.50NUV G225M FPSPLIT + wavecal 30 0.50NUV G285M FPSPLIT + wavecal 30 0.50NUV G230L FPSPLIT + wavecal 30 0.50




1 SMS

37

Test #70FUV focus sweeps

• RT operations. Use procedures developed during prior alignment phases.• Determine optimum positions of OSM1 rotary and linear stages to

produce best focus for each FUV grating– G130M central wavelength = 1309– G160M central wavelength = 1600– G140L central wavelength = 1230

• Use CDS Pt-Ne lamp on lamp-only channel• Remove fused silica filter to allow FUV wavelengths• Use CDS ND filters, FUV bandpass filters and lamp current to adjust

count rate to 5000 cts/sec on RASCAL PMT• Use RASCAL 10m aperture, or 4m if image is bright enough• Update operations software for future FUV tests

Estimate 0.5 shifts needed for data acquisition.

38

Test #100 FUV External Pt-Ne lamp spectra

• Level I Spectral Resolution• Level I, II Wavelength Coverage and Wavelength Scale• RT operations• Configure COS to aperture and OSM1 positions derived from results of test #70• First COS spectra in vacuum over entire FUV wavelength range• CDS Pt-Ne lamp on lamp-only channel (no internal lamps)• RASCAL 10m aperture – close to point source• Adjust count rate to ~10000 cts/sec on RASCAL detector using FUV bandpass

filters in CDS, lamp current and ND filters• Record external spectra for each FUV grating

– 1 central wavelength for each grating– no FP-SPLITs– PSA

• Covers full wavelength range of all FUV gratings with PSA• Record external spectra through BOA with G140L

39

Analysis of Test #100• Plot spectra, identify lines• Assess focus, 2D images, 1D line profiles, resolution• Determine whether adjustments or additional measurements such as

focus sweeps are needed• Measure location of spectra on detector, define subarray locations• Determine whether spectra of all gratings fall within the range

expected to be covered by a single flat-field exposure.• Derive wavelength calibration solutions• Determine wavelength ranges and central wavelengths for each

grating and segment• Update OSM1 position tables if necessary• Assess count rates for planning science calibration times• Measure BOA/PSA transmission ratio vs wavelength

40

Test #100 FUV External Pt-Ne lamp spectra


turn on COS, FUV, PSA 105 1.75turn on RASCAL, 10m aperture 30 0.50activate CDS, no fused silica filter 15 0.25Pt-Ne lamp-only channeladjust CDS to RASCAL alignment 30 0.50adjust count rate 15 0.25

FUV G130M central wavelength = 1309 15 0.25FUV G160M central wavelength = 1600 15 0.25FUV G140L central wavelength = 1230 15 0.25

configure COS BOA 15 0.25

FUV G140L central wavelength = 1230 15 0.25




No use of internal wavecal lamps.

No FP-SPLITs

41

Test #200FUV Cal Subsystem flat-field lamps 1st light

• Level I Flat-field Lamp Operation

• Short RT count rate check followed by

• SMS operations

• Move aperture block to allow spectrum of flat-field aperture to overlap region of PSA as defined by results of test #100

• First measurement of count rates with calibration subsystem flat-field lamps in vacuum (unless vacuum FT test provided good data)

• Exposure times of 100 seconds should be adequate

• Measure FUV count rates with configuration expected to be used for routine flat-field observations

42

Test #200 analysis• Assess suitability of nominal flat-field scheme:

– FUV seg A with G130M and either lamp at medium current– FUV seg B with G160M and either lamp at low current

• Verify that flat-field data covers location of all spectra– compare pixel region covered by these FF data with regions covered by PSA

science data from test #100• Assess smearing of line structure in FUV if S/N allows• Simulate combining 4 FP-SPLIT exposures if S/N allows• Verify suitability for use as pixel to pixel flats if S/N allows• Plan 2nd light exposures, thermal balance test measurements and science

calibration measurements• Estimate flat-field exposure times needed for flats to support science spectra with

S/N = 30, 100• Check lamp current and ND filter selections• Plot temperatures during exposures

43

Test #200FUV Cal Subsystem flat-field lamps 1st light

Order may be adjusted to optimize operational efficiency

Add RT checks to sequence


turn on COS, FUV, FCA 105 1.75CDS off & shutter closed

G130M central wavelength = 1309 FF#1 low 10 0.17G160M central wavelength = 1600 FF#1 low 10 0.17G130M central wavelength = 1309 FF#2 low 10 0.17G160M central wavelength = 1600 FF#2 low 10 0.17

G130M central wavelength = 1309 FF#1 med 10 0.17G160M central wavelength = 1600 FF#1 med 10 0.17G130M central wavelength = 1309 FF#2 med 10 0.17G160M central wavelength = 1600 FF#2 med 10 0.17exposure times are 100 seconds each




44

Test #300FUV Cal Subsystem Pt-Ne lamps 1st light

• Level I and II Wave Cal Lamp Operation

• Short RT checks of count rates, followed by

• SMS operations

• Assume 5 minutes total time for each measurement. Exposure time + overhead for mechanism movement.

45

Analysis for Test #300

• Plot spectra and identify lines• Compare two lamps, three current levels

– Any lines missing at lowest currents?– Look for bright contaminant lines or bands

• Derive wavelength calibration coefficients, apply to previous observations of external lamp & check accuracy

• Select best combination of lamp and current for wavecals of each grating setting

• Plan exposure times to give optimum exposure depth and number of lines for wavecals

• Plot lamp temperatures during operations

46

Test #300FUV Cal Subsystem Pt-Ne lamps 1st light


Add RT checks to sequence


turn on COS, FUV, WCA 105 1.75CDS off & shutter closed

G130M c = 1309 line#1 medium 10 0.17G160M c = 1600 line#1 medium 10 0.17G140L c = 1230 line#1 medium 10 0.17G140L c = 1230 line#1 low 10 0.17G140L c = 1230 line#1 high 10 0.17

G130M c = 1309 line#2 medium 10 0.17G160M c = 1600 line#2 medium 10 0.17G140L c = 1230 line#2 medium 10 0.17G140L c = 1230 line#2 low 10 0.17G140L c = 1230 line#2 high 10 0.17




47

Test #350Optional FUV Sweeps

• RT operations

• Time is reserved for additional adjustments needed to optimize either RASCAL or COS alignments to achieve best image quality.

• Contents of this test will be defined after analysis of data from tests #70 and #100.

48

Test #400FUV Level 1 Sensitivity Measurements

• Level I Spectroscopic Effective Area• Level I TA1 Mode Target Acquisition

• RT operations• Pt-Ne lamp with monochromator and RASCAL reference detector,

count rate ~1000 cts/sec on RASCAL detector• RASCAL aperture may be larger than point source pinhole, but image

may not overfill PSA. Use 100m diameter aperture.• 1 for each FUV segment near expected peak sensitivity. If time

permits additional wavelengths may be meaured.• Nominal instrument setup, QE grid on, PSA, time-tagged• Validate procedures• Verify sensitivity acceptable to CEI specs

49


• Derive throughput, in counts/photon, for each grating

• Compare to range of expectations from models and component testing

• Compare to performance required by CEI

• Examine 2D data for stray light artifacts away from main image

50

Test #400FUV Level 1 Sensitivity Measurements


turn on COS, FUV, PSA 105 1.75turn on RASCAL, 100m aperture 30 0.50activate CDS, no fused silica filter 15 0.25Pt-Ne monochromator channeladjust CDS to RASCAL alignment 30 0.50adjust count rate 15 0.25

G130M c = 1309 1327 on Seg A 30 0.50G130M c = 1309 1248 on Seg B 30 0.50G160M c = 1600 1621 on Seg A 30 0.50G160M c = 1600 1430 on Seg B 30 0.50G140L c = 1230 1327 on Seg A 30 0.50




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Test #500FUV External D2 lamp spectra

• RT operations, with careful adjustment of count rate using RASCAL detector prior to COS exposure. Use FUV bandpass filters, ND filters and lamp current. Try for ~10000 cts/sec with RASCAL PMT.

• This is a D2 lamp on the CDS lamp-only channel, not one of the calibration subsystem lamps

• Measure spectrum of D2 lamp as seen with COS resolution

– 10m RASCAL aperture– All FUV gratings, one setup position each

• Determine if extent of spectrum of CDS D2 lamp on detector is suitable for use as flat-field data set– Largest RASCAL input aperture, wide open– G130M, G160M for FUV

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• Plot all spectra• Compare to cal subsystem spectra with same gratings to assess FCA

smearing of emission line structure• Concatenation of data from adjacent wavelength regions allows a

crude assessment of uniformity of sensitivity across segments or stripes as indication of need for “L Flats”

• Assess suitability of external D2 spectra with large RASCAL aperture to provide data for high S/N (~100) flat-field maps. If so, data will be taken with external lamp rather than cal subsystem lamp during ground testing. This would be done to use the external lamps rather than the internal lamps for very long exposures during ground test.

• RASCAL may also be defocused to provide additional blurring of the emission line structure.

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Test #500FUV External D2 lamp spectra


turn on COS, FUV, PSA 105 1.75turn on RASCAL, 10m aperture 30 0.50activate CDS, no fused silica filter 15 0.25D2 lamp only channel 0.00adjust CDS to RASCAL alignment 30 0.50adjust count rate 15 0.25use CDS 145nm filter

D2 spectrum with full COS resolutionG130M c = 1309 15 0.25G160M c = 1600 15 0.25G140L c = 1230 15 0.25

Configure RASCAL largest aperture 15 0.25adjust count rate 15 0.25use CDS 145nm filter

D2 spectrum with PSA filledG130M c = 1309 15 0.25G160M c = 1600 15 0.25




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Test #800FUV FP-SPLIT Spectra

• Level II FP-SPLITs• SMS operations• Measure offsets between subexposures using one standard FP-SPLIT

exposure for each grating, FUV– G130M central wavelength = 1309– G160M central wavelength = 1600– G140L central wavelength = 1230

• Use CDS lamp-only channel with Pt-Ne lamp• Adjust count rate to obtain > 1000 cts in each subexposure for several

lines in each segment• Use STScI standard wavecal exposure strategy for “auto FP-SPLIT”• Use RASCAL 10m aperture

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• Assess algorithms for combining subexposures– The primary goal is to test the ability to combine the four subexposures

without loosing spectral resolution.

– Measure offsets. Is a constant value adequate, or does the offset vary with grating, segment, pixel or wavelength?

– This is not intended to be a demonstration of the ability of FP-SPLITs to increase the S/N

• Assess auto FP-SPLIT operational procedures– Sequence of wavecal and external target exposures

– Shutter operations

• Derive and apply wavelength scales, assess accuracy– Zero-point shift could be beam centering in aperture

– Look for errors correlated with segment, pixel or wavelength

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Test #800FUV FP-SPLIT Spectra


turn on COS, FUV, PSA 105 1.75turn on RASCAL, 10m aperture 30 0.50activate CDS, no fused silica filter 15 0.25Pt-Ne lamp-only channel 0.00adjust CDS to RASCAL alignment 30 0.50adjust count rate 15 0.25

FUV G130M FPSPLIT + wavecal 30 0.50FUV G160M FPSPLIT + wavecal 30 0.50FUV G140L FPSPLIT + wavecal 30 0.50




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Test #550Transmission of CDS ND filters

• RT operations• Use external CDS Pt-Ne lamp and COS low resolution gratings

to measure attenuation as function of wavelength.• Use RASCAL 100m aperture• Adjust count rate for 10000 cts/segment second for FUV, or

well below rate at which dead-time effects are expected. Count rates with no attenuation must be reliable.

• Use G140L and G230L• Measure each filter in CDS inventory, ND0.5, 1, 2, 3• Done at this point after analysis of test #100. Allows time for

analysis of Tests 200 & 300 before executing tests 600 & 700.

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Test #550Transmission

of CDS ND filters


turn on COS, FUV, PSA 105 1.75turn on RASCAL, 100m aperture 30 0.50activate CDS, no fused silica filter 15 0.25Pt-Ne lamp-only channeladjust CDS to RASCAL alignment 30 0.50adjust count rate 15 0.25use experience from earlier tests

FUV G140L c = 1230ND 0 10 0.17ND0.5 10 0.17ND1 10 0.17ND2 10 0.17ND3 10 0.17ND 0 10 0.17

switch to COS NUV PSA 30 0.50adjust count rate for NUV 15 0.25

NUV G230L c = 3000ND 0 10 0.17ND0.5 10 0.17ND1 10 0.17ND2 10 0.17ND3 10 0.17ND 0 10 0.17




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Test #600Calibration subsystem flat-field lamps

2nd light

• Level I Flat-field Lamp Operation

• SMS operations. Tests #600 and 700 may be combined into one SMS

• Mechanism positions, lamp currents and exposure times are updated after the “1st light” test.

• Use the updated configurations to take exposures according to the nominal strategy for use of the D2 lamps. This may include use of FP-SPLIT subexposures.– FUV Seg A, G130M, 1310 – 1450, either lamp medium current– FUV Seg B, G160M, 1420 – 1580, either lamp low current– NUV use G185M, either lamp high current

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turn on COS, FUV, FCA 105 1.75CDS off & shutter closed

G130M FF#1 medium 15 0.25G160M FF#1 low 15 0.25G130M FF#2 medium 15 0.25G160M FF#2 low 15 0.25

switch to COS NUV FCA 30 0.50

G185M FF#1 high 10 0.17G185M FF#2 high 10 0.17



FUV without startup & shutdown 60 1.00 hoursNUV without startup & shutdown 50 0.83 hours

total 110 1.83 hours

Test #600Calibration subsystem

flat-field lamps 2nd light


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Test #700Calibration subsystem Pt-Ne lamps 2nd

light• Level I and II Wave Cal Lamp Operation

• SMS operations. Tests #600 and 700 may be combined into one SMS

• This is a place-holder for a second look at the cal subsystem Pt-Ne lamps if changes to mechanism positions, aperture position, exposure times or lamp currents were made as a result of the first light tests, and if those changes are significant enough to require confirmation.

• The execution and contents of this test will be contingent on the outcome of test #300, Pt-Ne lamps 1st light.

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turn on COS, FUV, WCA 105 1.75CDS off & shutter closed

G130M line#1 current TBD 10 0.17G160M line#1 current TBD 10 0.17G140L line#1 current TBD 10 0.17

G130M line#2 current TBD 10 0.17G160M line#2 current TBD 10 0.17G140L line#2 current TBD 10 0.17

switch to NUV WCA 30 0.50

G185M pos. lamp & current TBD 10 0.17G185M pos. lamp & current TBD 10 0.17G185M pos. lamp & current TBD 10 0.17G185M pos. lamp & current TBD 10 0.17



G230L-1 lamp & current TBD 10 0.17G230L-2 lamp & current TBD 10 0.17G230L-3 lamp & current TBD 10 0.17

G230L-1 lamp & current TBD 10 0.17G230L-2 lamp & current TBD 10 0.17G230L-3 lamp & current TBD 10 0.17

TA1 lamp & current TBD 10 0.17TA1 lamp & current TBD 10 0.17

TA1-BRT lamp & current TBD 10 0.17TA1-BRT lamp & current TBD 10 0.17




Test #700Calibration subsystem Pt-Ne lamps 2nd light


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Test #850COS Vacuum Functional Test as

Repeatability Monitor• This is a subset of the full VFT. Observations of internal wavecal an flat-field lamps are used to accumulate data from which repeatability can be assessed.• SMS operation• Planned opportunities for COS Repeatability Monitor

– Once near end of “Initial Alignment..in Vacuum”

– End of Thermal Balance at near nominal temperature

– Hot 1, Cold 1, Hot 2, Cold 2 Thermal Vacuum test plateaus

– During Cold 1 to Hot 2 transition

– End of Thermal Vacuum test at near nominal temperature

– Mid-way through Science Calibration phase

– End of Science Calibration phase

– TBD times at GSFC before and after critical tests or environmental exposures

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Test #850COS Vacuum

Functional Test as Repeatability

Monitor


turn on COS, NUV, WCA 40 0.67CDS off & shutter closed

NUV cal lamp component of SYSFUNCG185M c = 1850 Line2 medium 7 0.12G225M c = 2250 Line2 medium 7 0.12G285M c = 2850 Line2 medium 7 0.12G230L c = 3000 FPSPLIT, Line2 medium 13 0.22NUV TA1 Line2 low 6 0.10NUV TA1BRT Line1 low 6 0.10

switch to NUV FCA 10 0.17G185M c = 1850 Flat1 high 10 0.17

FUV cal lamp component of SYSFUNCswitch to FUV, WCA 65 1.08G140L c = 1230 FPSPLIT, Line2 medium 9 0.15G130M c = 1309 Line2 medium 6 0.10G160M c = 1600 Line 2 medium 7 0.12

switch to FUV FCA 10 0.17G160M c = 1600 Seg B Flat1 low 10 0.17G130M c =1309 Seg A Flat2 medium 10 0.17



FUV time, no startup or shutdown 52.00 0.87 hoursNUV time, no startup or shutdown 66 1.10 hours

Totals without startup or shutdown 118 1.97 hours

initial alignment check / calibration in vacuum dennis ebbets with substantial contributions from...

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