| CAID: MIPS-950 | Title: Scattered Background Monitor | |
| System: MIPS | Principal: mrieke | Deputy: jkeene |
| Objective: | Determine the level of scattered background light within MIPS when the scan mirror is moved to the "dark" position. By executing this measurement repeatedly as the telescope cools, true dark current can be separated from background light scattered into the focal plane. Note that a separate test for checking light scattered from point sources is required and will be executed under another program. |
| Description: | A series of repeated measurements of the signal seen in of the three MIPS detector channels with the scan mirror positioned to place the detector in the dark. This is the first time the test will be executed. Flow: 1) Position scan mirror at 6.25 deg to place 24um array into the dark. 2) Take 10 3-sec exposures using the 24um channel. Use "raw" mode to return all readouts. 3) Position scan mirror at 3.8 deg to put part of 70um array in dark (two positions required) 4) Take 2x10 3-sec exposures using the 70um array. 5) Position scan mirror at -4.5 deg to place 160um array into the dark. 6) Take 10 3-second exposures using the 160um array. |
| Day: 5.9819444444438 | Suggested Order: | ||
| Must be preceded by these activities (list by CAID): CTA-050, MIPS-010R | |||
| Place in Schedule: Can begin after aperture door is opened and basic MIPS functionality is established. | |||
| Priority: Critical | |||
Conditions | |||
| Maximum telescope temperature: | 150 K | ||
| Minimum telescope temperature: | 5.5 K | ||
| Should activity be repeated if focus changes? | No Repeat if focus changes by 0 mm | ||
| Maximum absolute pointing uncertainty: | 600 arcsec (1 sigma radial) | ||
| Maximum precision offset uncertainty: | 600 arcsec (1 sigma radial) | ||
| Observatory configuration: | Pointing at high ecliptic latitude, empty sky | ||
| Go/No Go criteria: | Scan mirror and MIPS array readout must be functional | ||
Duration: 30 minutes
| | Real time downlink:
No | | |||
| Data Volume (uncompressed): 20 Mbits | |||
| List Blocks, AORs, SERs, IERs, or unique sequences required (uplink): Could use the same IER as for measuring dark current | |||
| List Analysis tools required (downlink): | |||
| Estimate of data turn around: 24 hours | |||
| Description: The level of darkness within MIPS will be known and can be fed into the use of the Total Power Mode AOT. The final results will not be known until all the repetitions of the scattered background monitor have been executed. | |||
| Can proceed in parallel with other activity: Yes | |||
| Must outcome be confirmed before next activity: No | |||
| Method of Confirmation: data analysis | |||
| Success criteria: | |||
| Contingency plan: This first execution of the scattered light test is likely to have all detectors saturated if the dark position only reduces the background by a factor of 10. If dark is darker than this, then the 24um detectors might be responsive. | |||
Comments | |||
| References: | |||
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Additional Comments:
Required Conditions: Basic detector and scan mirror operation must be confirmed before executing this program. This template should be executed several times: at least at 150>T>80, 75>T>55, 50>T>30, 25>T>15, 10>T> 5.5, and again at T ~ 5.5. It may be executed every campaign until T ~ 5.5. | |||
| This activity last updated: 10/11/2001 3:33:56 PM | |||