| CAID: MIPS-246 | Title: 70 um and 160um Optimum Bias Setting | |
| System: MIPS | Principal: dmkelly | Deputy: eyoung |
| Objective: | Determine the best detector bias for each MIPS Ge array. |
| Description: | Four performance criteria, (responsivity, dark current, read noise, and stim repeatability) will be checked as a function of bias. A total of five bias settings will be tested at 70um and 160um. This test should also be performed during thermal vac. |
| Day: 51.152777777781 | Suggested Order: I015 | ||
| Must be preceded by these activities (list by CAID): MIPS-247, MIPS-248, MIPS-322, MIPS-324 | |||
| Place in Schedule: Must be prior to instrument characterization tests and after startup tests like the first light test. Since it possibly uses the 70um and 160um photometry modes, it must come after the preliminary verification of the photometry/superresolution AOT. | |||
| Priority: Critical | |||
Conditions | |||
| Maximum telescope temperature: | 6 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: | 0 arcsec (1 sigma radial) | ||
| Maximum precision offset uncertainty: | 0 arcsec (1 sigma radial) | ||
| Observatory configuration: | |||
| Go/No Go criteria: | The telescope needs to be fully cooled and the background needs to be stable so that we can measure the instrument dark current and stability. | ||
Duration: 660 minutes
| | Real time downlink:
No | | |||
| Data Volume (uncompressed): 6212 Mbits | |||
| List Blocks, AORs, SERs, IERs, or unique sequences required (uplink): 70um and 160um dark IERS, 70um and 160um special photometry IERs | |||
| List Analysis tools required (downlink): Truncated version of standard MIPS data reduction pipeline (one that gives stim flash brightnesses as an output product) plus custom-written tools for extracting stim flash brightnesses and assessing stim repeatability. | |||
| Estimate of data turn around: 72 hours | |||
| Description: Run data through pipeline. Use odd stim flashes to calibrate even stim brightnesses and assess stim repeatability. Use stim brightness to assess responsivity, or if using photometry AOTs, calibrate star brightnesses using stim flashes and use star brightness to determine responsivity. Use darks to determine read noise. If measuring darks with stims at the internal dark position, use those data to determine the dark current, otherwise make a best estimate of the dark current from the darks measured with no stim flashes. Combine the information on stim repeatability, responsivity, dark current, and read noise in a manner TBD to determine the optimum Vbias level for each array. | |||
| Can proceed in parallel with other activity: No | |||
| Must outcome be confirmed before next activity: No | |||
| Method of Confirmation: All subsequent data collected with the instrument will give us an idea of whether we chose the right bias values. | |||
| Success criteria: Sufficient quality data is obtained to assess responsivity, noise levels, and stim repeatability as a function of bias for each of the Ge arrays. | |||
| Contingency plan: If this test fails to execute or if it gives ambiguous answers, we will use the data obtained during thermal vac testing as the basis for choosing array biases. As we gain further experience with the arrays, we will assess whether the biases we have chosen are working out well or if some minor adjustments are needed. | |||
Comments | |||
| References: | |||
|
Additional Comments:
| |||
| This activity last updated: 4/18/2002 11:26:07 AM | |||