MIPS_205a Ge Ga Throughput


IOC-MIPS_205a     10560C,10700C            
Title:   Determination of MIPS Radiometric Throughput at 70 and 160um              
                   
Objective:   Measure the fluxes of known celestial objects to calibrate the absolute throughput at 70 and 160um.              
                 
Description:                  
including flow / state diagram                  
      For each module and mode in MIPS, a celestial standard will be observed.            
      At 70 microns a nominal sensitivity of 100:1 will be achieved.            
      160um at least 10:1 will be achieved. The observed fluxes will be compared to            
      the modelled throughput of MIPS and will be used to update subsequent            
      estimates of sensitivity and integration times required .            
      See attached page for listing of events            
                   
Place in Schedule:                  
(relative to water shed events)                  
                   
      CTA and instrument at nominal operational temperature (below).            
                   
Required Conditions:                  
      Telescope must be at 5.5K            
      Location of MIPS apertures must be completed.            
      Basic instrument comanding and functionality must have been confirmed.            
      At least one of the candidate stars (alpha Tau,alpha Aur, alpha Hya, alpha Boo, gamma Dra for            
      70 and 160um) must be observable.            
                   
Resources:                  
                   
  duration (best estimate)         2 hrs      
  real time downlink (Y / N)         No      
  special post event actions (Y / N)         No      
  Generates ~1500 DCEs depending on overscan distance                
                   
Outcome:                  
  description         Revised throughput numbers      
  can proceed in parallel with other activity         No, dedicated observing.      
  must outcome be confirmed before next event / test /activity         Outcome must be confirmed before tests of ultimate sensitivity can      
            be executed.      
  method of confirmation (sensor TLM, data analysis, etc.)         Data analysis      
  estimate of data turn around if required for confirmation         48 hrs      
                   
Unique or included in planned AOT?                  
      Planned AOTs but with non-standard pipeline processing as calibration data            
      will not yet be available            
                   
Contingency Plan:                  
"What if..."     If throughput is radically different than pre-launch estimates, further analysis and            
      tests to pin point the nature of the problem will be required (eg., are other instruments            
      affected similarly, are backgrounds as expected and so on).            
IOC Critical     Y            
References:                  
                   
Template last updated:     7-Sep-99            
      M. Rieke            
                   
Events:                  
                   
  I. Throughput in Scan Map mode                
                   
  Make scan maps at each scan rate (slow,medium,fast) such that the star              
    traverses each array. Repeat fast scan 4x to get enough integration at 160um.              
    Use the scan map AOT.              
                   
  II. Throughput in Photometry mode                
                   
    Place star on each array (70um,160um) in turn. Take data in a 12 position              
    dither pattern at 70um using the coarse scale and exposing for a total of 30 seconds at each position              
    Take data in an 8 position dither at 160um and 60 seconds total exposure              
    All patterns should be repeated using both 3 and 10 second exposure times              
    Use the photometry/superreolution AOT.              
                   
  III. Throughput in Superresolution Mode                
                   
    Switch 70um module to fine plate scale. Take data in a 12-position dither pattern              
    with a total integration time of ~100 secs per position. Repeat using each of the base integration              
    times of 3 and 10 sec.              
    Use the photometry/superresolution AOT.              
                   
  IV. Throughput in SED Mode                
                   
    Place star near one end of the SED slit. Take a series of exposures totalling              
    150 secs at each of five positions along the slit. Repeat for each of the basic              
    integration times (3 and 10 secs).              
                   
                   


Last Updated on 10/7/99
By Marcia Rieke
Email: mrieke@as.arizona.edu