Subject: weeks 7-8 campaign structures



Hi,

The following discussion covers the proposed sequence of MIPS tasks
for weeks 7-8, campaigns H,I,J,K.  I also include a discussion of
the standard calibration sequence to be used in SV and throughout 
the mission.  Dean and Jocelyn have the most schedule-sensitive
tasks, so they ought to review my logic in putting together these
sequences.  Anyone else who feels like reading 400 lines of text
can do the same.  Alberto usually takes responsibility for implementing
these sequences, but I think the job now falls on Debbie.  Please
forward this to the appropriate person if that is not the case.

Doug
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MIPS CAMPAIGN H                                            time since 
Start-up activities, Si and Ge           MIPS-905    35     Ge anneal
Routine 24um flux standard               MIPS-920    11        24
Scattered background monitor             MIPS-950    30        35
Routine 24um flux standard               MIPS-920    11        65
160um First light and Ph/SR AOT val.(Prel)MIPS-324   18        76
160um Stim response                      MIPS-248    10        94
Routine 24um flux standard               MIPS-920    11       104
IOC Darks, 160um                         MIPS-912     9       115
IOC Darks, 24um                          MIPS-910    15       124
Routine 24um flux standard               MIPS-920    11       139
IOC Darks, 70um                          MIPS-911    30       150
160um Voffset adjustment test            MIPS-127     5       180
Routine 24um flux standard               MIPS-920    11       185
70um Spectral leak check                 MIPS-241    50       196

Ge Anneal and recovery                   MIPS-930    12       246
160um On-board data processing algorithmsMIPS-112    15        10
Calibration stars against different bkgdsMIPS-921    60        25
160um IC - routine, Phot AOR             MIPS-919    21        85
70um IC - routine, Phot AOR              MIPS-918    21       106
Periodic IRU Calibration updates          PCS-055    36       127
Periodic PCRS/STA alignment filter updatesPCS-105    12       163
70um WF Focal plane survey (coarse)      MIPS-132   126       175

24um Flat - routine, Phot AOR            MIPS-917    10       301
24um Flat - routine, Phot AOR            MIPS-917    10       311
24um Scan AOT validation (Preliminary)   MIPS-326    18       321
24um Frame table update sanity check     MIPS-960     8       339
Shutdown activities, Ge and Si           MIPS-992    19       347

Comments:  The driving factor at the start of this campaign is the
multiple runs of MIPS-920.  These 5 repeats are designed to study
the stability of the 24um array response over the first three
hours after instrument power-up.  To accomplish this, we need to
run MIPS-920 right after MIPS-905 and then again at semi-regular
intervals over the next several hours.  The other big influencing factor
is the need to schedule 227m of 70um, 78m of 160um activities, and
90m of tasks covering all 3 arrays (MIPS-950 and MIPS-921) within 
the windows of good Ge operations following the anneals.  The Ge
anneals occur fairly early during the startup activities, further
restricting the available Ge test time.  The result of all this is
a 3-part campaign structure, with a mix of 24um responsivity checks
and Ge tasks during the first part, with the rest of the Ge tasks and 
the FPS in the second part, and with the remainder of the 24um tasks
in the third part.
In ground testing, the 24um responsivity changes were greatest during
the first hour, so I tried to schedule short activities in between the 
early runs of MIPS-920 to get good sampling.  I also wanted to minimize 
pointing overheads by linking together tasks that require identical 
pointing and by emphasizing observations near the CVZ.  I put the 
scattered background monitor test first, in great part to provide
consistency with earlier campaigns.  Also, this is the last execution
of this task and the only one at nominal temperatures, so it is 
important that we get good Ge measurements.  I put the 160um first 
light and stim response tasks next because I think it is essential
that we get those tasks done early, before the 160um responsivity has 
changed much.  I am mainly guarding against stim saturation.  If we
want to be overly cautious, we could schedule this task first after 
MIPS-930, when only 10m of cosmic ray damage has occurred.  I think
the better approach for the start of IOC is to select a stim brightness 
that avoids saturation problems.  The 160um and 24um darks were lumped 
together to avoid pointing overheads, with the 160um measurement coming 
first for cosmic ray reasons.  I put the 160um Voffset test right after 
the 70um darks since the pointing is the same.  I put the 70um spectral 
leak check last during this first part of the campaign.  There will be 
4h of radiation damage on the array by the end of this task, which is
large but not excessive.  We plan to look at bright sources and to look 
in detail at the PSF.  Saturation during this test would be a disaster, 
so care is needed in the source selection.  
In the second part of the campaign, I open with the on-board data 
processing task.  It is performed while observing a standard star, which 
is why I paired it with MIPS-921.  These tasks are placed ahead of the
illumination correction measurements to put the IC measurements the same
amount of time after the anneal as they will be during standard startup
activities.  This places MIPS-921 early after the anneal, when the
stim/source calibration at 70um is potentially not so good.  The guard
against this is to put the 70um observations from MIPS-921 towards the
end of that task.  The IC measurements are made together since they are 
measured far from the CVZ.  
This puts the start of the 70um FPS at 2h after the anneal and the end
of this task at 4h after the anneal.  These times are again large but
not excessive -- we should expect the responsivity to be up about 
1.5-2x during this test.  Saturation would mess up the centroiding, so 
we need to be careful in the source selection.  With the FPS starting
6h after the start of the campaign, we can expect good temperature
stability for the telescope and electronics, which improves the pointing
stability.  As for the PCS tasks, the IRU calibration has to happen every
24h and the PCRS calibration has to take place every 8h.  There is only
+/- 1h of tolerance on these times.  Working from the current timeline,
that puts these tasks where I list them above, right before the FPS.
That would delay the start of the FPS by 48m, which is starting to get
a bit uncomfortable.  It would be a lot nicer if we could defer the PCS
commands until after the FPS.
There is no particular logic behind the ordering of the tasks in the 
third part of the campaign other than putting the two 24um flat 
observations together to reduce pointing overheads.  
This campaign involves the first 160um operations and the last scattered
light measurement.  It will be difficult to do much at 160um if the
telescope temperature is above 7K.  The scattered light test should
possibly be deferred if the telescope is not yet close to its final
temperature.
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MIPS CAMPAIGN I                                            
Periodic PCRS/STA alignment filter updatesPCS-105    12    time since
Start-up activities, Si and Ge           MIPS-905    35    70um anneal
70um and 160um Optimum bias setting      MIPS-246   660        24
Periodic PCRS/STA alignment filter updatesPCS-105    12        70
IOC Darks, 70um                          MIPS-911    30        82
70um IC - routine, Phot AOR              MIPS-918    21       112
70um IC - routine, Scan AOR              MIPS-915    13       133
70um NF Illumination correction          MIPS-313    19       146
70um WF Focal plane survey (coarse)      MIPS-132   126       165

Ge Anneal and recovery                   MIPS-930    12       291
24um Optimum operating temperature       MIPS-345    90        10
70um NF Focal plane survey (coarse)      MIPS-137   130       100
SED Slit location and orientation        MIPS-139   108       230

Periodic PCRS/STA alignment filter updatesPCS-105    12       338
Periodic IRU Calibration updates          PCS-055    36       350
IOC Darks, 24um                          MIPS-910    15       386
24um Flat - routine, Phot AOR            MIPS-917    10       401
24um Flat - routine, Scan AOR            MIPS-914    13       411
Shutdown activities, Ge and Si           MIPS-992    19

Comments: The Ge bias optimization is the dominant task in this
campaign.  I made a mistake when I wrote it by not performing a 
thermal anneal at the start of the task.  This is corrected by 
scheduling this task first in the campaign, after the thermal 
anneals in MIPS-905.  The nominal place for the first PCS-105
execution is after MIPS-905, but I prefer to see it before we
start so that it does not interfere with our timeline.  The
second execution of PCS-105 has to happen right after MIPS-246.
There is a 70um thermal anneal 70m before the end of MIPS-246
and a 160um anneal 10m before the end of the task.  With about
9h of Ge activities in the rest of the campaign, it is essential 
that we take advantage of these anneals and defer all 24um tasks 
until the end of the campaign.  Unfortunately the 24um optimum 
temperature test is primarily a 160um dark measurement test, so 
it has to come early after an anneal.  I start with the 70um 
darks because we were pointing at dark sky for MIPS-246.  I placed 
the three ICs next, grouped to reduce pointing overheads.  The 
WF FPS comes next.  This is over 13h since the start of the 
campaign, so operating temperatures should be stabilized.  
An anneal is needed next, followed by the 24um optimum operating
temperature test.  I put this test right after an anneal to obtain
the best possible information on the 160um dark levels and to avoid
having to perform an extra thermal anneal.  The 70um NF FPS task 
comes next.  I am eager to complete this task before too much
radiation damage has accumulated.  The SED slit location is the 
last of the Ge tasks.  This test runs from 4-5.5h after the thermal 
anneal.  I think we can get away with this even if the 70um array
proves to be rather sensitive to radiation damage because the 
analysis will involve averaging over a large number of pixels.  
That makes us relatively immune to spiking events, which is not 
the case for the FPS.  This brings us to 9h after the previous PCRS 
calibration so the IRU and PCRS tasks have to come next.  I listed 
the PCRS task first since it is supposed to happen on an 8h schedule.
For the Si tasks, the flats should be paired.  The darks were listed 
first because both the darks and the SED task are likely to be 
performed near the CVZ, however the PCS tasks involve pointing 
elsewhere in the sky, so we could just as well perform the flats 
first before the darks.
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MIPS CAMPAIGN J                                            Time since
Start-up activities, Si and Ge           MIPS-905    35     Ge anneal
IOC Darks, 160um                         MIPS-912    15        24
IOC Darks, 70um                          MIPS-911    30        39
IOC Darks, 24um                          MIPS-910    15        69
24um Flat - routine, Scan AOR            MIPS-914    13        84
24um Flat - routine, Phot AOR            MIPS-917    10        97
160um IC - routine, Scan AOR             MIPS-916    13       107
160um IC - routine, Phot AOR             MIPS-919    21       120
70um IC - routine, Scan AOR              MIPS-915    13       141
70um IC - routine, Phot AOR              MIPS-918    21       154
70um NF Illumination correction          MIPS-313    19       165
Periodic PCRS/STA alignment filter updatesPCS-105    12       184

Ge Anneal and recovery                   MIPS-930    12       196
160um Flux standards                     MIPS-924    20        10
IER to set 160um stim level to 0x2E                   0        30
160um Stim and star calibration          MIPS-601     7        30
IER to set 160um stim level to 0x33                   0        37
160um Stim and star calibration          MIPS-601     7        37
IER to set 160um stim level to 0x3C                   0        44
160um Stim and star calibration          MIPS-601     7        44
IER to reset 160um stim level to 0x37                 0        51
70um Flux standards                      MIPS-922    12        51
IER to set 70um stim level to 0x22                    0        63
70um Stim and star calibration           MIPS-600    10        63
IER to set 70um stim level to 0x2A                    0        73
70um Stim and star calibration           MIPS-600    10        73
IER to set 70um stim level to 0x34                    0        83
70um Stim and star calibration           MIPS-600    10        83
IER to reset 70um stim level to 0x2F                  0        93
Routine 24um Flux standard               MIPS-920    11        93
70um NF Focal plane survey (coarse)      MIPS-137   130       104

Ge Anneal and recovery                   MIPS-930    12       234
160um Array location and orientation     MIPS-234   152        10
SED Slit location and orientation        MIPS-139   108       162
70um WF Frame table update sanity check  MIPS-961     8       270
Periodic PCRS/STA alignment filter updatesPCS-105    12       278
Periodic IRU Calibration updates          PCS-055    36       290

Ge Anneal and recovery                   MIPS-930    12       326
160um Flux standards                     MIPS-924    20        10
IER to set 160um stim level to 0x2E                   0        30
160um Stim and star calibration          MIPS-601     7        30
IER to set 160um stim level to 0x33                   0        37
160um Stim and star calibration          MIPS-601     7        37
IER to set 160um stim level to 0x3C                   0        44
160um Stim and star calibration          MIPS-601     7        44
IER to reset 160um stim level to 0x37                 0        51
70um Flux standards                      MIPS-922    12        51
IER to set 70um stim level to 0x22                    0        63
70um Stim and star calibration           MIPS-600    10        63
IER to set 70um stim level to 0x2A                    0        73
70um Stim and star calibration           MIPS-600    10        73
IER to set 70um stim level to 0x34                    0        83
70um Stim and star calibration           MIPS-600    10        83
IER to reset 70um stim level to 0x2F                  0        93
Shutdown activities, Ge and Si           MIPS-992    19        93

Comments: There are two primary activities in this campaign.  One is
a very thorough investigation of calibration using standard activities,
the other is a set of focal plane surveys.  For the calibration 
tasks, I used the standard startup sequence as much as possible.
I put the Phot versions of the 24um flat, 70um IC, and 160um IC in
sequence right after the Scan versions of each task.  This maximizes
efficiency and provides the best comparison between the two techniques.
The extra time required is not that large, so the timing of the 
calibration activities is not altered much compared to the standard startup.
After the first anneal, I broke from the usual startup sequence by 
running the set of MIPS-601 tasks immediately after MIPS-924.  I 
jumped from there to MIPS-922, postponing MIPS-920 until later.  This
puts MIPS-922 at very nearly the usual timing after the thermal anneal.
Both of these Ge calibration sequences are completed before much cosmic 
ray damage has accumulated.  The next task is the 24um flux standard.  
This is very different timing from the usual startup sequence, but that 
should not be an issue at 24um this long after the initial powerup.  The 
70um NF FPS was placed next, partly because the pointing is likely to be
similar to that of the flux standards but mostly because it fit nicely
into the available time.  This task is run between 2-4h after the thermal
anneal, which is very good timing.  The task starts about 5h after startup,
which ought to be sufficient to reach temperature stability.  A thermal 
anneal prepares the 160um array for MIPS-234.  This task is long enough 
that it really needed to be run right after a thermal anneal.  The SED 
slit location task will have similar pointing and will work well between 
3-4.5h after the anneal.  The frame table update comes next and was 
placed here to avoid interfering with any of the other calibration 
activities.  The campaign ends with a repeat of the Ge flux standard 
calibration activities, starting with a thermal anneal and following 
the same sequence as was used earlier.  This cycle of calibration tasks 
starts about 7.5h after the start of the first set, so we have a decent 
timeline for looking for changes.
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MIPS CAMPAIGN K                                            Time since
Start-up activities, Si and Ge           MIPS-905    35     Ge anneal
Startup Transients, 24um and Ge Arrays   MIPS-226    60        24
24um Flat - routine, Scan AOR            MIPS-914    13        84
24um Flat - routine, Phot AOR            MIPS-917    10        97
160um IC - routine, Scan AOR             MIPS-916    13       107
160um IC - routine, Phot AOR             MIPS-919    21       120
70um IC - routine, Scan AOR              MIPS-915    13       141
70um IC - routine, Phot AOR              MIPS-918    21       154
70um NF Illumination correction          MIPS-313    19       175
SED Mode Wavelength Calibration          MIPS-145    40       194

Ge Anneal and recovery                   MIPS-930    12       234
Flux Calibration 1                       MIPS-350    83        10
160um Spectral Leak Check                MIPS-242    50        93
Periodic PCRS/STA alignment filter updatesPCS-105    12       143
SED Slit Illumination Function           MIPS-299    20       155
SED Skeleton AOT Validation              MIPS-300    42       175
70um and 160um Thermal Anneal Behavior   MIPS-160   360         0
Periodic PCRS/STA alignment filter updatesPCS-105    12       360
Periodic IRU Calibration updates          PCS-055    36       372

Ge Anneal and recovery                   MIPS-930    12       408
IOC Darks, 160um                         MIPS-912    15        10
160um Array Location and Orientation     MIPS-234   152        25
IOC Darks, 70um                          MIPS-911    30       177
IOC Darks, 24um                          MIPS-910    15       207
Shutdown activities, Ge and Si           MIPS-992    19       222

Comments:  A big part of this campaign is checking the stability and
behavior of the Ge arrays following startup and following a thermal
anneal.  MIPS-226 has to come right away to address this need, and
MIPS-160 has to come much later in the campaign, when startup transients 
are not a factor.  None of the other tasks impose major scheduling
constraints.  I changed the usual startup sequence because of the 1-hour
hit caused by MIPS-226.  By displacing the dark tasks, I maintain 
the same schedule for the flats and ICs as was used in campaign J.  
There is no reason to perform an anneal yet, so I placed one of the 
SED mode tests next.  I chose the wavelength calibration task because 
the PN or HII region in question might be in a similar part of the 
sky to the IC fields, whereas the other SED tasks are probably in 
the CVZ.  I placed an anneal next rather than the other two SED tasks
to even out the time in each anneal cycle.  After the anneal, the 
first task is the flux calibration task MIPS-350.  This task is a 
superset of the usual flux standard tasks MIPS-920,922,924, which 
are performed right after the anneal in the standard startup sequence.  
To match the usual sequence and to assure best array performance, 
it would be best if the MIPS-350 observations were performed in the 
sequence 160um first, then 24um and 70um.  The 160um spectral leak 
check comes next.  It is a 160um task and so needs to be run within 
the first two hours after an anneal.  The other two SED tasks finish 
up this anneal sequence.  This brings us about 7h into the campaign, 
which is sufficiently long for us to be able to place MIPS-160 next.  
A lot of the trouble in scheduling this campaign comes from trying 
to fit in the PCRS/IRU calibrations, with the 6h duration MIPS-160 
being the biggest problem.  By placing MIPS-160 here, we can get 
the PCS tasks out of the way before the next thermal anneal.  The 
160um darks come first after the anneal, just as they do at the 
start of a normal campaign.  The 160um FPS has to come next since 
it runs 2.5h and needs to be completed within the first 3h after 
an anneal.  It is placed well after the start of the campaign, so
there should be very good temperature stability.  The other two 
darks finish off the campaign.
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Standard MIPS CAMPAIGN Calibration Activities         Time since
Start-up activities, Si and Ge      MIPS-905    35  Ge anneal - 10m   R70  R160
IOC Darks, 160um                    MIPS-912    15        14         1.06  1.40
IOC Darks, 70um                     MIPS-911    30        29         1.12  1.80
IOC Darks, 24um                     MIPS-910    15        59         1.23  2.53
24um Flat - routine, Scan AOR       MIPS-914    13        74         1.29  2.86
160um IC - routine, Scan AOR        MIPS-916    13        87         1.33  3.13
70um IC - routine, Scan AOR         MIPS-915    13       100         1.38  3.39
70um NF Illumination correction     MIPS-313    19       113         1.42  3.63

Ge Anneal and recovery              MIPS-930    12       132
160um Flux standards                MIPS-924    20         0         1.00  1.00
Routine 24um Flux standard          MIPS-920    11        20         1.08  1.56
24um Linearity                                  30        31         1.13  1.85
70um Flux standards                 MIPS-922    12        61         1.24  2.57

Comments: Our usual Ge anneal activity includes 10m of settling time
after the completion of the anneals.  For purposes of this discussion,
I assume that the responsivity at that time has a value of 1.0 and
that it increases as R(t) = R0 + 7R0[1-exp(-t/Tau)], where Tau=240m at
160um and as R(t) = R0 + 2R0[1-exp(-t/Tau)], where Tau=480m at 70um.
This is not a great description of the responsivity behavior (it fit
very well to the UC Davis 160um data with a time constant of 60m, but
the energy deposition and hit rate were each about 2-3x too high there;
at 70um only about half of the response change comes from cosmic rays,
and the detector relaxation time constant and the cosmic ray time
constants are probably different from each other).
There is 10m of settling time after the end of the Vrst calibration in
the startup activities.  Ge darks can be a little squirrely depending
on what was observed before them, but in this case we should have been
pointing at fairly low brightness sky for the previous 10m, which is
probably ideal for settling the detectors.  When do we point to the
low brightness sky?  I am assuming that it will be before the end of
MIPS-905, but I really don't know.  The darks should be done in
sequence to reduce pointing overheads and to minimize latency effects.
Cosmic ray effects are minimized by doing the 160um darks first,
followed by the 70um and 24um darks.  By measuring the darks this soon
after the anneal, we get a better measure of the zero-point dark
current and are less affected by stray light.
In standard MIPS operations, we measure point sources and stim flashes
in the Ge detector quick response regime, while sky backgrounds and
flatfields/illumination corrections are measured in the slow response
regime.  Chad Engelbracht did an analysis of Ge data taken with a
modest background and with regular stim flashes.  He found that the
stim flashes did a poor job of tracking the responsivity of the
background for a short time after a thermal anneal, but after about
15m at 160um and an hour at 70um the stim flashes were quite effective
at calibrating the background.  Based on this result, it appears
beneficial to wait at least an hour and preferably longer after a
thermal anneal before collecting our 70um and 160um IC data.  The
worry here is that the shape of the measured IC will change during
the first hour after an anneal due to pixel-to-pixel differences in
the settling time.  The IC measured after an hour should be fairly
stable and should be good for correcting both point sources and
backgrounds.  Most of our science data will be taken in this "settled"
regime, so it is beneficial to measuring the ICs in this same regime.
To accomplish these goals, it is best to delay the IC measurements by
measuring the 24um flats first.  The 160um settling time is quick, so
the 160um IC comes next.  The 70um ICs are saved for last.
The flux standards come last.  I injected an anneal here since otherwise
the 160um responsivity would be 4.0 and the 70um responsivity 1.55 during
the standard star measurements.  Measuring the standards right after an
anneal gives us a good zero-point calibration of the stims and responsivity.
By placing the 24um standard star measurement this late into the startup
calibrations, it is nearly 3h after the instrument startup.  Ground-based
tests suggest a drop in 24um responsivity by 1% during the first hour of
operations followed by recovery over the next two hours.  This test would
occur when the responsivity is at very close to its final value.  The stray
light levels and dark current should be low enough during the 24um darks
that a 1% drop in responsivity should be difficult to measure.  Since the
drop in responsivity was an array-wide effect with little pixel-to-pixel
scatter, it should have no effect on the 24um flats.
For the flux calibrators, there are two important issues.  The first is
the calibration repeatability of the stim flashes after an anneal, which
Chad found to be good immediately after an anneal at 160um and good after
about 10m at 70um.  The other factor is the stability of the stim/source
ratio, which has a settling time akin to the stim/background ratio for
any source not equal in brightness to the stim.  Neither of these factors
precludes running the 160um flux standards first, and that has the
advantage of completing the observations before the responsivity has
changed much.  The 70um stim/source ratio will not be settled yet, so the
two 24um tests are run next.  The 70um flux standards are measured 71m
after the anneal, which is long enough to give good stability.
I am not sure what the 24um linearity test entails but it seems possible
that we will replace it by including RAW measurements in one of our other
24um tasks.

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