NHSC HIFI DP workshop Caltech, 7-9 February 2011 - page 1 Pat
Morris Steve Lord, Adwin Boogert, Colin Borys (NHSC) Carolyn McCoey
(Univ. of Waterloo) Emmanuel Caux, IRAP (ex-CESR) Thanks Frank
Helmich, HIFI PI, and the HIFI Consortium The HIFI Instrument
Status, AOTs, and Calibrations Slide 2 - page 2 Welcome NHSC team
Science Adwin Boogert Herschel DP Training Champions Group Colin
Borys NHSC rep Herschel DP Mgt Group Steve Lord Pat Morris NHSC rep
Herschel DP User Group Applications Joan Xie Annie Hoac Carolyn
McCoey, U. Waterloo Herschel DP Training Champions Group Emmanuel
Caux, IRAP HIFI Co-PI HIFI rep Herschel DP User Group HIFI Users
Group Slide 3 - page 3 Outline Part I: Expectations & Goals,
Preliminaries, Data Access Part II: Instrument Status and Health
Part III: Calibrations Part IV: Cross-Calibrations (HIFI vs APEX,
SPIRE) Part V: AOT Status Slide 4 - page 4 Expectations & Goals
Learn HIPE Become familiar with the GUI concepts and usage, how to
execute pipelines and explore your data Learn where to find
templates data reduction scripts and how to use them... and import
and execute custom scripts Learn how to read/ingest your data in
HIPE Learn how to process HIFI data to Level 2+ products Learn
about resources and support NHSC can provide Processing science in
HIPE with CASSIS (joint session) Sessions will use public data for
demo and practice purposes. Slide 5 - page 5 Preliminaries Do you
have the right version of HIPE installed? Where are the data?
Should I have them already? What if I dont? How do I ensure Im
ready to go? Where are the scripts? What are tutorials? The next
two presentations will answer these questions. We have allowed for
some time to be used for testing your setup (before/during coffee)
Slide 6 - page 6 Data access this week HSA ESA Mission Ops Center
ESAC, Madrid HIFI ICC DB NHSC/HIFI DB You @ NHCS HIPE NHSC/HIFI has
reprocessed data in HIPE 5.1, and provided in local stores Slide 7
- page 7 Data access at t > this week HSA ESA Mission Ops Center
ESAC, Madrid You @ home HIPE The HSA is the only repository of
observations and calibrations that can be accessed by the observing
community. Help from NHSC and HSC always available. Slide 8 - page
8 Part II Instrument health and status Slide 9 - page 9 HIFI Single
Event Upsets An SEU in August 2009 attributed to CR on a sensitive
memory chip in the LO control unit caused premature power-off of
the LOU, killing HIFIs Prime side (DC/DC converter failure) HIFI
runs on its REDUNDANT side since February 2010, with new intensive
fault protection S/W. SEU occurring statistically every 12 days
Recovery now well established and rapid. One full power cycle (last
resort) has been required, when HIFI stopped reacting to commands.
~2 ODs lost to LCU SEUs 5 ODs lost to ICU SEUs but PACS rescheduled
so no observatory time lost. Slide 10 - page 10 LSU OXCO Anomaly
HIFIs 10 MHz signal (for locking LO chains, LSU, WBS and HRS) is
generated by a crystal. Crystal is heated to 100 C for best
performances The heater circuit is not working well. Temperatures
began spiking in June 2010, investigation concluded that the
circuit is reacting to LSU temperature control switching to an
on/off mode. The LSU and HIFI are operating within design
specifications, and the crystal temperature is within the nominal
tolerances so science observations are not affected. Slide 11 -
page 11 Slide 12 - page 12 LSU OXCO scenarios We cannot change
anything in software or by commanding. We have to wait and see what
happens, three scenarios are possible : Situation remains stable
Currently science data are not affected Keep operating HIFI as is
Heater circuit dies, but crystal keeps working Drift of HIFI
frequency expected that needs to be characterized, especially at
the jump (may then stabilize) Dedicated characterization +
observing known lines every OD Heater circuit dies, takes crystal
with it End of HIFI Slide 13 - page 13 WBS-V comb fade WBS-V comb
has a failed component, already discovered in 2007 The WBS-V could
not be removed and repaired. Comb power continued to drop Steep
decay between OD 320 and OD 420, lighter since No remaining
attenuation in subband 4 (2-3 dB in others) Comb line intensity
dropped to < 40 counts, much lower than specs. Possible
reduction of accuracy in determining comb line positions, reduced
frequency calibration accuracy expected S/N still > 400 in
sub-band 4 Slide 14 - page 14 HRS-WBS cross calibration Measure
pair of spectra with WBS and HRS at any input (preferentially from
internal 100 K hot load) Compute mutual correlation as function of
relative shift HRS can be positioned to cover almost the full WBS
scale Some On-Board S/W bugs to use this being worked out. Accuracy
of about 100kHz (best case 30kHz) No issues with WBS-H so far.
Slide 15 - page 15 Reality Check The HIFI team has been working
through so-called Failure Mode Effects and Critical Analysis
(FMECA) since assembly and test phases. A lot of things are related
to problems anticipated at launch Secondary are all the power
supplies, which are supposed to be robust, however, not guaranteed
Tens of items exist that say switch to redundant that option was
required already during PV, thus is no longer available and thus we
operate with numerous possible single point failures The FMECA is
on functional level Hundreds of components can cause a functional
problem. Chance that HIFI survives the remaining mission is not
close to 100% anymore Slide 16 - page 16 Part III Calibrations
Slide 17 - page 17 LO Spurs and Spurious Response Impurity features
in HIFI are manifest as ~25MHz, Gaussian-shaped features in hot,
cold, on, and off data. Both WBS and HRS are affected. Because they
look a lot like astronomical lines, they can fool users. The
repeatable ones are tabulated in PHS (HSpot) and pipeline tables.
In the pipeline, the hot/cold loads are searched in all science
observations, and spurs are flagged. Hot and Cold Loads from an
observation in band 1a Slide 18 - page 18 Spur clean-up at
instrument level Many of the most troublesome impurities (e.g. near
key lines) have been cleaned up, by (time/labor intensive) tests
and changes to multiplier settings and bias voltages. Band 1a spur
eliminated (557 GHz H2O line region) System temperature increased
at upper 1.5 GHz of band Sensitivity in band 1a is better than that
in band 1b for LO frequencies up to 551.9 GHz. V H V Slide 19 -
page 19 Band 5b purification LO-band 5B had several LO spikes at
the same time Result is that the IF consists of several frequency
bands superposed on each other. Calibration of all frequencies
within the IF was unknown Purification efforts took many weeks.
AORs in 5b were released in December 2010. Band 5B was not alone in
impurities but in the diplexer bands the diplexer can moved and the
signal evaluated at each setting to give purest signal more
efficiently (in observing terms). Purification in bands 3b/7b done
this way (Band 5 has no diplexing). Purification is a major triumph
for modeling of the LO chains! Slide 20 - page 20 Sensitivities
Sensitivities are driven mainly by System Temperatures and Aperture
(or beam) Efficiencies. Tsys remains essentially as measured just
before launch --- some small changes at specific frequencies to
mitigate impurities and unstable tunings. Slide 21 - page 21 Beam
Calibrations H/V beam sizes and co-alignment Measured mainly from
Saturn, Uranus, Mars Beam offsets are taken into account in the
HIFI pipeline since 5.0 Slide 22 - page 22 Efficiencies Beam
efficiencies measured on Mars +Overall ~10% better than pre-launch
estimates o Data taken before Nov 2010 should have somewhat better
noise performance (HSpot 5.2 uses updated effciencies). Band 5a/b
are an exception, ~10% lower. Slide 23 - page 23 Error Budget Error
sourceB1/B2B3/B4B5B6/B7 Sideband ratio
