CHAMP+ Efficiency Measurements
Hier müssen noch links hin !!!!Hier müssen noch links hin !!!!Hier müssen noch links hin !!!!Hier müssen noch links hin !!!!Hier müssen noch links hin !!!!Hier müssen noch links hin !!!!Hier müssen noch links hin !!!!Hier müssen noch links hin !!!!
= Abbildung, ganz unten
Date | Source | Θd["] | ηf (λ) | Subarray | ν[GHz] | Θmb["] | ηs(λ) | Notes |
Observing Campaign: July-September 2014 | ||||||||
10.09.2014 | Mars | 6.58 | 0.95 | LFA | 660.4 | 9.1 | 0.43 |
Observations with new closed-cycle calibration unit. Results are consistent with previous LN2 calibrations. |
HFA | 807.1 | 7.7 | 0.32 | |||||
10.07.2014 | Mars | 8.94 | 0.95 | LFA | 691.9 | 8.7 | 0.41 |
Cal Unit out of operation. Calibration performed manually with LN2 paddle. |
HFA | 807.1 | 7.7 | 0.34 | |||||
Observing Campaign: November 2012 | ||||||||
07.11.2012 | Jupiter | 47.4 | 0.95 | LFA | 691.9 | 8.9 | 0.49 | Mars to weak. Because Jupiter is consistent with previous observations, use 2009 efficiencies for compact targets. |
HFA | 807.1 | 7.7 | 0.48 | |||||
Observing Campaign: July 2010 | ||||||||
23.07.2010 | Jupiter | 43.1 | 0.95 | LFA | 691 | 8.9 | 0.48 | LFA efficiencies are 10% on the low side, for all sources |
0.95 | HFA | 809 | 7.7 | 0.48 | to be investigated in September 2010 | |||
19.-25.07. | Mars | 4.85 | 0.95 | LFA | 691 | 0.36 | ||
0.95 | HFA | 809 | 0.36 | |||||
23.07.2010 | Uranus | 3.56 | 0.95 | LFA | 691 | 0.34 | ||
0.95 | HFA | 809 | 0.32 | |||||
Observing Campaign: August 2009 | optics corrected, surface adjusted | |||||||
04.08.2009 | Moon | 1765 | 0.95 | LFA | 691 | 8.9 | 0.82 | close to full moon |
0.95 | HFA | 806 | 7.6 | 0.84 | ||||
04.08.2009 | Jupiter | 47.3 | 0.95 | LFA | 691 | 8.9 | 0.52 | |
0.95 | HFA | 806 | 7.6 | 0.49 | ||||
04.08.2009 | Mars | 5.4 | 0.95 | LFA | 661 | 8.7 | 0.43 | LFA beam is smaller than "nominal" |
0.95 | HFA | 809 | 7.6 | 0.35 | ||||
Observing Campaign: June 2009 | CHAMP+ optics anomaly (5) | |||||||
16.06.2009 | Jupiter | 42.36 | 0.95 | LFA | 661 | 9.3 | 0.46 | dewar position: 97 deg |
0.95 | HFA | 809 | 7.7 | 0.40 | ||||
22.06.2009 | Mars | 4.86 | 0.95 | LFA | 689 | 8.8 | 0.40 | dewar position: 90 deg |
HFA | no data, recommend to use 0.35 | |||||||
Observing Campaign: September 2008 | after telescope surface adjustment | |||||||
14.09.2008 | Moon | 1855 | 0.95 | LFA | 691 | 8.9 | 0.82 | full moon |
0.95 | HFA | 806 | 7.7 | 0.78 | ||||
09.09.2008 | Jupiter | 41.1 | 0.95 | LFA | 658 | 9.4 | 0.48 | |
0.95 | HFA | 815 | 7.7 | 0.45 | ||||
0.95 | HFA | 881 | 7.0 | 0.44 | ||||
14.09.2008 | Uranus | 3.64 | 0.95 | LFA | 691 | 8.9 | 0.38 | |
0.95 | HFA | too weak for cal, use Oct 07 numbers | ||||||
Observing Campaign: July 2008 | prior to tel. adjustment; after subreflector change | |||||||
18.07.2008 | Jupiter | 45.8 | 0.95 | LFA | 661 | 9.3 | 0.45 | |
0.95 | HFA | 809 | 7.7 | 0.43 | ||||
05.07.2008 | Mars | 4.36 | 0.95 | LFA | 691 | 8.9 | 0.28 | |
0.95 | HFA | 806 | 7.7 | 0.30 | ||||
Observing Campaign: October 2007 | calibration with internal cold/losses | |||||||
22.10.2007 | Jupiter | 32.5 | 0.95 | LFA | 661 | 9.3 | 0.45 | |
0.95 | HFA | 809 | 7.7 | 0.42 | ||||
23.10.2007 | Mars | 11.4 | 0.95 | LFA | 691 | 8.9 | 0.38 | |
0.95 | HFA | 806 | 7.7 | 0.35 |
Addendum:
- The CHAMP+ beams are diffraction limited, use ΘFWHP ≈ 1.2 λ/D.
- The forward efficiency ηf (λ) is best estimated (0.95 ± 0.02); so far we have been unable to establish stable skydip analysis for submm wavelength (incl. self-consistent solution for the sky temperature in atm).
- Efficiencies are generally uniform across the arrays (within a few per cent); except for HFA pixels #1 and #2, for which in 09-2008 we derive slightly lower source couplings (ηs(#1) = 0.85 and ηs(#2) = 0.89 times the table figures). This can be supplied by the apexOfflineCalibrator.
- Image gains: for the 2007 measurements, a gain ratio of 0.05 is a good figure. Due to the transport damage to the refurbished cryo-optics, in 2008 sideband suppressions vary with frequency and with pixel position. But generally are better than 10 dB in the IF band center. Currently the calibrator cannot handle IF-variable image gains.
- The June 2009 observations were affected by an anomaly in the warm optics (relaxed mirror fixation). This made the LFA beam toggle on the subreflector depending on the cryostat position. In consequence we have a coupling efficiency that depends on the orientation of the dewar (Fig). Fortunately, because we make use of the 60 deg symmetry of the array, most of the observations are carried out in an angular range that compares with the angle used for typical efficiency measurements. For proper calibration (1) inspect the range of the dewar angles used for your observation and (2) correct with the tools made available, if necessary (contact F. Wyrowski about the procedures). The HFA efficiency was somewhat reduced, but independent of the dewar orientation.