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LABOCA Calibration
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Array parameters April 2009 (15/03-01/05)

During March 2009, LABOCA was removed from the C-cabin and the hexapod support was improved with new leg joints. The support was also improved for the mirror M6 in the C-cabin. After remounting, LABOCA was realigned and cooled down with liquid Helium on March 9th to 11th, with observations starting on Marth 15th.
These mechanical changes required a complete new set of array parameters, which were obtained by observations of several beam maps.

During this observing period, we found out that the pointing accuracy with LABOCA was still not perfect. Thus at the beginning of May the remaining LABOCA mirrors were also equipped with new hexapod joints, which again required new array parameters (2009-05).

Main parameter file: laboca-2009-04.rcp

Individual scans

Scan #Date Parameter fileArray plotIndividual channel maps
7762 2009-03-15T03:14 Saturn_7762_Laboca.rcp array_7762.pdf beams_7762.pdf
7790 2009-03-15T05:12 Saturn_7790_Laboca.rcp array_7790.pdf beams_7790.pdf
9033¹ 2009-03-24T09:07 Jupiter_9033_Laboca.rcp array_9033.pdf beams_9033.pdf
12412¹ 2009-04-05T09:44 Jupiter_12408_Laboca.rcp array_12408.pdf beams_12408.pdf
15009 2009-04-22T12:30 Mars_15009_Laboca.rcp array_15009.pdf beams_15009.pdf
15993 2009-04-24T23:51 Saturn_15993_Laboca.rcp array_15993.pdf beams_15993.pdf
17098 2009-04-27T23:42 Saturn_17098_Laboca.rcp array_117098.pdf beams_17098.pdf
 ¹ Scan 9033 and 12408 (Jupiter) are only used to identify bad channels. Because of Jupiter's angular size, they are not considered in producing the averaged array parameter file.

Notes on individual channels

Channel #Description
101, 103, 106, 110, 205, 218 Strong cross-talk: 101↔106, 103↔110, and 205↔218.
81-96, 135, 136, 142, 145, 150, 151, 157-160 Channels located in group 4 / cable M. No signal and/or cross-talk (on a 20-30% level), depending on the date. We consider them bad.
6, 160, 201 Bad channels not showing any astronomical signal or very low signal levels.
207, 228, 241 No proper signal. Pick up signal from other channels at varying levels.
179, 180, 183, 184, 185, 217, 220, 309 Channels which are sometimes considered bad. Check your data.
257 Noisy, but will be weighted down during reduction.

channel_flags-2009-04.boa:

# 25 channels not connected to any bolometer
not_connected = [ 29,  33,  35,  40,  64,  66, 124, 135, 142, 144, 146, 151, 158,
                 189, 193, 195, 200, 224, 226, 284, 295, 302, 304, 306, 311 ]
# 20 channels with 1MOhm resistor
resistor = [  15,  16,  87,  88,  95, 139, 143, 145, 149, 150, 157, 178,
             181, 186, 187, 188, 190, 255, 310, 317 ]
# 2 channels sealed with an absorber
blind = [ 4, 163 ]
sealed = blind
# Channels showing strong cross-talk
cross = [ 101, 103, 106, 110, 205, 218 ]
# Bad channels (no/low signal)
bad = [ 6, 160, 201, 207, 228, 241 ]
# Remaining channels in group 4 / cable M:
cable_M = [ 81, 82, 83, 84, 85, 86, 89, 90, 91, 92, 93, 94, 96, 136, 159 ]
# Channels which are variable:
bad_maybe = [ 179, 180, 183, 184, 185, 217, 220, 309 ]
# Cable M channels are considered bad:
bad = bad + cable_M