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LABOCA Calibration
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Home > Instrumentation > LABOCA > LABOCA Calibration > Array parameters

Array parameters November 2009 (25/10-09/12)

LABOCA was warm during most of October. We started to cool it down on 23rd, it was ready to be used on the 25th, and was used the same day. Last observing day with LABOCA was the 8th of December; it was warmed up for the altiplanic winter shutdown afterward.

On October 27th, the mirror M6 in LABOCA's optical path was replaced by a polarizer module, and the old hot load calibration paddle by a filter wheel. Until October 29th, additional work was performed in the optical path of the instrument.

Main parameter file: laboca-2009-11.rcp

Individual scans

Scan #Date Parameter fileArray plotIndividual channel maps
74998 2009-10-27T08:59 Mars_74998_Laboca.rcp array_74998.pdf beams_74998.pdf
75178 2009-10-28T04:04 Uranus_75178_Laboca.rcp array_75178.pdf beams_75178.pdf
78769 2009-11-08T08:49 Mars_78769_Laboca.rcp array_78769.pdf beams_78769.pdf
81483 2009-11-20T08:01 Mars_81483_Laboca.rcp array_81483.pdf beams_81483.pdf
81899 2009-11-21T07:46 Mars_81899_Laboca.rcp array_81899.pdf beams_81899.pdf

Notes on individual channels

Note: Channels which are terminated with a resistor are not listed in the following table anymore.

Channel #Description
101, 103, 106, 110 Strong cross-talk: 101↔106 and 103↔110.
81, 82, 83, 84, 85, 86, 89, 90, 91, 92, 93, 94, 96, 136, 159, 160 Channels located in group 4 / cable M. Most channels show cross-talk (about 20% level) with channel 92, sometimes also with 90 and 94, or 86, or 93, and are probably usable. Channel 82 doesn't show signal, and is considered bad. Channels 84, 86, 90, 92, 93, and 94 are bad part of the time only. Channel 85 sometimes shows excess noise.
177, 179, 180, 182, 183, 184, 185, 191, 192, 201, 202, 203, 205, 207, 217, 218, 220 Channels located in group 7 / cable A. These channels show problems for a while already. They mostly don't show astronomical signal and are considered bad. Channels 183, 192, 202, 203, and 218 are variable; they sometimes show signal (with excess noise, though). Channel 191 sometimes is ok, except some cross-talk (20% level) with channel 203. Channel 217 sometimes show the same signal as 205.
6, 228, 309 Bad channels, not showing any astronomical signal or very low signal levels, unconnected to groups 4 or 7 above.
222, 257 Variable channels, which sometime do not show any astronomical signal, unconnected to groups 4 or 7 above.
241 No proper signal. Picks up signal from channels 248 (strong) and 296 (weak).

channel_flags-2009-11.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, 241 ]
# Bad channels (no/low signal)
bad = [  6,  82, 177, 179, 180, 182, 184, 185, 201, 205, 207, 217, 220, 228, 309 ]
# Variable channels (sometimes bad, sometimes not)
bad_maybe = [ 84,  86,  90,  92,  93,  94, 183, 191, 192, 202, 203, 218, 222, 257 ]
# remaining channels on Cable M. Cross-talk on a 20% level.
cable_M = [  81,  83,  85,  89,  91,  96, 136, 159, 160 ]