Atacama Pathfinder EXperiment APEX
LABOCA Calibration
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Home > Instrumentation > LABOCA > LABOCA Calibration > Array parameters

Array parameters December 2007 (16/11-31/12)

By mid-november, we discovered that the mounting structure installed recently in the C-cabin (to be used with CHAMP+ tests or holography) was shadowing a significant fraction (31 channels) of LABOCA's field of view. The structure was removed on November 15th in the afternoon. LABOCA continued to work as expected until the end of December, when we warmed it up at the start of the Bolivian winter.

Main parameter file: laboca-2007-12.rcp

Individual scans

Scan #Date Parameter fileArray plotIndividual channel maps
47507 2007-11-16T07:56 Mars_47507_Laboca.rcp array_47507.pdf beams_47507.pdf
48118 2007-11-19T08:19 Mars_48118_Laboca.rcp array_48118.pdf beams_48118.pdf
48756 2007-11-24T05:27 Mars_48756_Laboca.rcp array_48756.pdf beams_48756.pdf
54019 2007-12-21T05:28 Mars_54019_Laboca.rcp array_54019.pdf beams_54019.pdf
54552 2007-12-24T03:32 Mars_54552_Laboca.rcp array_54552.pdf beams_54552.pdf
54993 2007-12-26T06:03 Mars_54993_Laboca.rcp array_54993.pdf beams_54993.pdf

Notes on individual channels

Channel #Description
101, 103, 106, 110 Strong cross-talk: 101↔106 & 103↔110.
81-91, 92, 93-96, 135, 136, 142, 145, 150, 151, 157-160 Channels located in group 4 / cable M. All active channels pick up signal from channel 92 (cross-talk) in varying intensities, from few-percent level (#47507) to significant. Channel 92 is considered bad.
6, 179, 183, 184, 191, 192, 201, 205, 207, 217, 218, 220, 228, 309 Bad (noisy or insensitive) channels.
241 No proper signal. Picks up signal from channels 248 (strong) and 296 (weak).

channel_flags-2007-12.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
# 5 channels show strong cross-talk
cross = [ 101, 103, 106, 110, 241 ]
# Bad channels (no or very weak astronomical signal)
bad = [ 6, 92, 179, 183, 184, 191, 192, 201, 205, 207, 217, 218, 220, 228, 309 ]
# Remaining bolometers on cable M / group 4 (affected by cross-talk)
cable_M = [ 81, 82, 83, 84, 85, 86, 89, 90, 91, 93, 94, 96, 136, 159, 160 ]