Atacama Pathfinder EXperiment APEX
LABOCA Calibration
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Array parameters June 2008 (27/05-21/06)

LABOCA was cold (Helium temperature) between May 11th and July 2nd. No mechanical work has been performed at the instrument during this period. Thus the channel offsets are not expected to have changed and are averaged from 2 maps in May and 3 maps in June (and are therefore identical for both periods).
For some unknown reason, the bias voltage of amplifier box #3 was too low after May 27th. This led to changing relative channel gains. The bias has been adjusted to its nominal value on June 21st. Thus the channel gains in the rcp files differ between May and June.
Concerning individual channels, the only difference is channel 185, which was bad in May and seems to be ok again around mid June. It is still considered bad in the channel flags macro.

Main parameter file: laboca-2008-06.rcp

Individual scans

Scan #Date Parameter fileArray plotIndividual channel maps
19329 2008-06-01T22:20 Mars_19329_Laboca.rcp array_19329.pdf beams_19329.pdf
22145 2008-06-14T22:41 Mars_22145_Laboca.rcp array_22145.pdf beams_22145.pdf
22335 2008-06-15T18:54 Mars_22335_Laboca.rcp array_22335.pdf beams_22335.pdf

Notes on individual channels

Channel #Description
101, 103, 106, 110 Strong cross-talk: 101↔106 & 103↔110.
81, 82, 83, 84, 85-96, 135, 136, 142, 145, 150, 151, 157-160 Channels located in group 4 / cable M. 82 and 84 are considered bad, the other active channels pick up signal from channel 84 (cross-talk).
6, 180, 184, 204, 220, 228 Bad channels (no astronomical signal or noisy).
201, 205, 207, 218, 309 Insensitive channels.
179 This channel shows very low signal and therefore high S/N.
185 Variable channel. Bad in map 19329, ok in the others. Marked as bad in the channel flags.
241 No proper signal. Picks up signal from channels 248 (strong) and 296 (weak).

channel_flags-2008-05.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 that show strong cross-talk
cross = [ 101, 103, 106, 110, 241 ]
# Bad channels (no astronomical signal)
bad = [ 6, 82, 84, 179, 180, 184, 185, 201, 204, 205, 207, 218, 220, 228, 309 ]
# Remaining bolometers on cable M / group 4 (affected by cross-talk)
cable_M = [ 81, 83, 85, 86, 89, 90, 91, 92, 93, 94, 96, 136, 159, 160 ]