Atacama Pathfinder EXperiment APEX
LABOCA Calibration
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Array parameters July 2008 (22/06-02/07)

LABOCA was cold (Helium temperature) between May 11th and July 2nd. No mechanical work has been performed at the instrument. The bias voltage of amplifier box #3, which was too low after May 27th, has been adjusted to its nominal value on June 21st. Thus all channel parameters (offsets and gains) were back to the numbers from May 2008.
The only difference is channel 185, which did not seem to show problems after mid June. Thus it was no longer considered bad. Otherwise the channel flags are also identical to May 2008.

Main parameter file: laboca-2008-05.rcp

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.
241 No proper signal. Picks up signal from channels 248 (strong) and 296 (weak).

channel_flags-2008-07.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, 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 ]