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

Array parameters May 2008 (12/05-26/05)

LABOCA had been warmed up to room temperature to investigate the sensitivity problems we had at the beginning of May. It was cooled down again on May 11th and stayed cold until the beginning of July.
After May 27th, the bias voltage of amplifier box #3 was lower than the nominal value. This had some effect on the relative gain values of channels 161 - 240. Thus separate rcp files have been created for these periods, with the channel offsets being an average from 5 maps from May and June, and the gains being different.

Main parameter file: laboca-2008-05.rcp

Individual scans

Scan #Date Parameter fileArray plotIndividual channel maps
17067 2008-05-21T22:56 Mars_17067_Laboca.rcp array_17067.pdf beams_17067.pdf
17533 2008-05-23T18:21 Mars_17533_Laboca.rcp array_17533.pdf beams_17533.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, 185, 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-2008-05.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 ]