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

Array parameters November 2007 (18/10-15/11)

Around mid-October, a special mounting structure for CHAMP+ tests and the holography receiver was installed in the Cassegrain cabin. By mid-november, we discovered that this structure was shadowing a significant fraction (32 channels) on the eastern edge of LABOCA's field of view. The structure was removed on November 15th in the afternoon.
No manual work was done on LABOCA itself, thus we don't expect the channel parameters to have changed afterwards, except probably some channels at the eastern edge, close to the shadowed area.

Main parameter file: laboca-2007-11.rcp

Individual scans

Scan #Date Parameter fileArray plotIndividual channel maps
46274 2007-11-10T08:46 Mars_46274_Laboca.rcp array_46274.pdf beams_46274.pdf
47083 2007-11-14T09:12 Mars_47083_Laboca.rcp array_47083.pdf beams_47083.pdf
47307 2007-11-15T09:13 Mars_47307_Laboca.rcp array_47307.pdf beams_47307.pdf

Notes on individual channels

Channel #Description
101, 103, 106, 110 Strong cross-talk: 101↔106 & 103↔110.
241 No proper signal. Picks up signal from channels 248 (strong) and 296 (weak).
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 (which is considered bad). This causes very light cross-talk, probably insignificant for data reduction.
6, 179, 184, 191, 192, 201, 205, 207, 217, 218, 220, 228, 309 Bad (noisy or insensitive) channels.
18, 28, 171, 172, 174, 177, 180, 185, 196, 213, 219, 221, 225, 227, 232, 248, 252, 254, 256, 259, 265, 273, 275, 278, 280, 283, 294, 299, 305, 314, 316, 320 32 channels shadowed by a mounting structure in the C-cabin.

channel_flags-2007-11.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
# 5 channels show strong cross-talk
cross = [ 101, 103, 106, 110, 241 ]
# Bad channels (no or very weak astronomical signal)
bad = [ 6, 92, 179, 184, 191, 192, 201, 205, 207, 217, 218, 220, 228, 309 ]
# Remaining bolometers on cable M / group 4
cable_M = [ 81, 82, 83, 84, 85, 86, 89, 90, 91, 93, 94, 96, 136, 159, 160 ]
# Channels shadowed by the mounting structure in the C-cabin
shadowed = [  18,  28, 171, 172, 174, 177, 180, 185, 196, 213, 219, 221,
             225, 227, 232, 248, 252, 254, 256, 259, 265, 273, 275, 278,
             280, 283, 294, 299, 305, 314, 316, 320 ]