Atacama Pathfinder EXperiment APEX
LABOCA Calibration
MPIfR Bonn   ESO   Onsala Space Observatory
  APEX TWIKI CONTACT SEARCH HELP NEWS DISCLAIMER

Home > Instrumentation > LABOCA > LABOCA Calibration > Array parameters

Array parameters December 2008 (17/11-31/12)

LABOCA was warm between the 2nd and 17th of November. Then it was cooled down in order to be available as back-up instrument for weather which is insufficient for SABOCA. (We performed commissioning and science verification observations with SABOCA at that time.)
After the science observing period ended and the Bolivian Winter arrived. we warmed up LABOCA on 31st of December 2008.

Only two beam maps were observed during this period, and we noted a siginificant change in the numbers of bad channels. Thus we advice you to verify the channel response (and the channels to be flagged during data reduction) on your target data or maps of strong calibrators observed during your project. In addition, a consistent change in Elevation offsets has been noted compared to the October maps, maybe because of a mechanical movement of LABOCA during the SABOCA dismount and reinstallation in November.

Main parameter file: laboca-2008-12.rcp

Individual scans

Scan #Date Parameter fileArray plotIndividual channel maps
63925 2008-11-19T00:20 Uranus_63925_Laboca.rcp array_63925.pdf beams_63925.pdf
73666 2008-12-25T23:46 Uranus_73666_Laboca.rcp array_73666.pdf beams_73666.pdf

Notes on individual channels

Channel #Description
103, 110 Strong cross-talk: 103↔110.
6, 82, 83, 85, 86, 98, 101, 106, 159, 160, 179, 184, 191, 201, 204, 205, 207, 218, 220, 228, 257, 309 Bad channels, not showing any astronomical signal or excess noise.
92, 183, 202, 294 Channels which are bad only in scan 63925
18, 49, 84, 90, 94, 96, 97, 99, 102, 105, 107, 108, 123, 125, 236, 265 Channels which are bad only in scan 73666
241 No proper signal. Picks up signal from channels 248 (strong) and 296 (weak).

channel_flags-2008-12.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
# channels showing strong cross-talk
cross = [ 103, 110, 241 ]
# Bad channels (no signal or noisy)
bad = [  6,  82,  83,  85,  86,  98, 101, 106, 159, 160, 179, 184, 191,
       201, 204, 205, 207, 218, 220, 228, 257, 309 ]
# Suspicious channels (sometimes noisy, sometimes not)
bad_maybe_nov = [ 92, 183, 202, 294 ]
bad_maybe_dec = [ 18,  49,  84,  90,  94,  96,  97,  99, 102, 105, 107, 108,
                 123, 125, 236, 265 ]