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LABOCA Calibration
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Home > Instrumentation > LABOCA > LABOCA Calibration > Array parameters

Array parameters May 2009 (06/05-27/05)

At the beginning of May, during technical time, the remaining mirrors in the optical path of LABOCA were equipped with new hexapod joints, in order to make the pointing more reliable and to remove any evelation hysteresis effect. The mirrors were re-installed and aligned on May 4th to 6th.
These mechanical changes led to a change of channel offsets of up to 12″ in the lower part of the array. Thus a new set of array parameters was obtained. We do not expect the channel gains to have changed (only the offsets), thus you may obtain both files and average the gains from 2009-04 and 2009-05, to obtain a better S/N.

After this observing period, LABOCA was warmed up to ambient temperature at the end of May.

Main parameter file: laboca-2009-05.rcp

Individual scans

Scan #Date Parameter fileArray plotIndividual channel maps
19425 2009-05-07T00:13 Saturn_19425_Laboca.rcp array_19425.pdf beams_19425.pdf
19750 2009-05-08T00:26 Saturn_19750_Laboca.rcp array_19750.pdf beams_19750.pdf
24660 2009-05-22T00:09 Saturn_24660_Laboca.rcp array_24660.pdf beams_24660.pdf
25882 2009-05-27T00:33 Saturn_25882_Laboca.rcp array_25882.pdf beams_25882.pdf

Notes on individual channels

Channel #Description
101, 103, 106, 110 Strong cross-talk: 101↔106 and 103↔110.
81-85, 86, 87-96, 135, 136, 142, 145, 150, 151, 157-160 Channels located in group 4 / cable M. Unless they are terminated with a resistor anyway, they all show low signal levels and/or cross-talk in-between, depending on the date.
6, 82, 90, 180, 201, 205, 207, 217, 228 Bad channels not showing any astronomical signal or very low signal levels.
179, 185, 191, 192, 202 Variable channels (sometimes bad, sometimes not). Check your data.
241 No proper signal. Picks up signal from channels 248 (strong) and 296 (weak).

channel_flags-2009-05.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 showing strong cross-talk
cross = [ 101, 103, 106, 110, 241 ]
# Bad channels (no/low signal)
bad = [  6,  82,  90, 180, 201, 205, 207, 217, 228 ]
# Variable channels
bad_maybe = [ 179, 185, 191, 192, 202 ]
# remaining channels on Cable M. Bad most of the time, sometimes only cross-talk
cable_M = [  81,  83,  84,  85,  86,  89,  91,  92,  93,  94,  96, 136, 159, 160 ]
# Cable M should be considered bad:
bad = bad + cable_M