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LABOCA Calibration
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Array parameters April 2010 (28/03-30/06)

LABOCA was warm during the altiplanic winter in January and February. During the second half of February, some repair work was done on a support structure within the cryostat. Afterwards, it was cooled down and kept cold a good fraction of March.

In order to save liquid Helium, we warmed up LABOCA in the second half of March. No further mechanical work was performed then. It was finally cooled down again on March 27th to be ready to start with science observations in April. Then it was used almost without interruption until June 30th.

During March we obtained several beammaps. Since no significant changes were observed between those and the ones obtained in April, we averaged them all together to produce the rcp file you find here.

During the period covered here, two events should be noted: First, some liquid Nitrogen entered the Helium tank on 14th April, and supposedly has caused some contamination. Second, on 10th of June we heated up LABOCA to 100K in order to remove this contamination (since we noted a deterioration of sensitivity). Although these events have no effect on the channel parameters, they may have effected the bad channels (see below).

Main parameter file: laboca-2010-04.rcp

Individual scans

Scan #Date Parameter fileArray plotIndividual channel maps
8330 2010-03-03T01:20 Mars_8330_Laboca.rcp array_8330.pdf beams_8330.pdf
8354 2010-03-03T02:53 Mars_8354_Laboca.rcp array_8354.pdf beams_8354.pdf
8365 2010-03-03T03:31 Mars_8365_Laboca.rcp array_8365.pdf beams_8365.pdf
8642 2010-03-04T02:57 Mars_8642_Laboca.rcp array_8642.pdf beams_8642.pdf
8643 2010-03-04T03:20 Mars_8643_Laboca.rcp array_8643.pdf beams_8643.pdf
8644 2010-03-04T03:42 Mars_8644_Laboca.rcp array_8644.pdf beams_8644.pdf
12565 2010-03-28T03:42 Mars_12565_Laboca.rcp array_12565.pdf beams_12565.pdf
16527 2010-04-12T01:44 Mars_16527_Laboca.rcp array_16527.pdf beams_16527.pdf
16815 2010-04-13T01:37 Mars_16815_Laboca.rcp array_16815.pdf beams_16815.pdf
21075 2010-04-28T00:36 Mars_21075_Laboca.rcp array_21075.pdf beams_21075.pdf
37552 2010-06-20T09:00 Uranus_37552_Laboca.rcp array_37552.pdf beams_37552.pdf
38096 2010-06-22T08:18 Uranus_38096_Laboca.rcp array_38096.pdf beams_38096.pdf

Notes on individual channels

Note: Channels which are terminated with a resistor are not listed in the following table anymore.

Channel #Description
101, 103, 106, 110 Strong cross-talk: 101↔106 and 103↔110.
81, 82, 83, 84, 85, 86, 89, 90, 91, 92, 93, 94, 96, 136, 159, 160 Channels located in group 4 / cable M. Most channels show cross-talk (about 30% level) with channel 136, and are probably usable, at least for very compact sources. Channels 82, 86, 94, and 136 are considered bad. Note that some variability is observed for these channels. They were all bad in scan 38096 (June). Check your data to verify that they are usable.
177, 179, 180, 182, 183, 184, 185, 191, 192, 201, 202, 203, 205, 207, 217, 218, 220 Channels located in group 7 / cable A. These channels show problems for a while already. They mostly don't show astronomical signal and are considered bad.
6, 208, 228, 294, 309 Bad channels, not showing any astronomical signal or very low signal levels, unconnected to groups 4 or 7 above.
114, 213, 257 Variable channels. 114 and 213 were bad only in the June beammaps, 257 after mid-April. Check your data.
241 No proper signal. Picks up signal from channels 248 (strong) and 296 (weak).

channel_flags-2010-04.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,  86,  94, 136, 177, 179, 180, 182, 183, 184, 185, 191, 192,
       201, 202, 203, 205, 207, 208, 217, 218, 220, 228, 294, 309 ]
# Channels which are bad at least part of the time
bad_maybe = [ 114, 213, 257 ]
# remaining channels on Cable M. Bad or cross-talk on a 30% level.
cable_M = [  81,  83,  84,  85,  89,  90,  91,  92,  93,  96, 159, 160 ]
# Uncomment the following to be on the safe side:
#bad = bad + bad_maybe + cable_M