Seven Pixel K-band Focal Plane Array Commissioning

We present summaries of initial commissioning tests of the KFPA 7 pixel tests in March and April 2010. These tests accomplished the following goals: confirmation of proper hardware operation, hardware configuration, software configuration, software control, gain calibration, mapping scan organization and data pipeline calibration processes. This page is organized in inverse time order, with the latest results at the top of the page and preceding steps following. The data are organized into 17 test/observing sessions, each with GBT project name TFPA_ and session numbers (ie TKFPA_01 to TKFPA_17). Major milestones in inverse order:

17: Imaging for Pipeline: 2010 April 29 Orion KL, TMC-1

orionKl7BeamExponential.gif
Smoothed Orion KL continuum image

Observations configured for larger scale images, to test pipeline processing. Had some setup issues during these tests, which reduced available time to make large field images.

  • Orion Daisy Map, 7 Beams on NH3 1-1 and 2-2, beam 1 NH3 4-4; Good, but short duration
    • On/Off Orion, Scans 18,19
    • Daisy 10 minutes, Scan 20
    • On/Off Orion, Scans 21,22
  • Orion DecLatMap; Scans not properly centered on target; Data OK, but not optimum shape
    • On/Off Orion, Scans 23,24
    • Partial Map, Scans 25 to 32
  • TMC-1 Galactic Map, Beams 1,2,3,4 on HC5N line, Beams 1,2,3,4 on HC7N; excellent data
    • On/Off TMC-1, Scans 44,45
    • Galactic Map, Scans 50 to 65
    • On/Off Tmc-1, Scans 66,67
  • Orion Square map, 7 Beams on NH3 1-1 and 2-2, beam 1 NH3 4-4; Good data, region undersampled
    • On/Off Orion, Scans 73, 74
    • RaLongMap, Scans 75 to 90
    • On/Off Orion,
orion1-122.png
Spectrum of Orion A in NH3 1-1 and 2-2 lines,
produced from a 10 minute Daisy pattern map of the region (Scan 20).
The left image is 2-2 line, the center image is the continuum image map and
right image is 1-1 emission.

16: Mapping and Calibration: 2010 April 19

Ran tests of nodding spectra with all beams. Seemed OK. Ran some maps of TMC, Orion and M33, which looked reasonable.
  • Moon Daisy scan at low elevation; 7 Beams NH3 1-1 and 2-2
    • On/Off Moon, Scans 23,24
    • Daisy on Moon, Scan 25; 10 Minute duration
    • On/Off Moon Scans 26,27
  • Tmc Spectra, miss-configured Scans 33-38
  • Tmc-1 Map, NH3 1-1 and 2-2 Data look good. Strip is longer perpendicular to source structure. Frequency switched configuration.
    • On/Off Tmc, Scans 39,40
    • DecLatMap, Scans 41 to 61
    • On/Off Tmc, Scans 62, 63
  • Tmc-1 Map
    • On/Off Tmc, Scans 69,70
    • DecLatMap, Scans 71 to 91
    • On/Off Tmc, Scans 92, 93
  • Moon Daisy scan at higher elevation; 7 Beams NH3 1-1 and 2-2
    • On/Off Moon, Scans 94, 95
    • Daisy Scan 96; Duration 10 Minutes
    • On/Off Moon, Scans 97, 98
  • Tests of sub-reflector nod on 3C48, scans 104-109
  • Tests of nod with all beams on 3C48, scans 110 to 117
  • Test of external galaxy mapping on M33 (not much signal)
    • On/Off M33, Scans 118,119
    • Map of M33, Scans 120 to 147
    • On/Off M33, Scans 148,149
  • Orion Daisy Map
    • On/Off Orion, Scans 159, 160
    • Daisy map, Scan 162; Map duration only 5 minutes
    • On/Off Orion Scans 163, 164
  • Initial tests of baseline stability, on M33, 800 MHz bandwidth, only 4 beams, Scans 165 to 172

tmcHC7N.png tmcNH3.png
TMC HC7N image with overlaid spectral band TMC NH3 1-1 image with same overlaid spectral band at right

tmcNH3-1-1spec.png
idlToSdfits output plot of the NH3 1-1 and 2-2 line observations for beam 1

15: Spectral band scan during maintenance: 2010 April 16

Sequence of spectra taken with 50 MHz bandwidth, during GBT Maintenance. scans 16 to 69 have good data. All data taken while GBT at access.

All Beams Summary.

  • The data were analyzed using IDL program rt_idl tkfpa15.pro, provided by Glen Langston.
  • tkfpa_15_Comm_Spurious_IV.pdf Summary Table of spurious.
  • A relatively large spurious (40 in counts) is detected in Banks C samplers # 2, beam 3 R. (The spur at 22438.5 MHz is also in beams 3L,2R, 1L, and 1R at lower levels)
  • Spurious from LO1A - LO1B generated in the TYPE I IDM are introduced into beams 1,2,3 and 4 via the multiplexer.
    • Tunning LO1B to 3/5 LO1A positions the spur on the edge of the 1.8 GHz bandwidth.
    • The small spurious may be a result of the intermodulation products from the out of band spur.
  • tkfpa_15_spur.ps: Image of the spurious for beams 1R,1L,2R,2L,3R,3L,4R,and 4L. This is raw spectrometer scan 65 data plotted with a GLISH program.
  • tkfpa_15_567LR.ps: Image of the spurious for beams 5R,6R,6L,7R,and 7L. This is raw spectrometer scan 65 data plotted with a GLISH program. (Note: spectrum is flipped).
  • However, Bank D sampler 1,3 did not contain the spurious and is a copy of beam 1L.and 1R, respectively.
  • This spurious is introduced before the IDM, since the spectrum is flipped for Type II downconverters versus Type I downconverters.
  • The results are inconclusive, since the spur appears in some beams with type II downconverters but not others. At any rate these are small compared to the 3x2 product(~24000 counts) of the TYPE I downconverters.
  • Bank A sampler 2: beam 2 L; Bank C sampler 0 and 2: 3 L, 3 R; Bank A sampler 0 and 2: 4 L and R all had small spurious at the same frequencies.

14: Spectral band scan during maintenance: 2010 April 13

Sequence of spectra taken with 50 MHz bandwidth, during GBT Maintenance. Scans 102 - 397 cover frequency range 18097 to 24619 MHz

All Beams Summary.
  • The origin or cause of some these spurious are unknown.
  • The data were analyzed using IDL program rt_idl tkfpa14.pro, provided by Glen Langston.
  • tkfpa_14_Comm_Spurious_II.pdf:Table of spurious.
  • tkfpa_14_scan298.ps: GLISH program plot of raw scan 298. It is clean where this same sky frequency contains a large spurious in tkfpa_15 scan 65.

Beam 5L,6R, 6L, 7R, and 7L spectrometer plots for a spurious when Fsky = 22.009917.

  • Spurious frequency equation at second IF for IDM type I: 2 x L01A - 3 x LO1B;
  • For LO1A = 28.809917/2 GHz, and LO1B = 8.9 GHz, the spurious appears is at frequency 2.109917 GHz.

  • In these plots the sky frequency is centered at 25 GHz, thus the spurious appear at 34.917 MHz.

13: Gain Calibration and mappingt tests: 2010 April 8

Observations of the Galactic Center source Sgr B2, known for complex interstellar chemistry.

  • Galactic coordinate map of Sgr B2
    • On/Off Sgr B2, Scans 11,12
    • Galactic map, Scans 13 to 38
    • On/Off Sgr B2, Scans 39,40
  • Pointing and Nod and calibration tests, Scans 45 to 63, on Sgr B2 and Saturn
  • Galactic Mapping Scan, offset from Sgr B2 + 6 arcminutes
    • On/Off Sgr B2, Scans 69,70
    • Galactic map, Scans 71 to 91
    • On/Off Sgr B2, Scans 92,93
  • Galactic Mapping Scan, offset from Sgr B2 - 6 arcminutes
    • On/Off Sgr B2, Scans 99,100
    • Galactic map, Scans 101 to 121
    • On/Off Sgr B2, Scans 122,123
  • Moon Daisy Map, short duration, 5 minutes
    • On/Off Moon, Scans 129,130
    • Daisy Map, Scan 131
  • Tests of different combinations of beams, Nodding towards 3C48, scans 137 to 144
  • Mapping test map towards M33. Small angular region and short duration
    • On/Off M33, Scans 145,146
    • Map of M33, Scans 147 to 157
    • On/Off M33, Scans 158,159
  • Mapping test map towards M33. Small angular region and short duration
    • On/Off M33, Scans 165,166
    • Map of M33, Scans 167 to 177
    • On/Off M33, Scans 178,179

12: Mapping Scans, archive data is missing IF fits files: 2010 April 2

Data look pretty good, but difficult to calibrate and image, due to missing IF fits files in archive data. Observations were all taken in the Seven Beam + 1 mode, observing NH3 1-1 and 2-2 with all beams and NH3 4-4 with beam 1

  • Daisy Map of Sgr B2
    • On/Off Sgr B2, Scans 21,22
    • Daisy map, Scan 23. Only 5 minute duration
    • On/Off Sgr B2, Scans 24, 25
  • RaLongMap of Sgr B2
    • Maps scans of Sgr B2, Scans 26 to 51 (use scans 24,25 for reference)
    • On/Off Sgr B2, Scans 52,53
  • W3-OH map
    • On/Off W3-OH scans, 64,65
    • RaLongMap of W3-OH, scans 66,91
    • On/Off of W3-OH, Scans 92,93

11: Pointing and Gain calibration explorations: 2010 March 28

Exploring software fits file generation and recording of the observing configuration. The archive data are missing the IF Fits files, making calibration difficult.

  • Point and focus scans with different configurations, Scans 1:39
  • RaLongMap of TMC-1
    • On/Off TMC-1, Scans 40,41
    • One Scan map, Scan 42
  • RF spur scan of the band, while telescope was at access, scans 59 to 93

10: Maintenance day check of Astrid configuration scripts: 2010 March 25

9: No data obtained

8: Peak and focus tests of software: 2010 March 22

7: Configuration tests of software: 2010 March 16

6: Configuration tests of software: 2010 March 12

5: Pre-commissioning Configuration tests of software: 2010 February 18

4: Pre-commissioning Configuration tests of software: 2010 February 16

3: Pipeline test of beam offset calculation: 2010 January 28

Very quick observation of 3C123 to make a map big enough to confirm beam offset model for source position. Did not make a large enough map to do a useful test. These observations used the Old GBT K-band Receiver.
  • Small map of 3C123
    • Nod observation of 3C123, Scans 11,12
    • Small square map of 3C123, Scans 17 to 27

2: Maintenance day tests of Astrid Script: 2010 January 26

1: Maintenance day tests of Astrid Script: 2009 December 9

-- GlenLangston - 2010-05-06

Topic attachments
I Attachment Action Size Date WhoSorted ascending Comment
TKFPA_01.txttxt TKFPA_01.txt manage 4 K 2010-04-13 - 16:28 GlenLangston Test obs summary
TKFPA_02.txttxt TKFPA_02.txt manage 434 bytes 2010-04-13 - 16:28 GlenLangston Test obs summary
TKFPA_03.txttxt TKFPA_03.txt manage 1 K 2010-04-13 - 16:28 GlenLangston Test obs summary
TKFPA_04.txttxt TKFPA_04.txt manage 1 K 2010-04-13 - 16:29 GlenLangston Test obs summary
TKFPA_05.txttxt TKFPA_05.txt manage 984 bytes 2010-04-13 - 16:29 GlenLangston Test obs summary
TKFPA_06.txttxt TKFPA_06.txt manage 1 K 2010-04-13 - 16:29 GlenLangston Test obs summary
TKFPA_07.txttxt TKFPA_07.txt manage 2 K 2010-04-13 - 16:30 GlenLangston Test obs summary
TKFPA_08.txttxt TKFPA_08.txt manage 2 K 2010-04-13 - 16:30 GlenLangston Test obs summary
TKFPA_10.txttxt TKFPA_10.txt manage 960 bytes 2010-04-13 - 16:30 GlenLangston Test obs summary
TKFPA_11.txttxt TKFPA_11.txt manage 8 K 2010-04-13 - 16:30 GlenLangston Test obs summary
TKFPA_12.txttxt TKFPA_12.txt manage 3 K 2010-04-13 - 16:31 GlenLangston Test obs summary
TKFPA_13.txttxt TKFPA_13.txt manage 7 K 2010-04-13 - 16:31 GlenLangston Test obs summary
TKFPA_14.txttxt TKFPA_14.txt manage 19 K 2010-04-13 - 16:31 GlenLangston Test obs summary
TKFPA_15.txttxt TKFPA_15.txt manage 5 K 2010-06-02 - 13:32 GlenLangston Observing summary
TKFPA_16.txttxt TKFPA_16.txt manage 9 K 2010-06-02 - 13:32 GlenLangston Observing summary
TKFPA_17.txttxt TKFPA_17.txt manage 4 K 2010-06-02 - 13:31 GlenLangston Observing summary
orionKl7BeamExponential.gifgif orionKl7BeamExponential.gif manage 33 K 2010-05-06 - 15:16 GlenLangston Smoothed Orion KL continuum image
tmcHC7N.pngpng tmcHC7N.png manage 48 K 2010-04-21 - 12:27 GlenLangston HC7N map and spectrum
tmcNH3-1-1spec.pngpng tmcNH3-1-1spec.png manage 86 K 2010-04-21 - 12:29 GlenLangston idlToSdfits NH3 1-1 and 2-2
tmcNH3.pngpng tmcNH3.png manage 39 K 2010-04-21 - 12:28 GlenLangston tmcHC7N
B5L_22spur.psps B5L_22spur.ps manage 29 K 2010-06-01 - 13:56 StevenWhite  
B6L_spur.psps B6L_spur.ps manage 29 K 2010-06-01 - 14:23 StevenWhite  
B6R_22Gspur.psps B6R_22Gspur.ps manage 29 K 2010-06-01 - 14:23 StevenWhite  
B7L_22Gspur.psps B7L_22Gspur.ps manage 29 K 2010-06-01 - 14:24 StevenWhite  
B7R_22Gspur.psps B7R_22Gspur.ps manage 30 K 2010-06-01 - 14:24 StevenWhite  
moonKfpa10Apr18.jpgjpg moonKfpa10Apr18.jpg manage 222 K 2010-04-20 - 09:40 StevenWhite  
tkfpa_14_Comm_Spurious.pdfpdf tkfpa_14_Comm_Spurious.pdf manage 406 K 2010-06-25 - 15:52 StevenWhite  
tkfpa_14_Comm_Spurious_II.pdfpdf tkfpa_14_Comm_Spurious_II.pdf manage 407 K 2010-07-15 - 14:54 StevenWhite  
tkfpa_14_scan298.psps tkfpa_14_scan298.ps manage 36 K 2010-06-24 - 14:01 StevenWhite  
tkfpa_15_567LR.psps tkfpa_15_567LR.ps manage 44 K 2010-07-19 - 15:27 StevenWhite  
tkfpa_15_Comm_Spurious_IV.pdfpdf tkfpa_15_Comm_Spurious_IV.pdf manage 407 K 2010-07-19 - 16:23 StevenWhite  
tkfpa_15_spur.psps tkfpa_15_spur.ps manage 43 K 2010-06-24 - 14:03 StevenWhite  
Topic revision: r18 - 2010-08-26, StevenWhite
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