Peter Shawhan, Andy Lundgren, Nutsinee Kijbunchoo

We did a first -- and successful! -- test of the "detchar" or "safety" hardware injections shortly after 6:00 PDT this morning, at the time recommended by Jeff (work permit 5262).

The detchar injections are a sequence of loud sine-gaussians at a range of frequencies, primarily intended to check for couplings from the GW strain channel to auxiliary channels.  (See https://dcc.ligo.org/LIGO-G1500713 .)  For now, at least, we are using a set of 14 frequencies logarithmically spaced from 30 Hz to 2000 Hz, each injected at 3 different amplitudes to try to get target SNR values, spaced 5 seconds apart.  Here is the full list with times relative to the start time of the injection:
Matlab> GenerateSGSequence('H1','H1_ASD_at_1117710916.txt');
__time__   __freq__   __SNR__    __AMP__
    0.50       30.0      25.0    2.22e-20
    5.50       41.4      25.0    7.54e-21
   10.50       57.2      25.0    2.86e-21
   15.50       79.1      25.0    1.72e-21
   20.50      109.2      25.0    1.52e-21
   25.50      150.9      25.0     1.7e-21
   30.50      208.4      25.0    1.97e-21
   35.50      287.9      25.0    2.92e-21
   40.50      397.7      25.0    3.73e-21
   45.50      549.3      25.0    5.42e-21
   50.50      758.8      25.0    6.95e-21
   55.50     1048.2      25.0     1.1e-20
   60.50     1447.9      25.0    1.71e-20
   65.50     2000.0      25.0    2.68e-20
   70.50       30.0      50.0    4.44e-20
   75.50       41.4      50.0    1.51e-20
   80.50       57.2      50.0    5.71e-21
   85.50       79.1      50.0    3.44e-21
   90.50      109.2      50.0    3.03e-21
   95.50      150.9      50.0    3.41e-21
  100.50      208.4      50.0    3.94e-21
  105.50      287.9      50.0    5.85e-21
  110.50      397.7      50.0    7.47e-21
  115.50      549.3      50.0    1.08e-20
  120.50      758.8      50.0    1.39e-20
  125.50     1048.2      50.0     2.2e-20
  130.50     1447.9      50.0    3.41e-20
  135.50     2000.0      30.0    3.22e-20
  140.50       30.0     100.0    8.88e-20
  145.50       41.4     100.0    3.02e-20
  150.50       57.2     100.0    1.14e-20
  155.50       79.1     100.0    6.87e-21
  160.50      109.2     100.0    6.06e-21
  165.50      150.9     100.0    6.81e-21
  170.50      208.4     100.0    7.87e-21
  175.50      287.9     100.0    1.17e-20
  180.50      397.7     100.0    1.49e-20
  185.50      549.3     100.0    2.17e-20
  190.50      758.8     100.0    2.78e-20
  195.50     1048.2     100.0    4.41e-20
  200.50     1447.9      75.0    5.12e-20
  205.50     2000.0      30.0    3.22e-20
The file, on h1hwinj, is /data/scirun/O1/HardwareInjection/Details/config/Burst/Waveform/detchar_1117890580_3_H1.txt .

With H1 running in good low-noise mode, Nutsinee switched the intent bit to 'commissioning' and we first injected the sequence starting at 1117890580 with an overall scale factor of 0.25 -- so the target SNRs/amplitudes are a factor of 4 smaller than in the table above.  Nutsinee didn't see anything obvious appearing in the live spectrum initially, but Andy looked at Omicron output afterward and say that it had picked up at least some of the louder signals.

We then injected the sequence again starting at 1117891250, this time with an overall scale factor of 1.0 .  Nutsinee saw the signals clearly peak up in the live spectrogram, and Andy's quick check with Omicron showed many signals found with large SNR.  The interferometer appeared to handle the injections fine, staying in lock.  Afterward (and also in between the two injections), Nutsinee set the intent bit back to 'science'.

Note: In the future, we expect detchar safety injections such as these to be marked with the DetChar bit in the CAL-INJ_ODC bitmask, but for the test today we treated it as a burst injection -- it will be marked in ODC (and GDS-CALIB_STATE) as a burst injection, and should produce ODC-INJECTION_BURST segments in the DQ segment database.