LIGO-G I S5 calibration status Michael Landry LIGO Hanford Observatory for the LSC Calibration Committee LSC/Virgo Meeting May 22, 2007 Cascina, Italy

LIGO-G I Landry - L/V meeting, 22 May Talk overview Frequency-domain calibration h(f) »V3 calibration and review, some gory details »Factors  (t),  (t) »Validation work for GRB Time-domain calibration h(t) Photon calibrator High-frequency calibration

LIGO-G I Landry - L/V meeting, 22 May Calibration committee »S. Giampanis, E. Goetz, G. González, M. Hewitson, S. Hild, E. Hirose, P. Kalmus, M. Landry, E. Messaritaki, B. O’Reilly, R. Savage, X. Siemens, M. Sung »Virgo: B. Lieunard, F. Marion, B. Mours, L. Rolland Calibration review committees »Frequency domain: S. Fairhurst, K. Kawabe, V. Mandic, J. Zweizig »Time domain : S. Fairhurst, K. Kawabe, V. Mandic, B. O’Reilly, M. Sung, S. Waldman »High frequency : K. Kawabe, M. Rahkmanov, R. Savage, D. Sigg

LIGO-G I Landry - L/V meeting, 22 May Frequency-domain calibration We model the DARM loop in MATLAB Compare this model to measurements of the open- loop gain, electronics in the Actuation and Sensing chains and DC value of the Actuation. Optical and loop gain are tracked by time-dependent coefficients which are generated on minute or second time scales. These coefficients are used to propagate measurements at t 0 to other times.

LIGO-G I Landry - L/V meeting, 22 May A(f) D D (f)  (t)C D0 (f) DARM_ERR  + s=h(t)+n(t) DARM_CTRL s res =(L x -L y )/L  + DARM_CTRL_EXC Measure Open-Loop Gain at a reference time t 0 G 0 (f) = A(f)C D0 (f)D D (f) h(f,t) = R DERR (f,t)DERR(f,t) Darm loop

LIGO-G I Landry - L/V meeting, 22 May Frequency-domain status Since last L/V meeting: »V3 calibration released (Nov 4 05 – Jan 22 07) »V3 currently being reviewed » Changes to a machine’s state are reflected in the calibration yielding epochs L1 »3 epochs due to servo changes »Roughly 3, 1/2 and 15 months in duration, respectively H1 »4 epochs due to servo and DARM gain changes »3, 4, 4, and 7 months in duration H2 »3 epochs due to servo changes »3, 8, 6 months in duration

LIGO-G I Landry - L/V meeting, 22 May Open loop gain model/ measurement comparison H1 H2 L1

LIGO-G I Landry - L/V meeting, 22 May H1 ITM comparison Results of MICH sweeps, corrected for pendulum H1 – Nov H1 – Dec 8 06

LIGO-G I Landry - L/V meeting, 22 May DC cal histories H1 L1

LIGO-G I Landry - L/V meeting, 22 May Factors at reference time :  (t),  (t) L1 – epoch 3

LIGO-G I Landry - L/V meeting, 22 May Calibration for GRB GRB event ostensibly in M31 on Feb 1, 2007 : H1 and H2 locked in science mode Validate V3 calibration for Feb 1, 2007 »Made V4 calibrations: checked against V3 »Checked Feb 1 IFO configurations against that of V3 reference time »Autocalibration check : check V3 against quasi-independent autocalibrator procedure Conclude V3 calibration acceptable for GRB Technical doc T W, “Validation of the S5 V3 LHO calibrations for GRB070201” written

LIGO-G I Landry - L/V meeting, 22 May h(t) Description at » S4 review complete Production of V3 h(t) underway »h(t) in LIGO naturally follows on from frequency domain model »Necessary filters created from h(f) V3 DARM model »Lengthy process (~ month) to reprocess S5 data with updated V3 calibration and produce h(t) : data are on tape h(t) now employed by all search groups

LIGO-G I Landry - L/V meeting, 22 May Photon calibrator Intensity modulated radiation pressure excites ETM, approximately sinusoidally, at a chosen frequency. Displacement is estimated with basic physics. Power is deduced from a photo- detector looking at beam pickoff.

LIGO-G I H1 XarmH1 YarmH2 XarmH2 YarmL1 XarmL1 Yarm Pcal/Ocal ratioN/A Date measuredSept. 28, 06Nov. 8, 06 Mar. 16, 07 Ratio of ETM coil calibration factors (m/ct) measured using the photon calibrators to those measured using the official calibration technique (mean of values over the frequency range from 50 to 400 Hz). H1 ETMY coil actuation coefficients determined by the official calibration procedure (blue) and by the photon calibrator (red). The transfer functions have been multiplied by the square of the measurement frequency to flatten the plots. H1 ETMY coil actuation coefficients Actuation coeff. x f^2 Frequency (Hz) Photon calibrator Official calibration

LIGO-G I Landry - L/V meeting, 22 May High-frequency calibration AS_Q_FAST channels 262kHz sampling rate Signals digitally heterodyned at 1024Hz (AS_Q_0FSR) and kHz (AS_Q_1FSR) at 2048Hz sampling rate Introduction S4 calibration review underway S5 calibration Post-S5 measurements to ensure quality

LIGO-G I Landry - L/V meeting, 22 May Closing S5 calibration issues »Many measurements over a long run: multiple epochs, discrepancies to understand. Complicates data production and calibration validation »What to do with short epochs? Data quality flags or special calibrations? »Events like GRB require confidence in online calibration All calibration flavours will require IFO configuration freezes at the end of S5: suite of measurements, both in control room and on the floor