Detector calibration R&D - 1

• Elastic deformation of test masses» R. Savage with Pablo Daveloza (LIGO fellowship) and Mario Diaz – UTB and

Mahmuda Afrin Badhan – SURF (with M. Landry and P. Willems)

• Goal: compensation for calibration errors due to TM distortions caused by actuation and calibration forces

• Results:» accounts for more than 90% of observed actuation discrepancy at high frequencies» found optimum location for photon calibrator beams to minimize calibration errors due to elastic

deformation» Future: analysis of aLIGO ETMs with electrostatic drive

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H1 actuation discrepancy

Detector calibration R&D - 2

• Photon calibrator development» R. Savage, J. Berliner, and M. Sakosky

with Roberto Grosso – UTB, Matt West – Syracuse, Ryan DeRosa – LSU, and Alberto Sottile – U of Pisa

• Goal: development of technique, hardware,and analysis methods for aLIGO calibration

• Results:» Design, fabrication, installation, and operation of

eLIGO Pcals» Continued investigation of accuracy and stability of

Gold and Working standards (absolute power)

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LLO Pcal swept sine

Continuous Pcal calibration lines in both H1 and L1 during all of S6

Detector calibration R&D - 3

• Photon calibrator data characterization• Discovery of long-term stability of voice coil and photon calibrator actuation chains, and photon

calibrator analysis method

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Alberto Sottile, senior thesis U of Pisa (with R. Gross and J. Berliner)

aLIGO PSL table legs

• Design of table legs and scheme for mounting and interfacing with PSL table» R. Savage and M. Rodruck with Demetrio Corralez – UTEP, Robert Schofield – U of O, and

Riccardo DeSalvo – CIT

• Goal: reduction of table (periscope) motion by optimum location of legs and improved design of legs and interface with LVEA floor and table surface

• Results:» factor of ten improvement in RMS displacement over iLIGO legs

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On-line RFAM monitoring

• development of technique for monitoring RFAM downstream of the suspended modecleaner

» R. Savage with Volker Quetschke – UTB

• Goal: characterize RFAM downstream of the MC as a function of operating laser power

• Results:» hardware designed, fabricated, and installed on

H1. Both quadratures being recorded in the DAQ (2 kHz channels) for all of S6.

» assessment of results in progress» development of DMT monitor planned – with R.

Grosso - UTB

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S6 data

20 W

PMC loss characterization

• Measurement of optical losses and mode distortion at high power

» R. Savage with Malik Rakhmanov, Volker Quetschke, and Sergio Cantu – UTB

• Goal: tracking of long term optical losses with few-ppm resolution and understanding impact of PMC contamination at aLIGO circulating power levels

• Results:» fabrication of spare PMCs for eLIGO (lowest losses of any PMCs)» improvement of characterization method – few-ppm level

achieved» 10-W laser on loan to UTB now operating in lab; PMC

characterization set-up under construction

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