Jim Brau Univ. of Oregon December 5, 2002

Oregon Proposal, Jim Brau, PAC, December 5, 2002

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Jim BrauUniv. of Oregon

December 5, 2002

Oregon Proposal for LIGO Research

LSC collaborator since formation of LSC in 1997

Research aimed at search for burst sources of gravity waves

Recognize identification and amelioration of noise sources is prerequisite

(principal focus of Oregon effort)

Future effort will build on our energetic engagement in LIGO “shake-down”

Expand effort in data analysis most connected to our past involvements,and consistent with our astrophysical goals


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Faculty: Jim Brau Ray Frey David Strom Research associates: Isabel Leonor Robert Schofield (1/2 time at LHO) Nikolai Sinev

Graduate students: Masahiro Ito (full time at LHO) Rauha Rahkola (full time at LHO last yr,

1/2 time at LHO now) Brian Stubbs

Oregon LIGO Group


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PHYSICS GOALS

• Gravitational Wave Bursts

– externally triggered searches and untriggered searches

– Gamma Ray Bursts are prototypical (although likely too distant)

• we are looking

– In order to develop our ability to find GW bursts in the data stream, we were drawn to the Physics Environment Monitoring, where many potential sources of burst backgrounds appear


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Externally-triggered Bursts Search

• R. Rahkola developed ETG (aka DSO) which applies statistical method of Finn, Mohanty, and Romano: compare on-source and off-source distributions of cross-correlation statistic – Tested with E7 playground data– Applied to S1

• Only one event in S1 coincident with LLO*LHO– HETE X-Ray flare

• Currently finalizing S1 search write-up for Bursts UL group

• Preparing for S2


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Past Research• Assisted in setting up the Physics Environment

Monitoring System (PEM)• Identified, studied, and helped reduce sources of

environmental coupling to the interferometers– magnetic fields, seismic signals, acoustic, radio frequency, weather,

developed cosmic ray detector

• Investigated between-site environmental correlations• Developed data analysis, monitoring and distribution

software• Produced veto monitors

(continued)


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Past Research(continued)

• Contributed to Advanced LIGO• Performed numerous commissioning activities• Shift participation (manned about 1/5 of LHO)• S1 detector characterization investigations

– 13 LSC investigations– 6 lead or co-lead by Oregon physicists

• Glitches (rates, causes) M. Ito• Quantify correlated enviromental transients

between sites R. Schofield, R. Frey

• Identify & catalog environmental disturbances R. Schofield, R. Rahkola• Data quality R. Rahkola, R. Schofield• Data set reduction I. Leonor• Hardware astrophysical signal injection I. Leonor


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Proposed Research(2003-2006)

I. Improve Sensitivity and Decrease False Detection Rates at Individual Interferometers by Reducing Environmental Influences

II. Study and Reduce the False Coincidence Rates Between the Three Interferometers

III. Develop Astrophysical Analysis Methods, Data Quality Monitoring Tools, and Methods for Data Distribution

• continuation of past investigations• expand activities to Livingston• contribute in many areas of our activity to development of Advanced LIGO


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I. Improve Sensitivity and Decrease False Detection Rates at

Individual Interferometers by Reducing Environmental Influences

• Identify specific sources

– internal sources• e.g. Periscope, office air handler, PSL table legs,

test mass controller fans

– external sources• e.g. Nuclear power plant fans, trucks

• Reduce environmental coupling


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http://apex.ligo-wa.caltech.edu/~roberts/PEMfrequencies.pdf

G010395-00-Z


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• Identify specific sources - internal sources

• e.g. Periscope, office air handler, PSL table legs, test mass controller fans

AS_Q

G000396-00-D


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• Identify specific sources - external sources

• e.g. Nuclear power plant fans, trucks



Peak at 2.295 Hz responsible for 20% of RMS is 4k mode cleaner control (MC_F)

Effect reduced by resonant gain stage, but still responsible for several percent of RMS of HAM2 coils.

What is the source?

Mobile seismometer suggests cooling towers at ENW nuclear power plant

G000396-00-D


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Nuclear Power Plant Fans(36 cooling fans)

G000396-00-D


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• Identify specific sources - external sources

• e.g. Nuclear power plant fans, trucks



G000262-00-D


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elog-08/23/2002-16:26

H2:LSC-AS_Q H2:LSC-AS_Q

H0:PEM-HAM10_MIC H0:PEM-PSL2_MIC

• Acoustic coupling (resulting from test bursts)

– acoustic coupling at two different locations during S1, demonstrating the need for PEM vetoes


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II. Study and Reduce the False Coincidence Rates

Between the Three Interferometers

• Monitor inter-site environmental correlations

– e.g. Lightning strikes are potential sources

• Characterize the false coincidence rate between the two Hanford interferometers

– Many mechanisms reduce independence of Hanford interferometers


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Lightning Strikes• Stand alone code developed to

search for intersite events by locating coincidences in 15 ms window for aligned and misaligned time series

• High rate of intersite bursts on coil magnetometer (probably lightning)

• No detection on voltage monitors, seismometers, MC_F, fluxgate magnetometers

• No evidence on other channels

– studies are continuing

G020253-00-Z


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III. Develop Astrophysical Analysis Methods, Data Quality Monitoring Tools,

and Methods for Data Distribution

• Reduced Data Sets

• Externally triggered burst search analysis code

• Glitch detectors and other monitors

– e.g. glitchMon, absGlitch

• Event processing and coincidence analysis tools– e.g. EventTool


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Reduced Data Sets

http://darkwing.uoregon.edu/ ~ileonor/ligo/s1/rds/ s1rds.html

•5-fold reduction in total S1 data volume from channel selection and downsampling

•22-fold reduction in total number of channels•channel list will be refined for future science runs; goal is to reduce

data volume by factor for ten or more•studies were done on the feasibility of performing resampling on frame data using a linear filter and correcting for the time delay before saving resampled data in frame format, so that unwanted filtering effects are transparent to the end user (see http://darkwing.uoregon.edu/~ileonor/rds/ligords_0201.pdf)

Working closely withLDAS team to developeffective RDS


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Reduced Data Sets

Gain in access time by RDS for 640 seconds of data and 1280 seconds of data


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Proposal to Expand Activities to Livingston

• New postdoctoral research associate at LLOworking closely with R. Schofield at

Hanford• Measure magnetic, acoustic, seismic, and RF

coupling at all three Livingston stations• Work to reduce coupling• Work with local staff to expand environmental

monitoring, as planned at Hanford• Other work outlined in proposal


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Advanced LIGO

• Many proposed activities contribute to Advanced LIGO, as have our past efforts:

• Showed that Newtonian noise may limit the sensitivity of Advanced LIGO below 10 Hz (T010074-03-D).

• Measured statistics of earthquake motion for planning of Advanced LIGO control system (G010017-00-1).

• Contributed extensively to the environmental assessment for Advanced LIGO (T010074-03-D).

• Measured ambient magnetic fields, transfer functions to vacuum chambers, and coupling to the interferometer (G990079-29-M).


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Newtonian Noise Limit

SchofieldHughes &

Thorne

T010074-03-D

• 3 - 10 Hz based on typical truck traffic excitation at Yend station, anisotropy ratio of 1, and an assumption of fund. Rayleigh and Love modes (propagation velocity of 450 m/sec)

• 20 - 30 Hz based on measurements in the LVEA with minimum equipment operating (no 4k racks at that time), and assumed a Raleigh mode


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SummaryOregon Research aimed at search for burst sources of gravity waves

I. Improve Sensitivity and Decrease False Detection Rates at Individual Interferometers by Reducing Environmental Influences

II. Study and Reduce the False Coincidence Rates Between the Three Interferometers

III. Develop Astrophysical Analysis Methods, Data Quality Monitoring Tools, and Methods for Data Distribution

Expand effort to Livingston

Build on our energetic engagement in LIGO “shake-down”

I have shown a sampling of studies by the Oregon group

Please refer to the proposal for a complete list


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• Extra transparencies follow


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Cosmic Ray DetectorsA very energetic cosmic ray shower incident on a test mass could, in principle, create a background to gravity wave searches.

The two mechanisms usually considered are (1) the transfer of the particle momenta (impulse) to the test mass; (2) the loss of particle energy resulting in internal-mode

excitations within the test mass.

A. Marin, “Cosmic Muon Signature in LIGO,” 1998.

Estimates place the effects of cosmic rays to be a few ordersof magnitude below LIGO sensitivity.

Still, it is important to have an independent monitor check estimates and confirm size for Advanced LIGO


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Cosmic Ray Detectors


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HETE location for XRF in S1


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Tuning Pipeline

Create c.c. statistic distributions for all data sets

Baseline Data Conditioning

Time-domain conditioning •Split hanning window•Approximate calibration filter

Fourier-domain conditioning •Frequency-region removal

2nd Time-domain conditioning •Bandpass filter•Extract middle of data

Input:•sets of representative data excluding lock stretch containing astrophysical trigger

•approximate calibration transfer function

Output:Final data conditioning routine for Data Analysis pipeline

Create c.c. statistic distributions for all data sets

Input:•sets of data within lock stretch– but excluding surrounding ± 2 hours– containing astrophysical trigger Validating Data Conditioning

Time-domain conditioning •Split Hanning Window•Approximate Calibration Filter

Fourier-domain conditioning •Frequency-region removal

2nd Time-domain conditioning •Bandpass filter•Extract middle of data

List of frequency regions to be removed(start with 60Hz harmonics)

Compare spectra of “best” and “worst” distributions

Add non-stationary frequency regions to list

Tuning the Data Conditioning

Are the c.c. distributions stationary?

1st Yes

No

2nd Yes


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Data Analysis Pipeline

Upper Limit on hrms

(Statistical Method)

Account for data conditioning (missing frequencies) by proportionality factor

Input:•Astrophysical trigger time, source direction•Conditioned, approximately calibrated data within lock stretch containing astrophysical trigger (excluding data used in Tuning Pipeline)

•Simulated bursts (white noise, 1ms Gaussian) of known strain, conditioned like data

Create ‘off-source’ distribution of c.c. statistics - times not associated with trigger - close enough for data to be stationary

Calculate ‘on-source’ statistic - time associated with trigger - time delay calculated from trigger source direction, timestamp

Determine significance of ‘on-source’ c.c. statistic (upper limit) using Feldman-Cousins, table X

Upper Limit on C.C. Statistic

Upper limit applies to simulated burst type only

Upper Limit on hrms

(Method of Injections)

Create ‘off-source’ distribution with injected bursts

Choose a burst of known strain

Modify injected burst’s amplitude appropriately

Is the distribution mean just

outside the F-C upper limit?

No

Yes


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S1 Document nearly complete…

Documents

Jim Brau Univ. of Oregon December 5, 2002