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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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)
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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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Oregon Proposal, Jim Brau, PAC, December 5, 2002
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Oregon Proposal, Jim Brau, PAC, December 5, 2002
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http://apex.ligo-wa.caltech.edu/~roberts/PEMfrequencies.pdf
G010395-00-Z
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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
AS_Q
G000396-00-D
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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• Identify specific sources - external sources
• e.g. Nuclear power plant fans, trucks
I. Improve Sensitivity and Decrease False Detection Rates at
Individual Interferometers by Reducing Environmental Influences
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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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Nuclear Power Plant Fans(36 cooling fans)
G000396-00-D
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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• Identify specific sources - external sources
• e.g. Nuclear power plant fans, trucks
I. Improve Sensitivity and Decrease False Detection Rates at
Individual Interferometers by Reducing Environmental Influences
G000262-00-D
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I. Improve Sensitivity and Decrease False Detection Rates at
Individual Interferometers by Reducing Environmental Influences
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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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Reduced Data Sets
Gain in access time by RDS for 640 seconds of data and 1280 seconds of data
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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).
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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
Oregon Proposal, Jim Brau, PAC, December 5, 2002
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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…