Homestake Meeting Minutes, 06/25/15

Attending: Tanner, Daniel, Levi, Vuk, Victor, Riccardo, Gary

Homestake wiki: https://zzz.physics.umn.edu/groups/homestake/home

Our agenda:

1) Homestake array status (Gary, Tanner, Daniel, Pat)

• Daniel: two stations on 4100 are still down, there was a fiber failure yesterday. Jamey thinks timing should still be getting to them. They should still be working and data logging, but we may have to get the data from the baler eventually.
• Gary: progress with the highschool, but didn't solve it yet. Should probably call the network person there to fix it.
• IRIS has caught up with our data.
• Tanner: still have problems with antelope at UMN. Admin started working on it yesterday, trying to monitor the relevant processes and the disk on which the software is running. Data flowing to Caltech at least most of the time. Copied data from Homestake to UMN to fill all gaps. There is a small gap now at Caltech.
• Daniel: how many transceiver/splitters do we have left. Vuk check.

2) Next Homestake trip

• Gary: talked to PASSCAL that affects the schedule - they can get the equipment to Homestake by Sep 15. So the underground excitations will have to take place after the surface. Can do surface Sep 11-14. PASSCAL has a device that plugs into the data logger computer that Lee is bringing, which syncs the computer time to UTC, so that the data tagged on each shot (weight drop) is accurate to better than ms. The weight flips a switch when it hits the ground, and this gives the time of the drop/hit.
• Riccardo/Gary: there is a coupling problem, whether you are on rock or sand makes a difference. Will have to study this. Compressible ground will reduce the high frequency component, could affect the travel time measurements. Lee's surface streamer will give us information about near surface, could be used in analysis.
• For the underground work, will need 2 weeks of underground access.
• Homestake no access on Aug 31, Sep 7, Sep 11-14, Sep 25-28)
• would be good for another person (Pat or Daniel) to go to Homestake on 9/8 and use the two underground days before Sep 11 to fix 2000E and harvest the data from Balers.
• Both Victor and Daniel might be going to a workshop on Sep 13-16.
• Tasks:
  • weight drop experiments on the surface
  • check on the 4 stations not online
  • fix telemetry on LHS
  • fix 2000E (new concrete pad and tile, re-orienting)
  • replace balers on several stations (Ross, Yates, and probably some underground)
  • underground excitation experiments
  • look at the failed splitters and GPS transceivers

3) data analysis

• calibration: Gary knows how to do it, has to find time to run it and watch it. Takes about 3 hours per station. Can automate the process, so the whole array will take about 2-3 days.
• Daniel: deep earthquake in Japan, trying to look at the free surface reflection. Trying to model the waveform, work in progress.
• radiometer method: Tanner rewriting some of the code to streamline it and make it more coherent. Doing comparisons recently between the new and the old codes and the new code is still having problems with the S-wave. ALso trying to add capability to look at the real data from Homestake. Also need information about how to apply calibration - to start with, a multiplicative factor in time-domain would do.
• Levi: looking at the power in the recovered maps, now have code ready to make histograms and study dependence in the detector configurations.
• Gary: nominal calibration constants are in the stage table in db.master. Conversion from counts to nm/s.
• analysis workshop: October 10 +- 7 Gary is not available. Vuk to follow up.

Next call July 23.