Homestake meeting, 03/06/2014
Attending: Nelson, Tanner, Vuk, Noah, Eric, Victor, Gabor S
Homestake wiki: https://zzz.physics.umn.edu/groups/homestake/home
1) Homestake update (Vuk)
Spoke with SURF representatives. Batteries are OK for them, as long as we don't have to visit them monthly. Fibers are single mode, and have them both in Ross and Yates shafts. The Ross bundle has very few fibers free, though. Since neither shaft can access all levels, we will likely have to have two separate GPS distribution systems. In the process of putting paperwork together to start the activities.
Received from Optical Zonu a transmitter/receiver for the raw GPS signal. Tanner starting to play with it.
Also working with Liteway and ViaLite. Liteway's approach is to digitize the GPS signal at the surface and transmit the digital signals down into the mine. Ordered demo equipment which should arrive in a week or so.
Vialite's approach is hybrid: send the raw GPS signal down into the mine via optical fibers, and at each level convert it to digital signals which are then sent to each station on that level. Ordered some demo equipment to do the raw GPS part of this, should have it in a week or two.
2) UMN test setup (Tanner)
Received the Optical Zonu set up, plug the GPS antenna into transmitter, which converts it to optical, sends it to a receiver via fiber, and receiver converts it back to RF. Seems to work well, there is a bit of a loss in the signal-to-noise ratio, at 10% level (from 50-ish to 42-45). Concern with losses in longer cables, and in splittings.
Also working on how to interact with the digitizer and baler, with Gary's help. Using Antelope software and the software provided by Quanterra. Antelope should be much better. Part of the difficulty is that interaction with the baler is difficult, have to go through the digitizer. Have a way to get the data now: use Quanterra software that turns on the baler, then use Antelope to assign IP to the baler and then use wget to get the data from the baler. Next step is to use Antelope to sort the data according to the recording time. This should work, but it is manual - could do it once/week or so. It may also be possible to copy the data from the digitizer directly to a computer continuously, Gary might know.
Victor: could also ask PASSCAL people for advice, there may be better ways to access the baler remotely.
Tanner: this was also Gary's suggestion. Also, there are two types of balers, one of them (which we don't have) can be assigned a permanent address.
3) Analysis of existing data
a) Frames/miniSEED files (Shivaraj, Tanner, Michael) b) Wiener filtering (Michael, Jan) c) Estimation algorithms (Shivaraj, Eric, Noah)
Eric: Noah and Eric putting together code package to simulate a seismic field which can then be given to the radiometer code for analysis. Eric wrote a code for generate P-waves, Noah is redoing it for S-waves. This is a bit harder because it includes polarization. Trying to work out the cleanest way to handle polarization, Eric suggested to use Euler angles which are standard when dealing with Polarization. Noah wrote a code to do this, should now check it. Noah posted a note in the SVN repository about the S-wave convention.
Eric: Also, last time we discussed the turning depth. Eric and Victor plan to get together and put a note together.
Vuk: next call in 4 weeks.