This site is a temporary location to facilitate coordination of smaller experiments at the Soudan Underground Lab after the Shaft Fire. By prioritizing our needs here, we can then present an organized set of jobs to help the crew. This will minimize the flow of emails directly to personnel currently engaged in the recovery. In addition, I will continue to update information (see the “Update” section at the bottom), so that you will know when entry will be possible.

Please feel free to login (first time will create account) and edit your section. I have put a few placeholders to show how this might work. Immediate needs refers to jobs you would like done by the mine crew as soon as there is any access. I have already communicated the need for SOLO, Gopher, and CoGeNT to keep radon plateout to a minimum.

Nitrogen purge for radon reduction (LN boiloff or N2 compressed gas)

When switching off power to the experiment, please preserve an AC ground (i.e., do not allow CoGeNT electronics to “float”). Make sure both NIM bins are OFF, same for Canberra and Ortec HV power supplies on top bin, besides all other measures to keep power off the experiment.

As soon as is possible, please flush room-temperature gas (preferably compressed nitrogen, but any other *moisture-free* gas will do) through the input to the detector Dewar, presently attached to a 200 liter LN2 tank. Do so (at low flow, over one or two days) until the temperature of the gas coming through the latex hose exhaust is measured to be room temperature. Please do not alter (at all) the position of the thermocouple inserted into that exhaust when measuring this temperature. Because the detector cold finger does not reach the bottom of the detector Dewar, and the Dewar is new and carefully sealed, there is not much of a heat load to the bottom ~1/3 of the LN2 presently in there. If this procedure is not performed, that bottom layer could stay there for a number of weeks, keeping the detector from truly thermalizing at room temperature, a condition that must be ensured for a number of days prior to refilling/restarting. Please let us know when this is attempted and how long it took to reach room-T at the exhaust.

Please contact us about ten days before the date when you envision being able to receive one of us in the lab to restart the experiment, also foreseeing continued LN2 availability (must have that before we can think of restarting). We'll have a few more instructions for preparation then. THANKS.

Nitrogen purge for radon reduction (LN boiloff or N2 compressed gas)

Nitrogen purge for radon reduction (LN boiloff or N2 compressed gas)

No immediate needs… the detector should have weathered the loss in power relatively unharmed. We won't know for sure, however, until the power returns. Continued updates regarding the status of the cleanup and the return of power are our only short-term needs… various individuals have and are providing adequate information.

Once we have power, I will need some on-site assistance in turning our DAQ computers & electronics back on. We will need to assess the state of the three UPS backups… provided the backups can still provide power to their respective components, the experiment should be operable again almost immediately. Again, I'll know more once we have power. -Ray Bunker (805.280.1076 … raybunker@gmail.com)

If it is necessary to move the gravity meters then they should be clamped first.

Restart the two gravity meters and adjust the long and cross levels.

Whenever possible, I would like to bring the meter that is supported by foam back to my home. If I am allowed to bring the instrument to the surface then I can come any time. If someone else does this then the meter should be clamped first and I can meet them at the surface.

There was continued work in the shaft today and a brief entry into the Soudan Lab.

• Today's shaft work focused on straightening a section of rail about 100 feet above the 27th level.

• The electrical cable between the 27th level substation and the lab was tested and passed with no faults.

• The foam in the lab has collapsed to the floor, leaving some debris that was swept into the lab by the foam in the area between the entryway and the MINOS Detector.

• All doors to the lab are now closed at the suggestion of Fermilab engineers.

• The DNR and University staff have now worked continuously since last Thursday night. There will be no work this weekend, in order to rest the staff for next week. Work will resume on Monday. Steps are being taken now to augment the staff in order to provide longer access to the Lab for cleanup.

• Next report will be Monday.