University of Minnesota
School of Physics & Astronomy

Research Spotlight

In Control

Marianna Gabrielyan
Marianna Gabrielyan, NOvA collaboration.
Richard Anderson

Marianna Gabrielyan is a postdoctoral researcher in the NOVA collaboration. Though she came on board the experiment to do data analysis, she has found herself responsible for quite a bit of the hardware on the NOVA project. Gabrielyan recently setup a control room in the Physics and Nanotechnology Building. This control room will eventually allow researchers at the U in the Twin Cities to take shifts monitoring both Near and Far detectors, a function that is presently done at Fermilab, outside of Chicago.

The Near detector is located in Fermilab, while the Far detector is located in Ash River, MN, between Ely and International Falls. Remote control of the detectors allows physicists to continue to monitor the experiment without the travel. Gabrielyan explains that several times a year, every member of the collaboration is expected to take a shift at the controls of the detector. At the present time, each shift costs the School about $3,000 in travel expenses. Multiplied throughout the collaboration members at the U, this bill is about $70k per year.

The room also has the advantage of being an excellent place to learn how to work the controls. Trainees can log in remotely and see the experts at Fermilab do their work. Physicists call this “shadowing” and they’ve done some effective demonstrations. At a recent collaboration meeting the group successfully ran shadow shifts to prove the collaboration as a whole that the control room in Minneapolis is adequately set-up to monitor the detector. Gabrielyan says that they will be doing official shifts from the remote control room at the University starting November 2014.

Gabrielyan is also on call 24/7 as the power supply and detector controls expert for both detectors. Both Near and Far detectors run on a series of Avalanche Photo Diodes (APD) that have to be cooled to -15C to reduce the noise levels. Shift workers need to constantly monitor the APD temperatures. Since a large amount of water is used in the cooling system, to prevent any physical damage to detectors, the interlock system is enabled to automatically shut down the power in case of a water leak or other mechanical failure. To return the detector to normal, running state, Gabrielyan is called in to run through a series of protocols that allow things to reset and return control to the shifters who are monitoring.

Gabrielyan is also working on analysis of the first run of NOVA data as well as MINOS data. She is currently analyzing MINOS data of electron neutrino appearance for non-standard interactions, refining her analysis based on theory. One of the questions that NOVA hopes to answer is that of the mass hierarchy—which of the three neutrino “flavors” (the name given to the various types of neutrinos) has the highest mass, which has the next highest and so on. It is a well-known fact that different neutrino “flavors” oscillate into one another when traveling a long distance. There are certain mathematical parameters associated with these oscillations, one of which could possibly shed light on physicists’ understanding of the matter/antimatter asymmetry in the universe.