Using Dawn’s GRaND Instrument to Detect a Magnetic Field at Vesta

Friday, 19 December 2014
Michaela Nicole Villarreal1, Naoyuki Yamashita2, Thomas H Prettyman2 and Christopher T Russell3, (1)University of California Los Angeles, Los Angeles, CA, United States, (2)Planetary Science Institute Tucson, Tucson, AZ, United States, (3)Univ California, Los Angeles, CA, United States
The Dawn spacecraft does not carry a magnetometer and thus cannot measure directly any magnetic field that may be present at Vesta. However, the photomultiplier tube associated with the Bismuth Germanate (BGO) scintillator that is part of Dawn’s Gamma Ray and Neutron Detector (GRaND) instrument is known to be sensitive to strong magnetic fields. The output of the gain for the photomultiplier tube varies with both the magnitude and direction of the present magnetic field. Knowing this, we can use the variation of the gain of the photomultiplier tube as a proxy for any crustal remanent fields that may be present as Dawn orbits Vesta. We report our results here.