SSP2012 - 5th International Symposium on Symmetries in Subatomic Physics

W. Heil(1), F. Allendinger(3), C. Gemmel(1), S. Karpuk(1), Yu.Sobolev(1) , K.Tullney(1), M.Burghoff(2), W. Kilian(2), S.Knappe-Grüneberg(2), W.Müller(2), A.Schnabel(2), F.Seifert(2), L.Trahms(2), and U.Schmidt(3) 1Institut für Physik, 55099 Mainz, Germany 2Physikalisch-Technische Bundesanstalt, 10587 Berlin, Germany 3University of Heidelberg, Germany We discuss the design and performance of a very sensitive low-field magnetometer based on the detection of free spin precession of gaseous, nuclear polarized 3He or 129Xe samples with a SQUID as magnetic flux detector. Characteristic spin precession times of up to 60 h were measured in low magnetic fields (about 1µT) and in the regime of motional narrowing. The achieved signal-to-noise ratio of more than 5000:1 leads to an expected sensitivity level (Cramer-Rao Lower Bound) of (100 Zeptotesla) after one day [1]. With the detection of the free precession of co-located 3He/129Xe nuclear spins ( clock comparison), the device can be used as ultra-sensitive probe for non-magnetic spin interactions, since the magnetic dipole interaction (Zeeman-term) drops out in the weighted frequency difference, i.e., dw=w_He- g_He/g_Xe*w_Xe . We report on searches for Lorentz violating signatures by monitoring the Larmor frequencies of co-located 3He/129Xe spin samples as the laboratory reference frame rotates with respect to distant stars (sidereal modulation) [2]. [1] C.Gemmel, W.Heil, S.Karpuk, et al., Eur. Phys. J. D, 47, 303-320, (2010) [2] C. Gemmel, W. Heil, S. Karpuk, et al., Phys. Rev D 82, 111901(R) (2010)