Magnetometry at the fTesla-scale for neutron EDM experiments

新的中子EDM实验，如保罗·谢勒研究所（PSI）的国际中子EDM合作或FRM-II的nEDM合作，旨在达到10-28 e·cm的测量灵敏度，与目前中子EDM的上限dn<3x 10 -26 e·cm相比，提高了两个数量级。为了实现这一宏伟目标，需要在200 s的典型Ramsey循环期间达到fTesla灵敏度水平的磁力测量。在这个建议中，我们集中在现有的3 He磁强计的调试和操作，这是基于检测的气体，核极化3 He样品的自由自旋进动，应该能够监测磁场波动在FT-水平，并纠正几何相位引起的假nEDM效应。这些假效应设定了dn的当前系统极限，假的是10-26 ecm，并且是由相对论xE场与现有磁场梯度的相互作用引起的，导致与电场线性的频移，模仿nEDM。

Novel neutron EDM experiments, like the international neutron EDM collaboration at the Paul Scherrer Institute (PSI) or the nEDM collaboration at FRM-II aim to reach a measurement sensitivity of ≈10-28 e∙cm, a two orders of magnitude improvement compared to the present upper limit of dn< 3x10-26 e∙cm for the neutron EDM. In order to reach this ambitious goal, magnetometry reaching the fTesla sensitivity level during a typical Ramsey cycle of 200 s is demanded. In this proposal we concentrate on the commissioning and operation of an existing 3He magnetometer which is based on the detection of free spin-precession of gaseous, nuclear polarized 3He samples and which should be able to monitor magnetic field fluctuations at the fT-level and to correct geometric phase induced false nEDM effects. These false effects set the present systematic limit of dn, false ≈10-26 ecm and result from the interplay of the relativistic xE-field with existing magnetic field gradients causing a frequency shift linear to the electric field mimicking an nEDM.