PRECISE SEARCH FOR VIOLATION OF TIME-REVERSAL INVARIANCE IN NUCLEAR DECAY SUS IN GLOW-TEMPERATURE NUCLEAR POLARIZATION

通过观察在9.3（1）mK低温下极化的^ IrFe源的^ Pt中混合（E2，M1）γ跃迁的线性极化角分布，研究了γ跃迁的时间反转不变性<192><192>。作为旋光计，使用了四个薄盘型（两个44 mmPHIX 15 mm，两个51 mmPHIX 20 mm）探测器。这些探测器可以在单次γ射线测量中探测到线偏振。用这种方法可以在不使用符合电路的情况下，以高能量分辨率测量线偏振。它们被放置在彼此对称的位置处，并且相对于自旋方向成54.7度和125.3度的角度。测量了308-、484-和604-ke V γ射线的不对称性。对308、484和604 keV γ跃迁，sin（eta+Xi）的相角分别为1（14）× 10 ~<-3>（-1）、0（30）× 10 ~（-1）<-3>和2.1（53）× 10 <-3>~（-1）。为了提高探测器的偏振灵敏度，我们采用了更薄的探测器（两个51 mmPHIx 7 mm）。测量进行约35天。实验结果表明，对于604 keV跃迁，探测器1 -4的sin（eta+Xi）值分别为-26（25）× 10 ^<-4>，-80（74）× 10 ^<-4>，-30（28）× 10 ^<-4>，90（94）× 10 ^<-4>。详细分析正在进行中。

Time-reversal invariance in the gamma transitions were investigated by observing the angular distribution of the linear polarization of the mixed (E2, M1) gamma transitions in ^<192>Pt from a source of ^<192>IrFe polarized at a low temperature of 9.3 (1) mK.As the polarimeters, four thin disk-type (two 44mmPHIx15mm, two 51mmPHIx20mm) detectors were used. The linear polarization could be detected in single gamma-ray measurements by these detectors. By this method it is possible to measure the linear polarization with high energy resolution without troubles of coincidence circuits. They were placed at the symmetric positions each other and at the angles of 54.7 and 125.3 degree with respect to the spin direction. The asymmetries of the 308-, 484- and 604-ke Vgamma rays were measured. Values of phase angles of sin (eta+xi) were obtained to be 1(14) x10^<-3>,0 (30) x10^<-3> and 2.1 (53) x10^<-3> for the 308-, 484- and 604-ke Vgamma transitions, respectively. These results are consistent with time reversal invariance.In order to improve the polarization sensitivity we employed more thinner detectors (two 51mmPHIx7mm) . The measurements were performed for about 35 days. Now the result of the value ofsin (eta+xi) for the 604-keV transition were tentatively obtainde ; -26 (25) x10^<-4>, -80 (74) x10^<-4>, -30 (28) x10^<-4>,90 (94) x10^<-4> for the detector Nos.1-4 respectively. Detailed analyzes are now in progress.