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

在低温9.3 (1)mk下，通过观察^<192>Pt中混合（E2, M1）伽玛跃迁的线偏振角分布，研究了伽玛跃迁的时间反转不变性。作为偏振计，使用了4个薄盘型（2个44mmPHIx15mm， 2个51mmPHIx20mm）探测器。这些探测器可以在单伽马射线测量中检测到线性偏振。用这种方法可以测量出高能量分辨率的线极化，而不需要考虑重合电路的问题。它们被放置在彼此对称的位置，并以54.7度和125.3度的角度相对于自旋方向。测量了308-，484-和604-ke v伽马射线的不对称性。在308-、484-和604-ke Vgamma跃迁中，sin （eta+xi）的相位角值分别为1(14)x10^<-3>、0 (30)x10^<-3>和2.1 (53)x10^<-3>。这些结果符合时间反转不变性。为了提高偏振灵敏度，我们采用了更薄的探测器（两个51mmPHIx7mm）。测量进行了大约35天。现在初步得到了604 kev跃迁时的sin （eta+xi）值；1-4号探测器分别为-26 (25)x10^<-4>、-80 (74)x10^<-4>、-30 (28)x10^<-4>、90 (94)x10^<-4>。详细的分析正在进行中。

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.