The rst production of polarized Hydrogen-Deuteride(HD) target at RCNP

The polarized Hydrogen-Deuteride(HD) target is developed mainly for the study of ϕmeson photoproduction on the proton and neutron. Using the polarized target and polarized photon beam at SPring-8, one can measure double polarization asymmetries to investigate the ss-content in the nucleon [1] and the bump found in the ϕ meson production cross sections [2]. The proton in the HD is polarized by using the static method at low temperature and high magnetic eld [3]. The polarization degree of 82 % is principally possible for the proton. For 5 years up to now, we have prepared to produce the polarized HD target. We carried out an experiment to polarize the HD target for the rst time. The main purpose of this experiment is to measure the polarization degree and the relaxation time T1 of the HD target. The HD was solidi ed, and the polarization was frozen by aging it at 15 mK and 17 T. After 53 days, we measured NMR signals of the HD target. Figure 1 shows the rst NMR signal of the HD target and cell. The H peak from the HD and the F ( uorine) peak from PCTFE(Kel-F) cell were conrmed. Then the relaxation time was estimated by measuring the intensities of the NMR signals. It's quite interesting that the polarization of F decreased quickly, while that of H was maintained for a long time (Fig. 2)[4]. The polarization degree of H was 42 % which is lower than the expected value(82%), and That of D was 13%. Calibration data for the polarization were taken at 4.2 K