Zhan-Kui Li

Newβ-delayed proton precursor135Gd

Unknownβ-delayed proton precursor135Gd has been synthesized by the reaction106Cd (32S, 3n) and identified using a helium-jet recoil fast tape-transport system with aγ(X)-p coincidence measurements. Itsβ-delayed proton spectrum has been observed. The half-life of135Gd decay has been determined to be 1.1±0.2 s.

Neaw β-delayed proton precursor121Ce near the proton drip-line

Unknown β-delayed proton precursor121Ce was produced via the reaction of92Mo(32S, 3n), and identified by an He-jet fast tape transport system with “P-γ” coincidence measurements. The half-life of121Ce decay was determined to be (1.1 ± 0. l)s. Its energy spectrum of β-delayed protons was measured and the β-delayed proton branching ratio for121decay was roughly estimated to be ∼ 1 %. After β-delayed proton decay of the precursors119Ba,121Ba and122La, some of γ-transitions from low-lying states to the ground states in their “daughters” were observed for the first time.

β-delayed proton decays near the proton drip line

We briefly reviewed the experimental study on β-delayed proton decays near the proton drip line published by our group during the period of 1996–2004, namely the first observation of the β-delayed proton decays of 9 new nuclides in the rare-earth region and the new measurements of β-delayed proton decays of 5 nuclides in the mass ∼90 region near theN=Z line with the aid of the “p-y” coincidence in combination with a He-jet tape transport system. In the meantime some important experimental technique details were supplemented. The experimental results, including the half-lives, spins, parities, deformations and production reaction cross sections for the 14 nuclei were summarized and compared with the current nuclear-model predictions, and then the following points were represented. (1) The experimental half-lives for85Mo and92Rh as well as the predicted “waiting point” nuclei89Ru and93Pd are 5–10 times longer than the theoretical predictions given by Möller et al. using a macroscopic-microscopic model. It considerably influences the predictions of the abundances of the nuclides produced in the rp-process. (2) The current-model predictions are not consistent with the experimental assignments of the spins and parities for the proton drip-line nuclei142Ho and128Pm. However, the nuclear potential energy surface (PES) calculated by using a Woods-Saxon-Strutinsky method reproduced the experimental results. (3) The Alice code overestimated the production reaction cross sections of the studied 9 rare-earth nuclei by one order of magnitude or two, while HIVAP code overestimated them by one order of magnitude approximately.

Application of stratified implantation for silicon micro-strip detectors

In the fabrication of a 48 mm x48 mm silicon micro-strip nuclear radiation detector with 96 strips on each side, a perfect P-N junction cannot be formed consistently by the one-step implantation process, and thus over 50% of strips produced do not meet application requirements. However, the method of stratified implantation not only avoids the P region between the surface of wafers and the P+ region, but also overcomes the shadow effect. With the help of the stratified implantation process, a perfect functional P-N junction can be formed, and over 95% of strips meet application requirements.

NIEL studies on of double-sided silicon micro-strip detector

The methods of silicon detectors NIEL are given in this abstract and it also shows the result of proton NIEL for silicon.

Cross-talk studies on FPCB of double-sided silicon micro-strip detector

Double-sided silicon micro-strip detectors parameters and a test method and the results of cross-talk of FPCB are given in this abstract. In addition, the value of our detectors readout signal has little relation to FPCBs cross-talk.

Experimental study on β‐delayed proton decays in the rare‐earth region near drip line

The history of experimental study on β‐delayed proton decays in the rare‐earth region was simply reviewed. The physical results of the β‐delayed proton decays obtained at IMP, Lanzhou over the last 10 years were summarized, mainly including the first observation of 9 new β‐delayed proton precursors along the odd‐Z proton drip line and the new data for 2 waiting‐point nuclei in the rp‐process. The results were compared and discussed with different nuclear model calculations. Finally, the perspective in near future was briefly introduced.

β‐delayed proton decays in the rare‐earth region near drip line

The history of experimental study on β ‐delayed proton decays in the rare‐earth region was simply reviewed. The physical results of the β ‐delayed proton decays obtained at IMP, Lanzhou over the last 10 years were summarized, mainly including the first observation of 9 new β ‐delayed proton precursors along the odd‐Z proton drip line and the new data for 2 waiting‐point nuclei in the rp‐process. The results were compared and discussed with different nuclear model calculations. Finally, the perspective in near future was briefly introduced.