A knockout reaction experiment was carried out by using the 6He beam at 82.5 MeV/nucleon impinging on CH2 and C targets. The a core fragments at forward angles were detected in coincidence with the recoiled protons at...A knockout reaction experiment was carried out by using the 6He beam at 82.5 MeV/nucleon impinging on CH2 and C targets. The a core fragments at forward angles were detected in coincidence with the recoiled protons at larger angles. From this exclusive measure- ment the valence nucleon knockout mechanism and the core knockout mechanism are separated. This study provides a basis for the exclusive spectroscopic investigation of the exotic nuclei.展开更多
The latest progress made in the field of radioactive ion beam physics is outlined and the key problems still under investigation are indicated. The focal points are the limit of nuclear existence, shell evolution and ...The latest progress made in the field of radioactive ion beam physics is outlined and the key problems still under investigation are indicated. The focal points are the limit of nuclear existence, shell evolution and new magic numbers, halo and cluster structures, new excitation modes, and strong coupling between reaction channels. This field is still at a starting phase and much more new outcomes are foreseen.展开更多
The β-delayed neutron and γ energy spectra taken from the decay of neutron-rich nucleus ^21N were measured by using the β - γ and β - n coincidence detection method. Thirteen new neutron groups ranging from 0.28 ...The β-delayed neutron and γ energy spectra taken from the decay of neutron-rich nucleus ^21N were measured by using the β - γ and β - n coincidence detection method. Thirteen new neutron groups ranging from 0.28 MeV to 4.98 MeV and with a total branching ratio of 88.7±4.2% were observed and presented. One γ transition with an energy of 1222 keV emitted from the excited state of ^21O and four γ transitions with energies of 1674, 2397, 2780, and 3175keV emitted from the excited states of ^20O were identified in the β decay chain of ^21N. The β decay half-life for ^21N is determined to be 82.9±1.9ms. The uncertainty of half-life is much smaller than the previous result.展开更多
Breakup reactions of the double borromean nucleus ^(8)He were measured at 82.3 MeV/u on CH2 and C targets.The coincident detection of two decaying neutrons and the high performance for neutron cross talk rejection are...Breakup reactions of the double borromean nucleus ^(8)He were measured at 82.3 MeV/u on CH2 and C targets.The coincident detection of two decaying neutrons and the high performance for neutron cross talk rejection are realized in this experiment.The relative energy spectrum for ^(8)He was reconstructed with good statistics.The spectrum exhibits a structure of two resonant peaks,one at an excitation energy of about 3.0 and the other at about 4.14 MeV,respectively.Substantially larger cross section for the first resonance is observed in comparison to the results reported previously.展开更多
An experiment for knockout reaction induced by SHe beam at 82.5 MeV/nucleon on CH2 and C targets was carried out. The 6He and 4He core fragments at forward angles and the recoiled protons at large angles were detected...An experiment for knockout reaction induced by SHe beam at 82.5 MeV/nucleon on CH2 and C targets was carried out. The 6He and 4He core fragments at forward angles and the recoiled protons at large angles were detected coincidently. From this exclusive measurement the valence nucleon knockout mechanism and the core knockout mechanism are separated, which can be applied to the exclusive spectroscopic study on the structure of exotic nuclei.展开更多
基金supported by the National Basic Research Program of China (No. 2007CB815002)National Natural Science Foundation of China(Nos. 11035001, 10775003, 10827505, 10821140159)
文摘A knockout reaction experiment was carried out by using the 6He beam at 82.5 MeV/nucleon impinging on CH2 and C targets. The a core fragments at forward angles were detected in coincidence with the recoiled protons at larger angles. From this exclusive measure- ment the valence nucleon knockout mechanism and the core knockout mechanism are separated. This study provides a basis for the exclusive spectroscopic investigation of the exotic nuclei.
基金supported by National Basic Research Program of China (No.2007CB815002)National Natural Science Foundation of China(Nos.11035001,10775003,10827505,10821140159)
文摘The latest progress made in the field of radioactive ion beam physics is outlined and the key problems still under investigation are indicated. The focal points are the limit of nuclear existence, shell evolution and new magic numbers, halo and cluster structures, new excitation modes, and strong coupling between reaction channels. This field is still at a starting phase and much more new outcomes are foreseen.
基金Supported by the National Basic Research Programme of China under Grant Nos 2007CB815000 and 2005CB724800, the National Natural Science Foundation of China under Grant Nos 10775003,10475004, 10405001, 10221003 and J0730316.
文摘The β-delayed neutron and γ energy spectra taken from the decay of neutron-rich nucleus ^21N were measured by using the β - γ and β - n coincidence detection method. Thirteen new neutron groups ranging from 0.28 MeV to 4.98 MeV and with a total branching ratio of 88.7±4.2% were observed and presented. One γ transition with an energy of 1222 keV emitted from the excited state of ^21O and four γ transitions with energies of 1674, 2397, 2780, and 3175keV emitted from the excited states of ^20O were identified in the β decay chain of ^21N. The β decay half-life for ^21N is determined to be 82.9±1.9ms. The uncertainty of half-life is much smaller than the previous result.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11035001,10975006 and J1103206the National Basic Research Program of China under Grant No 2007CB815002.
文摘Breakup reactions of the double borromean nucleus ^(8)He were measured at 82.3 MeV/u on CH2 and C targets.The coincident detection of two decaying neutrons and the high performance for neutron cross talk rejection are realized in this experiment.The relative energy spectrum for ^(8)He was reconstructed with good statistics.The spectrum exhibits a structure of two resonant peaks,one at an excitation energy of about 3.0 and the other at about 4.14 MeV,respectively.Substantially larger cross section for the first resonance is observed in comparison to the results reported previously.
基金supported by the National Basic Research Program of China (No. 2007CB815002)National Natural Science Foundation of China(Nos. 11035001, 10775003, 10827505, 10821140159)
文摘An experiment for knockout reaction induced by SHe beam at 82.5 MeV/nucleon on CH2 and C targets was carried out. The 6He and 4He core fragments at forward angles and the recoiled protons at large angles were detected coincidently. From this exclusive measurement the valence nucleon knockout mechanism and the core knockout mechanism are separated, which can be applied to the exclusive spectroscopic study on the structure of exotic nuclei.
