Showing 1–14 of 14 results for author: Ma, J B

A high-lying isomer in ^{92}Zr with lifetime modulated by the atomic charge states: a proposed approach for a nuclear gamma-ray laser

Authors: C. X. Jia, S. Guo, B. Ding, X. H. Zhou, C. X. Yuan, W. Hua J. G. Wang, S. W. Xu, C. M. Petrache, E. A. Lawrie, Y. B. Wu, Y. D. Fang, Y. H. Qiang, Y. Y. Yang, J. B. Ma, J. L. Chen, H. X. Chen, F. Fang, Y. H. Yu, B. F. Lv, F. F. Zeng, Q. B. Zeng, H. Huang, Z. H. Jia, W. Liang, W. Q. Zhang , et al. (23 additional authors not shown)

Abstract: The nuclides ^{92}Zr are produced and transported by using a radioactive beam line to a lowbackground detection station. After a flight time of about 1.14 μs, the ions are implanted into a carbon foil, and four γ rays deexciting the 8+ state in ^{92}Zr are observed in coincidence with the implantation signals within a few nanoseconds. We conjecture that there exists an isomer located slightly abov… ▽ More The nuclides ^{92}Zr are produced and transported by using a radioactive beam line to a lowbackground detection station. After a flight time of about 1.14 μs, the ions are implanted into a carbon foil, and four γ rays deexciting the 8+ state in ^{92}Zr are observed in coincidence with the implantation signals within a few nanoseconds. We conjecture that there exists an isomer located slightly above the 8^{+} state in ^{92}Zr. The isomeric lifetime in highly charged states is extended significantly due to the blocking of internal conversion decay channels, enabling its survival over the transportation. During the slowing-down process in the carbon foil, the ^{92}Zr ions capture electron and evolve toward neutral atoms, and consequently the lifetime is restored to a normal short value. Such a high-lying isomer depopulated by a low-energy transition may provide unique opportunity to develop nuclear γ laser. △ Less

Submitted 3 September, 2025; originally announced September 2025.

$t$+$t$ cluster states in $^{6}$He

Authors: W. H. Ma, D. Y. Tao, B. Zhou, J. S. Wang, Y. G. Ma, D. Q. Fang, W. B. He, Y. Y. Yang, J. B. Ma, S. L. Jin, P. Ma, J. X. Li, Y. S. Song, Q. Hu, Z. Bai, M. R. Huang, X. Q. Liu, Z. H. Gao, F. F. Duan, S. Y. Jin, S. W. Xu, G. M. Yu, T. F. Wang, Q. Wang

Abstract: The study of $t$+$t$ cluster states in $^{6}$He provides valuable insights into exotic nuclear structures and the behavior of fermionic cluster systems. This study shows rich cluster resonant state structures above the threshold, identified by experimental reconstruction and theoretical calculations. The excitation energy spectrum above the $t$+$t$ threshold in $^{6}$He is measured via the fragmen… ▽ More The study of $t$+$t$ cluster states in $^{6}$He provides valuable insights into exotic nuclear structures and the behavior of fermionic cluster systems. This study shows rich cluster resonant state structures above the threshold, identified by experimental reconstruction and theoretical calculations. The excitation energy spectrum above the $t$+$t$ threshold in $^{6}$He is measured via the fragmentation excitation process during the breakup reaction of $^{9}$Li on a $^{208}$Pb target at an incident energy of 32.7 MeV/nucleon. The resonant states are reconstructed from the final state coincident particles $t$+$t$ using the invariant mass method, while the non-resonant background is estimated using the event mixing method. Two states of energy level peaks at $13.9\pm0.3$ and $15.0\pm0.3$ MeV are observed. Microscopic cluster model calculations exploring the $t+t$ resonant states in $^6\mathrm{He}$ yield theoretical energy spectra which are then compared with the current experimental results. The calculated reduced width amplitudes (RWA) of the $t+t$ channels further confirm the clustering structure of the identified $t+t$ resonant states. △ Less

Submitted 12 January, 2026; v1 submitted 7 March, 2025; originally announced March 2025.

Comments: 9 pages, 5 figures,1 table

Property investigation for different wedge-shaped CsI(Tl)s

Authors: G. Li, J. L. Lou, Y. L. Ye, H. Hua, H. Wang, J. X. Han, W. Liu, S. W. Bai, Z. W. Tan, K. Ma, J. H. Chen, L. S. Yang, S. J. Wang, Z. Y. Hu, H. Z. Yu, H. Y. Zhu, B. L. Xia, Y. Jiang, Y. Liu, X. F. Yang, Q. T. Li, J. Y. Xu, J. S. Wang, Y. Y. Yang, J. B. Ma , et al. (10 additional authors not shown)

Abstract: Two types of wedge-shaped CsI(Tl)s were designed to be placed behind the annular double-sided silicon detectors (ADSSDs) to identify the light charged particles with the $ΔE-E$ method. The properties of CsI(Tl)s with different shapes and sizes, such as energy resolution, light output non-uniformity and particle identification capability, were compared by using a $α$-source and a radioactive beam o… ▽ More Two types of wedge-shaped CsI(Tl)s were designed to be placed behind the annular double-sided silicon detectors (ADSSDs) to identify the light charged particles with the $ΔE-E$ method. The properties of CsI(Tl)s with different shapes and sizes, such as energy resolution, light output non-uniformity and particle identification capability, were compared by using a $α$-source and a radioactive beam of $^{15}$C. The big-size CsI(Tl) was finally adopted to form the $ΔE-E$ telescope due to better properties. The property differences of these two types of CsI(Tl)s can be interpreted based on the Geant4 simulation results. △ Less

Submitted 2 March, 2021; originally announced March 2021.

Probing the nature of the conjectured low-spin wobbling bands in atomic nuclei

Authors: S. Guo, X. H. Zhou, C. M. Petrache, E. A. Lawrie, S. Mthembu, Y. D. Fang, H. Y. Wu, H. L. Wang, H. Y. Meng, G. S. Li, Y. H. Qiang, J. G. Wang, M. L. Liu, Y. Zheng, B. Ding, W. Q. Zhang, A. Rohilla, K. R. Mukhi, Y. Y. Yang, H. J. Ong, J. B. Ma, S. W. Xu, Z. Bai, H. L. Fan, J. F. Huang , et al. (6 additional authors not shown)

Abstract: Precession is a unique motion in which the orientation of the rotational axis of a rotating body is not fixed but moving, and it generally exists in the Universe from giant stars through tiny atomic nuclei. In principle, the precession of an atomic nuclide can be approximately described as wobbling motion, arising from the coupling of a rotation and a harmonic vibration. Recently, a number of wobb… ▽ More Precession is a unique motion in which the orientation of the rotational axis of a rotating body is not fixed but moving, and it generally exists in the Universe from giant stars through tiny atomic nuclei. In principle, the precession of an atomic nuclide can be approximately described as wobbling motion, arising from the coupling of a rotation and a harmonic vibration. Recently, a number of wobbling bands were reported at low spin, which violate the wobbling approximation that can be valid only at high spin. Here we explore the nature of the reported low-spin wobbling bands. Via a new experiment, we demonstrate that one such band in $^{187}$Au is generated by dominant single-particle excitation rather than by the excitation of a wobbling phonon. We point out that the imperfect research paradigm used previously would lead to unreliable identification of low-spin wobbling bands. Consequently, new experimental approaches should be developed to distinguish among the different excitation mechanisms that can give rise to the observed low-spin bands in odd-even nuclei. △ Less

Submitted 18 September, 2021; v1 submitted 29 November, 2020; originally announced November 2020.

Simultaneous measurement of beta-delayed proton and gamma emission of $^{26}$P for $^{25}$Al($p,γ$)$^{26}$Si reaction rate

Authors: P. F. Liang, L. J. Sun, J. Lee, S. Q. Hou, X. X. Xu, C. J. Lin, C. X. Yuan, J. J. He, Z. H. Li, J. S. Wang, D. X. Wang, H. Y. Wu, Y. Y. Yang, Y. H. Lam, P. Ma, F. F. Duan, Z. H. Gao, Q. Hu, Z. Bai, J. B. Ma, J. G. Wang, F. P. Zhong, C. G. Wu, D. W. Luo, Y. Jiang , et al. (31 additional authors not shown)

Abstract: $β$ decay of $^{26}$P was used to populate the astrophysically important $E_x=$5929.4(8) keV $J^π=3{^+}$ state of $^{26}$Si. Both $β… ▽ More $β$ decay of $^{26}$P was used to populate the astrophysically important $E_x=$5929.4(8) keV $J^π=3{^+}$ state of $^{26}$Si. Both $β$-delayed proton at 418(8) keV and gamma ray at 1742(2) keV emitted from this state were measured simultaneously for the first time with corresponding absolute intensities of 11.1(12)\% and 0.59(44)\%, respectively. Besides, shell model calculations with weakly bound effects were performed to investigate the decay properties of other resonant states and a spin-parity of $4^+$ rather than $0^+$ was favored for the $E_x=$5945.9(40) keV state. Combining the experimental results and theoretical calculations, $^{25}$Al($p,γ$)$^{26}$Si reaction rate in explosive hydrogen burning environments was calculated and compared with previous studies. △ Less

Submitted 25 September, 2019; originally announced September 2019.

Journal ref: Phys. Rev. C 101, 024305 (2020)

Beta-decay spectroscopy of $^{27}$S

Authors: L. J. Sun, X. X. Xu, S. Q. Hou, C. J. Lin, J. José, J. Lee, J. J. He, Z. H. Li, J. S. Wang, C. X. Yuan, D. X. Wang, H. Y. Wu, P. F. Liang, Y. Y. Yang, Y. H. Lam, P. Ma, F. F. Duan, Z. H. Gao, Q. Hu, Z. Bai, J. B. Ma, J. G. Wang, F. P. Zhong, C. G. Wu, D. W. Luo , et al. (33 additional authors not shown)

Abstract: Background: Beta-decay spectroscopy provides valuable nuclear physics input for thermonuclear reaction rates of astrophysical interest and stringent test for shell-model theories far from the stability line. Purpose: The available decay properties of proton drip-line nucleus $^{27}$S is insufficient to constrain the properties of the key resonance in $^{26}$Si$(p,γ)^{27}$P reaction rate and probe… ▽ More Background: Beta-decay spectroscopy provides valuable nuclear physics input for thermonuclear reaction rates of astrophysical interest and stringent test for shell-model theories far from the stability line. Purpose: The available decay properties of proton drip-line nucleus $^{27}$S is insufficient to constrain the properties of the key resonance in $^{26}$Si$(p,γ)^{27}$P reaction rate and probe the possible isospin asymmetry. The decay scheme of $^{27}$S is complicated and far from being understood, which has motivated but also presented challenges for our experiment. Method: The $^{27}$S ions were implanted into a double-sided silicon strip detector array surrounded by the high-purity germanium detectors, where the $β$-delayed protons and $γ$ rays were measured simultaneously. Results: The improved spectroscopic properties including the precise half-life of $^{27}$S, the excitation energies, $β$-decay branching ratios, log~$ft$ values, and $B$(GT) values for the states of $^{27}$P populated in the $β$ decay of $^{27}$S were measured and compared to the $^{27}$Mg mirror states and the shell-model calculations. The present work has expanded greatly on the previously established decay scheme of $^{27}$S. Conclusions: The precise proton-separation energy of $^{27}$P, the energy and the ratio between $γ$ and proton partial widths of the $3/2^+$ resonance were obtained, thereby determining the $^{26}$Si$(p,γ)^{27}$P reaction rate based mainly on experimental constraints. The first evidence for the observation of a large isospin asymmetry for the mirror decays of $^{27}$S and $^{27}$Na is also provided. The experimental spectroscopic information can be reproduced by the shell-model calculation taking the weakly bound effect of the proton $1s_{1/2}$ orbit into account. △ Less

Submitted 18 January, 2019; v1 submitted 9 September, 2018; originally announced September 2018.

Journal ref: Phys. Rev. C 99, 064312 (2019)

Experimentally well-constrained masses of $^{27}$P and $^{27}$S: Implications for studies of explosive binary systems

Authors: L. J. Sun, X. X. Xu, S. Q. Hou, C. J. Lin, J. José, J. Lee, J. J. He, Z. H. Li, J. S. Wang, C. X. Yuan, F. Herwig, J. Keegans, T. Budner, D. X. Wang, H. Y. Wu, P. F. Liang, Y. Y. Yang, Y. H. Lam, P. Ma, F. F. Duan, Z. H. Gao, Q. Hu, Z. Bai, J. B. Ma, J. G. Wang , et al. (36 additional authors not shown)

Abstract: The mass of $^{27}$P was predicted to impact the X-ray burst (XRB) model predictions of burst light curves and the composition of the burst ashes. To address the uncertainties and inconsistencies in the reported $^{27}$P masses in literature, a wealth of information has been extracted from the $β$-decay spectroscopy of the drip-line nucleus $^{27}$S. We determine the most precise mass excess of… ▽ More The mass of $^{27}$P was predicted to impact the X-ray burst (XRB) model predictions of burst light curves and the composition of the burst ashes. To address the uncertainties and inconsistencies in the reported $^{27}$P masses in literature, a wealth of information has been extracted from the $β$-decay spectroscopy of the drip-line nucleus $^{27}$S. We determine the most precise mass excess of $^{27}$P to date to be $-659(9)$~keV, which is 63~keV (2.3$σ$) higher than the AME2016 recommended value of $-722(26)$~keV. The experimentally unknown mass excess of $^{27}$S was estimated to be 17030(400)~keV in AME2016, and we constrain this mass to be 17678(77)~keV based on the measured $β$-delayed two-proton energy. In the temperature region of $(0.06-0.3)$~GK, the $^{26}$Si$(p,γ)^{27}$P reaction rate determined in this work is significantly lower than the rate recommended in the reaction rate libraries, up to two orders of magnitude around 0.1~GK. The impact of these newly determined masses and well-constrained rate on the modeling of the explosive astrophysical scenarios has been explored by hydrodynamic nova and post-processing XRB models. No substantial change was found in the nova contribution to the synthesis of galactic $^{26}$Al or in the XRB energy generation rate, but we found that the calculated abundances of $^{26}$Al and $^{26}$Si at the last stage of XRB are increased by a factor of 2.4. We also conclude that $^{27}$S is not a significant waiting point in the rapid proton capture process. △ Less

Submitted 13 October, 2019; v1 submitted 9 September, 2018; originally announced September 2018.

Observation of $^{6}$He+$t$ cluster states in $^{9}$Li

Authors: W. H. Ma, J. S. Wang, D. Patel, Y. Y. Yang, J. B. Ma, S. L. Jin, P. Ma, Q. Hu, Z. Bai, M. R. Huang, X. Q. Liu, Y. J. Zhou, J. Chen, Z. H. Gao, Q. Wang, J. Lubian, J. X. Li, T. F. Wang, S. Mukherjee, X. Y. Ju, Y. S. Yu, T. W. Wu, C. Ni, X. D. Jia, Q. B. Liu , et al. (3 additional authors not shown)

Abstract: $^{6}$He+$t$ cluster states of exited $^{9}$Li have been measured by 32.7 MeV/nucleon $^{9}$Li beams bombarding on $^{208}$Pb target. Two resonant states are clearly observed with the excitation energies at 9.8 MeV and 12.6 MeV and spin-parity of 3/2$^{-}$ and 7/2$^{-}$ respectively. These two states are considered to be members of K$^π$=1/2$^{-}… ▽ More $^{6}$He+$t$ cluster states of exited $^{9}$Li have been measured by 32.7 MeV/nucleon $^{9}$Li beams bombarding on $^{208}$Pb target. Two resonant states are clearly observed with the excitation energies at 9.8 MeV and 12.6 MeV and spin-parity of 3/2$^{-}$ and 7/2$^{-}$ respectively. These two states are considered to be members of K$^π$=1/2$^{-}$ band. The spin-parity of them are identified by the method of angular correlation analysis and verified by the continuum discretized coupled channels (CDCC) calculation, which agrees with the prediction of the generator coordinate method (GCM). A monopole matrix element about 4 fm$^{2}$ for the 3/2$^{-}$ state is extracted from the distorted wave Born approximation (DWBA) calculation. These results strongly support the feature of clustering structure of two neutron-rich clusters in the neutron-rich nucleus $^{9}$Li for the first time. △ Less

Submitted 5 January, 2018; v1 submitted 7 September, 2017; originally announced September 2017.

Journal ref: Phys. Rev. C 103, 061302 (2021)

Constraint on the Ground-state Mass of 21Al and Three-Nucleon Forces

Authors: X. Z. Teng, C. E. Teh, J. Lee, X. X. Xu, C. J. Lin, L. J. Sun, J. S. Wang, D. Q. Fang, S. Leblond, Z. H. Li, J. Li, N. R. Ma, J. B. Ma, H. L. Zang, P. Ma, S. L. Jin, M. R. Huang, Z. Bai, J. J. Liu, T. Lokotko, F. Yang, H. M. Jia, D. X. Wang, Y. Y. Yang, Z. G. Hu , et al. (2 additional authors not shown)

Abstract: Fragmentation cross section of $^{28}$Si + $^{9}$Be reaction at 75.8 MeV/u was analyzed for studying the decay mode of single-proton emission in $^{21}$Al (the proton-rich nucleus with neutron closed-shell of $N = 8$ and $T_z = -5/2$). With the comparison between the measured fragmentation cross section and the theoretical cross section produced by EPAX3.1a for the observed nuclei (i.e. $^{20}$Mg,… ▽ More Fragmentation cross section of $^{28}$Si + $^{9}$Be reaction at 75.8 MeV/u was analyzed for studying the decay mode of single-proton emission in $^{21}$Al (the proton-rich nucleus with neutron closed-shell of $N = 8$ and $T_z = -5/2$). With the comparison between the measured fragmentation cross section and the theoretical cross section produced by EPAX3.1a for the observed nuclei (i.e. $^{20}$Mg, $^{21}$Al and $^{22}$Si), the expected yield for a particle stable $^{21}$Al was estimated. With the exponential decay law, an upper limit of half-life of $13$ ns was determined. Using the single-proton penetration model, the upper limit of single-proton separation energy of $-105$ keV was deduced. This deduced mass limit agrees with the microscopic calculation based on nucleon-nucleon (NN) + three-nucleon (3N) forces in $sdf_{7/2}p_{3/2}$ valence space, which indicates the importance of 3N forces in $^{21}$Al. △ Less

Submitted 19 April, 2017; v1 submitted 11 April, 2017; originally announced April 2017.

Comments: 3 pages, 2 figures

The decay characteristic of $^{22}$Si and its ground-state mass significantly affected by three-nucleon forces

Authors: X. X. Xu, C. J. Lin, L. J. Sun, J. S. Wang, Y. H. Lam, J. Lee, D. Q. Fang, Z. H. Li, N. A. Smirnova, C. X. Yuan, L. Yang, Y. T. Wang, J. Li, N. R. Ma, K. Wang, H. L. Zang, H. W. Wang, C. Li, M. L. Liu, J. G. Wang, C. Z. Shi, M. W. Nie, X. F. Li, H. Li, J. B. Ma , et al. (20 additional authors not shown)

Abstract: The decay of the proton-rich nucleus $^{22}$Si was studied by a silicon array coupled with germanium clover detectors. Nine charged-particle groups are observed and most of them are recognized as $β$-delayed proton emission. A charged-particle group at 5600 keV is identified experimentally as $β$-delayed two-proton emission from the isobaric analog state of $^{22}$Al. Another charged-particle emis… ▽ More The decay of the proton-rich nucleus $^{22}$Si was studied by a silicon array coupled with germanium clover detectors. Nine charged-particle groups are observed and most of them are recognized as $β$-delayed proton emission. A charged-particle group at 5600 keV is identified experimentally as $β$-delayed two-proton emission from the isobaric analog state of $^{22}$Al. Another charged-particle emission without any $β$ particle at the low energy less than 300 keV is observed. The half-life of $^{22}$Si is determined as 27.5 (18) ms. The experimental results of $β$-decay of $^{22}$Si are compared and in nice agreement with shell-model calculations. The mass excess of the ground state of $^{22}$Si deduced from the experimental data shows that three-nucleon (3N) forces with repulsive contributions have significant effects on nuclei near the proton drip line. △ Less

Submitted 26 October, 2016; originally announced October 2016.

Comments: 6 pages, 4 figures

Beta-decay study of $T_z=-2$ proton-rich nucleus $^{20}$Mg

Authors: L. J. Sun, X. X. Xu, C. J. Lin, J. S. Wang, D. Q. Fang, Z. H. Li, Y. T. Wang, J. Li, L. Yang, N. R. Ma, K. Wang, H. L. Zang, H. W. Wang, C. Li, C. Z. Shi, M. W. Nie, X. F. Li, H. Li, J. B. Ma, P. Ma, S. L. Jin, M. R. Huang, Z. Bai, J. G. Wang, F. Yang , et al. (10 additional authors not shown)

Abstract: The $β$ decay of the drip-line nucleus $^{20}$Mg gives important information on resonances in $^{20}$Na, which are relevant for the astrophysical $rp$-process. A detailed $β$ decay spectroscopic study of $^{20}$Mg was performed by a continuous-implantation method. A detection system was specially developed for charged-particle decay studies, giving improved spectroscopic information including the… ▽ More The $β$ decay of the drip-line nucleus $^{20}$Mg gives important information on resonances in $^{20}$Na, which are relevant for the astrophysical $rp$-process. A detailed $β$ decay spectroscopic study of $^{20}$Mg was performed by a continuous-implantation method. A detection system was specially developed for charged-particle decay studies, giving improved spectroscopic information including the half-life of $^{20}$Mg, the excitation energies, the branching ratios, and the log $ft$ values for the states in $^{20}$Na populated in the $β$ decay of $^{20}$Mg. A new proton branch was observed and the corresponding excited state in $^{20}$Na was proposed. The large isospin asymmetry for the mirror decays of $^{20}$Mg and $^{20}$O was reproduced, as well. However, no conclusive conclusion can be draw about the astrophysically interesting 2645~keV resonance in $^{20}$Na due to the limited statistics. △ Less

Submitted 10 October, 2016; originally announced October 2016.

Journal ref: Phys. Rev. C 95, 014314 (2017)

New measurement of the excited states in $^{11}$B via the elastic resonance scattering of $^{10}$Be + p

Authors: Y. D. Liu, H. W. Wang, Y. G. Ma, X. G. Cao, G. Q. Zhang, D. Q. Fang, M. Lyu, W. B. He, Z. T. Dai, C. Li, C. L. Zhou, S. Q. Ye, C. Tao, J. Wang, S. Kumar, J. L. Han, Y. Y. Yang, P. Ma, J. B. Ma, S. L. Jin, Z. Bai, L. Jin, D. Yan, J. S. Wang

Abstract: The elastic resonance scattering protons decayed from $^{11}$B to the ground state of $^{10}$Be were measured using the thick-target technique in inverse kinematics at the Heavy Ion Research Facility in Lanzhou (HIRFL). The obtained excitation functions were well described by a multichannel R-matrix procedure under the kinematics process assumption of resonant elastic scattering. The excitation en… ▽ More The elastic resonance scattering protons decayed from $^{11}$B to the ground state of $^{10}$Be were measured using the thick-target technique in inverse kinematics at the Heavy Ion Research Facility in Lanzhou (HIRFL). The obtained excitation functions were well described by a multichannel R-matrix procedure under the kinematics process assumption of resonant elastic scattering. The excitation energy of the resonant states ranges from 13.0 to 17.0 MeV, and their resonant parameters such as the resonant energy E$_{x}$, the spin-parity J$^π$, and the proton-decay partial width $Γ_p$ were determined from R-matrix fits to the data. Two of these states around E$_{x}$ = 14.55 MeV [J$^π$ = (3/2$^+$, 5/2$^+$), $Γ_p$ = 475 $\pm$ 80 keV] and E$_{x}$ = 14.74 MeV [J$^π$ = 3/2$^-$, $Γ_p$ = 830 $\pm$ 145 keV], and a probably populated state at E$_x$ = 16.18 MeV [J$^π$ =(1/2$^-$, 3/2$^-$), $Γ_p$ $<$ 60 keV], are respectively assigned to the well-known states in $^{11}$B at 14.34 MeV, 15.29 MeV, and 16.43 MeV. The isospin of these three states were previously determined to be T = 3/2, but discrepancies exist in widths and energies due to the current counting statistics and energy resolution. We have compared these states with previous measurements, and the observation of the possibly populated resonance is discussed. △ Less

Submitted 18 March, 2015; originally announced March 2015.

Comments: 7 pages, 2 tables, 7 figures; Physical Review C (2015) accepted

Journal ref: Phys. Rev. C 91, 044302 (2015)

The performance of a double sided silicon strip detector as a transmission detector for heavy ions

Authors: J L Han, J B Ma, X G Cao, Q Wang, J S Wang, Y Y Yang, P Ma, M R Huang, S L Jin, X J Rong, Z Bai, F Fu, Q Hu, R F Chen, S W Xu, J B Chen, L Jin, Y Li, M H Zhao, H S Xu

Abstract: The performance of a double sided silicon strip detector (DSSSD), used for position and energy detection of heavy ions, is reported. The analysis shows that the incomplete charge collection (ICC) and charge sharing (CS) effects of the DSSSD give rise to a loss of energy resolution, however the position information is recorded without ambiguity. Representations of ICC/CS events in the energy spectr… ▽ More The performance of a double sided silicon strip detector (DSSSD), used for position and energy detection of heavy ions, is reported. The analysis shows that the incomplete charge collection (ICC) and charge sharing (CS) effects of the DSSSD give rise to a loss of energy resolution, however the position information is recorded without ambiguity. Representations of ICC/CS events in the energy spectra are shown and their origins are confirmed by correlation analysis of the spectra from both junction side and ohmic side of the DSSSD. △ Less

Submitted 15 July, 2013; originally announced July 2013.

Investigation of excited states in $^{18}$Ne via resonant elastic scattering of $^{17}$F+p and its astrophysical implication in the stellar reaction of $^{14}$O($α$,$p$)$^{17}$F

Authors: J. Hu, J. J. He, S. W. Xu, Z. Q. Chen, X. Y. Zhang, J. S. Wang, X. Q. Yu, L. Li, L. Y. Zhang, Y. Y. Yang, P. Ma, X. H. Zhang, Z. G. Hu, Z. Y. Guo, X. Xu, X. H. Yuan, W. Lu, Y. H. Yu, Y. D. Zang, S. W. Tang, R. P. Ye, J. D. Chen, S. L. Jin, C. M. Du, S. T. Wang , et al. (13 additional authors not shown)

Abstract: Properties of proton resonances in $^{18}$Ne have been investigated efficiently by utilizing a technique of proton resonant elastic scattering with a $^{17}$F radioactive ion (RI) beam and a thick proton target. A 4.22~MeV/nucleon $^{17}$F RI beam was produced via a projectile-fragmentation reaction, and subsequently separated by a Radioactive Ion Beam Line in Lanzhou ({\tt RIBLL}). Energy spectra… ▽ More Properties of proton resonances in $^{18}$Ne have been investigated efficiently by utilizing a technique of proton resonant elastic scattering with a $^{17}$F radioactive ion (RI) beam and a thick proton target. A 4.22~MeV/nucleon $^{17}$F RI beam was produced via a projectile-fragmentation reaction, and subsequently separated by a Radioactive Ion Beam Line in Lanzhou ({\tt RIBLL}). Energy spectra of the recoiled protons were measured by two sets of $Δ$E-E silicon telescope at center-of-mass scattering angles of $θ_{c.m.}$$\approx$175${^\circ}$$\pm$5${^\circ}$, $θ_{c.m.}$$\approx$152${^\circ}$$\pm$8${^\circ}$, respectively. Several proton resonances in $^{18}$Ne were observed, and their resonant parameters have been determined by an $R$-matrix analysis of the differential cross sections in combination with the previous results. The resonant parameters are related to the reaction-rate calculation of the stellar $^{14}$O($α$,$p$)$^{17}$F reaction, which was thought to be the breakout reaction from the hot CNO cycles into the $rp$-process in x-ray bursters. Here, $J^π$=(3$^-$, 2$^-$) are tentatively assigned to the 6.15-MeV state which was thought the key 1$^-$ state previously. In addition, a doublet structure at 7.05 MeV are tentatively identified, and its contribution to the resonant reaction rate of $^{14}$O($α$,$p$)$^{17}$F could be enhanced by at least factors of about 4$\sim$6 in comparison with the previous estimation involving only a singlet. The present calculated resonant rates are much larger than those previous values, and it may imply that this breakout reaction could play a crucial role under x-ray bursters conditions. △ Less

Submitted 7 September, 2010; originally announced September 2010.

Comments: 8 figures, 2 tables