One-neutron stripping process in the^(209)Bi(^(6)Li,^(5)Li)^(210)Bi*reaction reaction

One-neutron stripping process between^(6)Li and^(209)Bi was studied at 28,30,and 34 MeV using the in-beamγ-ray spectroscopy method.Theγ-γcoincident analysis clearly identified twoγ-rays feeding the ground and long-lived isomeric states,which were employed to determine the cross section.The one-neutron stripping cross sections were similar to the cross sections of complete fusion in the^(6)Li+^(209)Bi system,but the one-neutron stripping cross sections decreased more gradually at the sub-barrier region.A coupled-reaction-channel calculation was performed to study the detailed reaction mechanism of the one-neutron stripping process in^(6)Li.The calculations indicated that the first excited state of 5 Li is critical in the actual one-neutron transfer mechanism,and the valence proton of 209Bi can be excited to the low-lying excited state in(^(6)Li,^(5)Li)reaction,unlike in the(d,p)reaction.

A detector setup for the measurement of angular distribution of heavy-ion elastic scattering with low energy on RIBLL

A detector setup for the measurement of angular distribution of heavy-ion elastic scattering at energies around Coulomb barrier on the radioactive ion beam line in Lanzhou at the heavy-ion research facility in Lanzhou is designed.The beam profile and the scattering angles on the target are deduced by two parallel plate avalanche counters,and four sets of detector telescopes(including doublesided silicon strip detectors) are placed systematically with the beam line,incorporating with Monte Carlo simulations.The data of ^(16)O on ^(89)Y target were analyzed to compare with the simulation results.It is found that the simulated distribution is agreeable with the experimental data.By assuming the pure Rutherford scattering at small scattering angles,the angular distribution of elastic scattering of^(16)O+^(89)Y at low energies can be reasonably obtained.It indicates that this set of detector setup can be used for the measurement of angular distributions of heavy-ion elastic scattering at energies around Coulomb barrier.

The effects of beam drifts on elastic scattering measured by the large solid-angle covered detector array

A new detector array characterized by compact structure and large solid-angle coverage was designed for radioactive ion beam(RIB)experiments and measuring multi-particle correlations.A Monte Carlo simulation was performed to explore the effects of beam drifts in different directions and distances on the angular distribution of the Rutherford scattering,as measured by the detector array.The results indicate that when the beam drift distance is less than 2.0 mm,the symmetry of the detector array can maintain a count error of less than 5%.This confirms the property of the detector array for RIB experiments.Furthermore,the simulation was validated through the elastic scattering angular distributions of 6;7 Li measured by the detector array in 6;7Li t209 Bi experiments at different energies.

Attenuation coefficients of gamma and X-rays passing through six materials

The aim of this study was to determine the attenuation of gamma and X-rays with different energies caused by passage through different materials.To this end,different materials with a range of atomic numbers were chosen to measure gamma and X-ray attenuation coefficients and to explore the mechanisms of interaction of gamma and X-rays with matter of various kinds.It is shown that the attenuation coefficients first decrease and then increase with increase in the radiation(photon)energy.The attenuation of gamma and X-rays passing through materials with high atomic number is greater than that in materials with low atomic number.The attenuation minimum is related to the atomic number of the irradiated materials.The larger the atomic number is,the lower the energy corresponding to attenuation minimum is.Photoelectric and Compton effects are the main processes when gamma rays pass through individual materials with high and low atomic numbers,respectively.Therefore,for radiotherapy and radiation protection,different methods should be considered and selected for the use of gamma and X-rays of different energies for use in different materials.

Evaluation of CdZnTe spectrometer performance in measuring energy spectra during interventional radiology procedure

Interventional radiology has been beneficial for patients for over 30 years of age with the combination of diagnostic and therapeutic methods. The radiation affecting occupationally exposed workers should be evaluated by means of the energy spectra and flux of X-rays in the treatment room. The present study aims to obtain the energy spectra of interventional procedures and study the capability of some detectors to evaluate the dose in interventional procedures. These measurements were taken by silicon-drift, CdTe, and CdZnTe detectors. The energy spectra were corrected by the energy-response curve of each detector. The energy-response curves of silicon-drift and CdTe detectors provided by the manufacturers specification were used. The energy response of the CdZnTe detector was measured by 133Ba and 152Eu γ sources. The experimental data were compared with the simulation results, and their perfect agreement provides a way to correct the energy or dose response, which can be used for the personal dosimeter developed by our group. Moreover, the measured energy spectra can be used in individual radiation protection. The present study shows that the CdZnTe detector is a good candidate detector in interventional procedures.

Dynamic energy spectrum and energy deposition in solid target by intense pulsed ion beams

A method for analyzing the dynamic energy spectrum of intense pulsed ion beam(IPIB) was proposed.Its influence on beam energy deposition in metal target was studied with IPIB produced by two types of magnetically insulated diodes(MID).The emission of IPIB was described with space charge limitation model,and the dynamic energy spectrum was further analyzed with time-of-flight method.IPIBs generated by pulsed accelerators of BIPPAB-450(active MID) and TEMP-4M(passive MID) were studied.The dynamic energy spectrum was used to deduce the power density distribution of IPIB in the target with Monte Carlo simulation and infrared imaging diagnostics.The effect on the distribution and evolution of thermal field induced by the characteristics of IPIB dynamic energy spectrum was discussed.

Energy calibration of HPGe detector using the high-energy characteristic γ rays in 13C formed in 6Li + 12C reaction

An 6 Li+89Y experiment was conducted at the Laboratori Nazinali di Legnaro,INFN,Italy.The 550μg/cm^2 thick^89Y target was backed on a 340μg/cm^2 thick 12C foil.The severalγrays in the experiment with energies higher than 3000 keV can most likely be ascribed to the transitions in the 13C nuclei,which can be formed through various interactions between the 6 Li beam and the 12C foil.The high-energy properties ofγrays in 13C are employed for energy calibrating HPGe detectors,especially for the>3000 keV region,which is impossible to reach by common standard sources(152Eu,133Ba,etc.).Furthermore,γ-γand particle-γcoincidence measurements were performed to investigate the formation of 13C.

Investigating the level structure of ^(206)Rn:evolution from seniority regime to collective dynamics

Excited states of ^(206)Rn have been examined via the 197 Au(^(14)N,5n)^(206)Rn fusion reaction at a beam energy of 78 MeV.A number of transitions and levels are identified by the γ-γ coincidence measurement,further enriching the level scheme of ^(206)Rn.The fullconfiguration shell model and nucleon-pair approximation(NPA)were utilized to investigate the single-particle configurations and seniority structures in ^(206)Rn.The results of these two calculations suggest that 2_(1)^(+) and 4_(1)^(+) states exhibit only a 50%component of a seniority-two state associated with a broken neutron pair.The collectivity of these two states primarily arises from configuration mixing due to residual proton-neutron interactions.Furthermore,6_(1)^(+) and 8_(1)^(+) states are predominantly characterized by a seniority-two state marked by a broken proton pair.

Low-lying states of 92,93Nb excited in the reactions induced by the weakly-bound nucleus 6Li near the Coulomb barrier

Excited states of odd-odd nucleus 92Nb and odd-A nucleus 93Nb were populated in the 6 Li+ 89 Y reaction with an incident energy of 34 MeV. The processes that produce 92,93Nb and can be measured by a combination of light charged particle and gamma ray measurements are discussed. Twenty new transitions are observed and eight new levels are constructed in 92Nb, and in addition two new transitions are added to the level scheme of 93Nb. Using shell2 model calculations, the low-lying structure of 9 Nb is investigated and compared with the experimental results.

Angular distribution measurement for ^12C fragmentation via ^12C ＋ ^12C scattering at 100 MeV/u

The angular distributions and energy spectra of 11B, 10B, and 9Be fragments of 12C in the angular range from 1.0° to 7.5° at 100 MeV/u were obtained via 12C ＋ 12C scattering. Detailed comparisons are presented between the experimental data and the modified antisymmetrized molecular dynamics （AMD-FM）, binary intranuclear cascade model （BIC） and Liège intranuclear cascade model （INCL＋＋）. The experimental angular distributions and energy spectra are well reproduced by the AMD-FM calculations but fail to be reproduced by the physical models installed in the Geant4 program, including the BIC and INCL＋＋ models.

Relative probabilities of breakup channels in reactions of^(6.7)Li with^(209)Biat energies around and above the Coulomb barrier

Coincidence measurements of breakup fragments in reactions of^(6.7)with^(209)Bi at energies around and above the Coulomb barrier were carried out using a large solid-angle covered detector array.Through the Q values along with the relative energies of the breakup fragments,different breakup components(prompt breakups and delayed breakups)and different breakup modes(α+t,α+d,α+p,andα+α)are distinguished.A new breakup mode,α+t,is observed in^(6)Li-induced reactions at energies above the Coulomb barrier.Correlations between breakup modes and breakup components as well as their variations with the incident energy are investigated.The results will help us better understand the breakup effects of weakly bound nuclei on the suppression of a complete fusion,particularly for the above-barrier energies.

Performance study of trial M-THGEM

Background M-THGEM is a new type of electron multiplier,which is developed with a high gain,good stability and uniformity based on THGEM.With the successful application of small area M-THGEM,the large-area M-THGEM is proposed based on large-volume gas detector.Purpose The production of large-area M-THGEM is difficult compared with the small one with more holes and more stable instruments.To meet the requirements of large-area gas detectors,the performances of the large-area M-THGEM need to be measured and researched,which will provide a guidance on the process and design of the M-THGEM.Methods The M-THGEM membrane was loaded into a chamber to complete the test under the conditions of 55Fe/X-ray source(5.9 keV)and working gas Ar∶iC4H10=97∶3.The performance of gain,energy resolution,uniformity and long-term stability can be tested.Results Based on the small area M-THGEM,the research and design of large-area M-THGEM with 200×200 mm^(2)were finished.The basic performances were measured.The results show that the gain with the working gas of Ar∶iC_(4)H_(10)=97∶3 can reach to 6×10^(3),and the energy resolution of the^(55)Fe/X-ray source(5.9 keV)reaches 29.4%with a good gain uniformity and stability.Conclusion At present,the production and measurement of the large-area M-THGEM has been finished.The M-THGEM of 200×200 mm^(2)shows a good performance,which will provide many references for the future design.

The angular distributions of elastic scattering of^12,13C+Zr

To obtain the neutron spectroscopic amplitudes for 90-96Zx overlaps experimental data of elastic scatter-ing with small experimental errors and precise optical potentals were anary exin othe hiohpyecision o3D magneticangular distributions of^12,^13C+^AZr(A=90,91,92,94,96)were measured using the high-precision Q3D magnetic spectrometer in the Tandem accelerator.The Sao Paulo potential was used for the optical potential.The optical mod-el and coupled channel calculations were compared with the experimental data.The theoretical results were found tobe very close to the experimental data.In addition,the possible effects of the couplings to the inelastic channels of the^AZr targets and 12,13^C projectiles on the elastic scattering were studied.It was observed that the couplings to the in-elastic channels of the^12,^13C projectiles could improve the agreement with the experimental data,while the inelasticcouplings to the target states are of minor importance.The effect of the one-neutron stripping in the^13C+^AZr elasticscattering was also studied.The one-neutron stripping channel in^13C+^AZr was found to be not relevant and did notaffect the elastic scattering angular distributions.Our results also show that in the reactions with the considered zir-conium isotopes,the presence of the extra neutron in^13C does not influence the reaction mechanism,which is gov-erned by the collective excitation of the^12C core.