1996 Vol. 20, No. S1
Display Method:|
Abstract:
A new isotope175Er was synthesized for the first time by the176Yb(n,2p)175Er reaction in irradiation of natural metal ytterbium targets with 14 MeV neutrons. The activities of175Er were observed byγ(X) ray spectroscopy. Eight newγrays of 76.5, 120.9, 123.7, 128.5,227.3,234.0,281.4, and 1167.5 keV with half-life of 1.2±0.3 min were found and assigned to theβdecay of175Er. A partial decay scheme of175Er was proposed.
A new isotope175Er was synthesized for the first time by the176Yb(n,2p)175Er reaction in irradiation of natural metal ytterbium targets with 14 MeV neutrons. The activities of175Er were observed byγ(X) ray spectroscopy. Eight newγrays of 76.5, 120.9, 123.7, 128.5,227.3,234.0,281.4, and 1167.5 keV with half-life of 1.2±0.3 min were found and assigned to theβdecay of175Er. A partial decay scheme of175Er was proposed.
Abstract:
Particle-particle correlation functions have been measured for40Ar+197Au collisions atE/A=25 MeV. Emission time of light particles has been extracted from correlation functions using the three-body trajectory model. The average emission time varies with the energy of particles. It decreases from about 300 fm/cfor low energy particles to about 100 fm/cfor energetic particles.
Particle-particle correlation functions have been measured for40Ar+197Au collisions atE/A=25 MeV. Emission time of light particles has been extracted from correlation functions using the three-body trajectory model. The average emission time varies with the energy of particles. It decreases from about 300 fm/cfor low energy particles to about 100 fm/cfor energetic particles.
Abstract:
The yields of known hafnium isotopes produced in 6.3-24.6 MeV/nucleon40Ar+natW reactions were determined byγ-ray spectroscopy following chemical separation. The excitation function, theFWvalue, and isotope distributions were obtained. It was deduced that using HIRFL energy heavy ions to synthesize new neutron-rich nuclides in theA> 170 region is possible. Using thick target or multi-thin target can obviously increase the yield of a new neutron-rich nuclide. Increasing projectile energy is not always helpful to synthesize a new neutron-rich nuclide.
The yields of known hafnium isotopes produced in 6.3-24.6 MeV/nucleon40Ar+natW reactions were determined byγ-ray spectroscopy following chemical separation. The excitation function, theFWvalue, and isotope distributions were obtained. It was deduced that using HIRFL energy heavy ions to synthesize new neutron-rich nuclides in theA> 170 region is possible. Using thick target or multi-thin target can obviously increase the yield of a new neutron-rich nuclide. Increasing projectile energy is not always helpful to synthesize a new neutron-rich nuclide.
Abstract:
By using experimental data obtained from the measurement ofβ-delayed proton decay of65Se produced in the40Ga(28Si,3n) reaction, the absolute detection efficiency of particle telescope for rotating radioactive source was fitted and calculated. The half-life of65Se was thus accurately determined to be 9.6-4.1+5.3ms and itsβ-delayed proton energy of65Se was 3.70±0.08MeV. The partial decay scheme of65Seβ-delayed proton decay was revised.
By using experimental data obtained from the measurement ofβ-delayed proton decay of65Se produced in the40Ga(28Si,3n) reaction, the absolute detection efficiency of particle telescope for rotating radioactive source was fitted and calculated. The half-life of65Se was thus accurately determined to be 9.6-4.1+5.3ms and itsβ-delayed proton energy of65Se was 3.70±0.08MeV. The partial decay scheme of65Seβ-delayed proton decay was revised.
Abstract:
A two-dimensional position sensitive multi-stage detection system with a wide dynamic range for a heavy ion reaction is described in this paper. It consists of four parts:a longitudinal electric field gas filled Ionization Chamber (IC), a Position Sensitive Silicon Detector (PSSD) (45 mm×45 mm, 400μm), a large area PIN Silicon Photodiode (SPD) (48 mm×48 mm, 300μm),and a 16 element CsI(Tl) scintillation detector array. The energy resolutions for IC and PSSD tested with a source241Am(5.486 MeV) are 3% and 2.6%, respectively. The energy dynamic range forαparticle detection is about 2-130 MeV, and the fragments withZValues fromZ=2 toZ=21 are identified in the reaction of 25 MeV/u40Ar+115In. TheZresolving power isZ/△Z≈ 44.5 (FWHM) forZ=18. The position resolution of PSSD is 0.86±0.03 mm (FWHM).
A two-dimensional position sensitive multi-stage detection system with a wide dynamic range for a heavy ion reaction is described in this paper. It consists of four parts:a longitudinal electric field gas filled Ionization Chamber (IC), a Position Sensitive Silicon Detector (PSSD) (45 mm×45 mm, 400μm), a large area PIN Silicon Photodiode (SPD) (48 mm×48 mm, 300μm),and a 16 element CsI(Tl) scintillation detector array. The energy resolutions for IC and PSSD tested with a source241Am(5.486 MeV) are 3% and 2.6%, respectively. The energy dynamic range forαparticle detection is about 2-130 MeV, and the fragments withZValues fromZ=2 toZ=21 are identified in the reaction of 25 MeV/u40Ar+115In. TheZresolving power isZ/△Z≈ 44.5 (FWHM) forZ=18. The position resolution of PSSD is 0.86±0.03 mm (FWHM).
Abstract:
A new neutron-deficient isotope235Am was synthesized in the reaction of238Pu(p,4n)235Am by using 35 MeV proton bombarding238Pu target. The products were transported by the He-jet system. The Am was separated from the reaction products using the radiochemistry method. Theγ-ray of235Pu and X-ray of Np following the EC decay of235Am were observed. Based on the growth-decay curve of X-ray of Np and the X-γcoincidence measurements, the synthesis of235Am was confirmed for the first time. The measured half-life of235Am is 15 ±5 min.
A new neutron-deficient isotope235Am was synthesized in the reaction of238Pu(p,4n)235Am by using 35 MeV proton bombarding238Pu target. The products were transported by the He-jet system. The Am was separated from the reaction products using the radiochemistry method. Theγ-ray of235Pu and X-ray of Np following the EC decay of235Am were observed. Based on the growth-decay curve of X-ray of Np and the X-γcoincidence measurements, the synthesis of235Am was confirmed for the first time. The measured half-life of235Am is 15 ±5 min.
Abstract:
We construct explicitly the two-dimensional cyclic representation of quantum algebraUq(sl(2)) withq=iandzcentral extension. The representation is irreducible and we write down explicitly the Clebsch-Gordan coefficients and the intertwiner of tensor representations in different orders. This intertwiner turns out to be an 8-vertexR-matrix that satisfies the free-Fermion condition and therefore gives an integrable model.
We construct explicitly the two-dimensional cyclic representation of quantum algebraUq(sl(2)) withq=iandzcentral extension. The representation is irreducible and we write down explicitly the Clebsch-Gordan coefficients and the intertwiner of tensor representations in different orders. This intertwiner turns out to be an 8-vertexR-matrix that satisfies the free-Fermion condition and therefore gives an integrable model.