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1.
2.
The masses of over sixty short-lived Rb, Sr, Cs, Ba, Fr and Ra isotopes have been measured at the on-line mass separator ISOLDE at CERN/Geneva by determination of their cyclotron frequency in the tandem Penning trap system ISOLTRAP. Resolving powers exceedingm/m(FWHM)=106 and accuracies of typically m/m=10–7 could be achieved. ISOLTRAP can also act as an isomer separator, as proven for the cases of84Rb and78Rb.  相似文献   

3.
First direct mass measurements on rare earth isotopes around 146Gd have been performed with the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. More than 40 isotopes of the elements Pr, Nd, Pm, Sm, Eu, Dy and Ho have been measured with an accuracy of typically 1 × 10-7. In the case of 141Sm isomeric and ground state (ΔE = 175 keV) were resolved. Since isobaric contaminations are present in the ISOLDE beam, these measurements on rare earth isotopes became only possible after the installation of a new cooler trap which acts an isobar separator. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

4.
Isotope shifts of the neutron-deficient thallium isotopes were measured on-line at the UNISOR mass separator. Spectroscopy was carried out using collinear fast beam laser spectroscopy in neutral thallium. The changes of the mean square charge radii were derived from the measurements. The changes in charge radii of the I=7 isotopes, including the newly measured188Tl, are compared to the results in mercury and lead.  相似文献   

5.
The FRS-ESR facility at GSI provides one of the most efficient methods for direct mass measurements. In the present experiment, exotic nuclei were produced via fragmentation of 152Sm projectiles in a thick beryllium target at 500-600 MeV/u, separated in-flight with the fragment separator FRS, and injected into the storage-cooler ring ESR. Time-resolved Schottky Mass Spectrometry was applied for mass measurements of stored and electron-cooled bare and few-electron ions. 373 different nuclides were identified by means of the spectra of their revolution frequencies. Masses for 18 nuclides (84Zr, 92Ru, 94Rh, 107,108,110Sb, 111,112,114I, 118Ba, 122,123La, 124Ce, 127Pr, 129Nd, 132Pm, 134Sm, 137Eu) have been determined for the first time. Masses for 111,112I and 113Xe have been obtained via known α-decay energies. The experiment and first results will be presented.  相似文献   

6.
Nuclear ground and isomeric state spins of several isotopes of the refractory elements (Y, Nb, Mo, Tc, Rh, Ta, Re, Os, Ir, Pt) measured by the atomic beam magnetic resonance method, are reported. The atomic ground-state g-factor for the Os atom has also been measured.  相似文献   

7.
The masses of 34 neutron-rich isotopes of fluorine through chlorine are reported. These measurements more fully delineate the mass surface in the region of deformed nuclei centered around 31Na and, in addition, provide the first mass values of several silicon through sulfur nuclei. We compare our data to recent shell model and mass model calculations  相似文献   

8.
Direct mass measurements of up to 6 isotopes for each of the elements chlorine through iron (over 35 masses) have been performed using the Time-of-Flight Isochronous (TOFI) spectrometer. We have used these measurements to: (1) investigate the local dependence of neutron and proton pairing energies on neutron excess, (2) find a new region of enhanced binding centered around53Sc, and (3) evaluate the predictive capabilities of several mass models.  相似文献   

9.
The cyclotron frequencies of singly charged carbon clusters Cn + (n ≥ 2) were measured with the Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN. The present limit of mass accuracy δm/m = 1.2 . 10-8 and the extent of the mass-dependent systematic shift (δm/m)sys = 1.7(0.6) . 10-10/u . (m - m ref) of the setup were investigated for the first time. In addition, absolute mass measurements by use of pure clusters of the most abundant carbon isotope 12C are now possible at ISOLTRAP. Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002 RID="a" ID="a"Present address: CERN, CH-1211 Geneva 23, Switzerland; e-mail: klaus.blaum@cern.ch  相似文献   

10.
Recent technical developments at ISOLTRAP include the design, installation and characterization of a new Channeltron-detector setup in order to increase the detection efficiency by about a factor of 3. Since a detection efficiency close to 100% is reached, true single-ion experiments can be performed for the first time and exotic nuclides further away from the valley of stability with lower production yields and/or shorter half-lives as compared to previous investigations are accessible. This publication comprises part of the thesis of C. Yazidjian.  相似文献   

11.
The direct mass measurements of the neutron-rich nuclei11Li,14Be,17B,19–20C,20–22N,23–24O, and25–27F have been performed using the Time-of-Flight Isochronous (TOFI) spectrometer. We observe a notable drop in the two-neutron separation energies for the oxygen and fluorine isotopes afterN=15. This behavior is interpreted using the shell model.  相似文献   

12.
The nuclear moments of the neutron-deficient187,188Tl isotopes were determined by measuring the hyperfine structure splittings of the λ=535 nm line in neutral thallium. An optical efficiency of 2×10−4 photons per radioactive ion was achieved using collinear fast beam laser spectroscopy with a large solid angle fiber optical array detector. Most of the moments can be interpreted fairly well in the single particle model.  相似文献   

13.
Bombarding targets of 106Cd,108Cd and110Cd with16O ions of 52.5–66.0 MeV neutron deficient barium, cesium and xenon isotopes were produced and have been studied using excitation functions and neutron-gamma, proton-gamma, alpha-gamma and gammagamma coincidence measurements. Partial level schemes for123Ba and121Ba were proposed. A number of gamma transitions was assigned to the different product nuclei. The measured particle emission probabilities from the compound nuclei are compared with different evaporation models. The models mostly underestimate neutron emission and often overestimate the emission of alpha particles.  相似文献   

14.
Bombarding targets of 106Cd,108Cd and110Cd with16O ions of 52.5–66.0 MeV neutron deficient barium, cesium and xenon isotopes were produced and have been studied using excitation functions and neutron-gamma, proton-gamma, alpha-gamma and gammagamma coincidence measurements. Partial level schemes for123Ba and121Ba were proposed. A number of gamma transitions was assigned to the different product nuclei. The measured particle emission probabilities from the compound nuclei are compared with different evaporation models. The models mostly underestimate neutron emission and often overestimate the emission of alpha particles.  相似文献   

15.
Cyclotron-produced thulium isotopes have been investigated using the atomic-beam magnetic resonance method. The spin measurements have given the following results: 159Tm (9 min) , 160Tm (9 min) I = 1, 161Tm (37 min) , 162Tm (21.5 min) I = 1, 164Tm (2 min) I = 1, 164m Tm (5 min) I = 6 and 168Tm (87 d) I = 3. An interpretation based on the Nilsson diagram for odd protons clearly indicates a systematic variation in the nuclear deformation.  相似文献   

16.
Even-A praseodymium activities have been produced and identified in the40Ca +92–96Mo reactions at 5.8 MeV/u:126Pr[T1/2=(3.0 ±0.4)s]128Pr[T1/2=(3.1 ±0.3)s],130Pr[T1/2 =(40.0 ±0.4)s]132Pr[T1/2=1.6 min]. Several new low-energy levels have been populated in even-even cerium nuclei.  相似文献   

17.
The hyperfine structure splitting and the isotope shift in the =266 nm transition of Pt isotopes within the mass range 183 A 198 have been determined by Resonance Ionization Mass Spectroscopy (RIMS) in combination with Pulsed-Laser Induced Desorption (PLID). The Pt isotopes were obtained at the on-line isotope separator ISOLDE-3/CERN as daugthers of the primarily produced Hg isotopes. Magnetic moments, quadrupole moments, and changes in the mean-square charge radii are deduced and compared with results of a particle-triaxial rotor model and mean field calculations. Good agreement with experimental data (including nuclear level schemes and transition probabilities) can only be obtained if triaxial shape is admitted. The calculations yield a smooth transition in the shape of odd-A Pt nuclei from a slightly deformed, nearly oblate195Pt via triaxial197-187Pt to a strongly deformed nearly prolate177Pt.Dedicated to P. Armbruster on the occasion of his 60th birthday  相似文献   

18.
19.
For a detailed study of the accuracy of the Penning trap mass spectrometer ISOLTRAP all expected sources of uncertainty were investigated with respect to their contributions to the uncertainty of the final result. In the course of these investigations, cross-reference measurements with singly charged carbon clusters 12C+ n were carried out. The carbon cluster ions were produced by use of laser-induced desorption, fragmentation, and ionization of C60 fullerenes and injected into and stored in the Penning trap system. The comparison of the cyclotron frequencies of different carbon clusters has provided detailed insight into the residual systematic uncertainty of ISOLTRAP and yielded a value of 8×10-9. This also represents the current limit of mass accuracy of the apparatus. Since the unified atomic mass unit is defined as 1/12 of the mass of the 12C atom, it will be possible to carry out absolute mass measurements with ISOLTRAP in the future. Received 7 June 2002 Published online 6 November 2002 RID="a" ID="a"e-mail: a.kellerbauer@cern.ch RID="b" ID="b"Current address: Centre de Physique des Particules de Marseille, 13288 Marseille Cedex 9, France.  相似文献   

20.
Direct mass measurements of neutron-deficient rare-earth isotopes in the vicinity of 146Gd were performed with the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. This paper reports on the measurement of more than 40 isotopes of the elements praseodymium, neodymium, promethium, samarium, europium, dysprosium and holmium, that have been measured with a typical accuracy of m 14 keV. An atomic mass evaluation has been performed taking into account other experimental mass values via a least-squares adjustment. The results of the adjustment are discussed. Received: 18 April 2000 / Accepted: 12 July 2000  相似文献   

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