Search results for "EXCITATION"
showing 10 items of 1290 documents
Laser ion source tests at the HRIBF on stable Sn, Ge and Ni isotopes
2006
Abstract As one step in the ion source development for the Rare Isotope Accelerator, a hot-cavity laser ion source using an all-solid-state titanium–sapphire laser system has been tested at the Holifield Radioactive Ion Beam Facility. Resonance ionization of stable isotopes of Sn, Ge and Ni has been studied in a Ta hot cavity. Efficient three step resonant ionization schemes applying frequency tripling for the first excitation step and using auto-ionizing or atomic Rydberg states in the ionizing step have been identified for all three elements, resulting in laser ion beams of typically around 100 nA. By saturating most of the optical excitation steps involved, ionization efficiencies of 22%…
Laser resonance ionization for efficient and selective ionization of rare species
2003
Abstract Due to the steady development and refinement of powerful pulsed as well as continuous-wave lasers, resonance ionization has developed into an extremely versatile tool for numerous applications. Apart from suppressing isobaric interferences and contributing to isotopic selectivity already in the ionization process, resonant optical excitation and ionization with laser light ensures high overall efficiency and good temporal and spatial controls of the ions delivered to mass spectrometric applications. In the field of rare isotope research laser resonance ionization has nowadays become one of the key techniques, including similarly the determination of long-lived or stable ultra-trace…
The REX-ISOLDE project
1998
Abstract REX-ISOLDE [1] is an experiment at ISOLDE/CERN with a twofold aim: (i) to demonstrate a novel efficient scheme for the acceleration of radioactive ions from the online mass separator ISOLDE to energies around the Coulomb barrier. (ii) to perform first nuclear physics experiments by studying the structure of the neutron-rich (N = 20, N = 28) nuclei by Coulomb excitation and neutron transfer reactions. An overview on the different components of the radioactive beam accelerator is given with special emphasis on the separation possibilities and ion number capabilities of the system.
ESR and PL centers induced by gamma rays in silica
1996
We have studied the point defects created by γ irradiation in various types of commercial silica glasses, including both natural and synthetic samples, with different OH content, in the low dose regime (0.05–100 Mrad). We found that the growth rate of E′ centers depends strongly on the silica type, ranging from 2 × 1015 cm−3 Mrad−1 to 6 × 1017 cm−3 Mrad−1. Samples of natural silica are rather susceptible to γ ray exposure, as E′ concentration saturates (typically 5 × 1017 cm−3) for doses as low as a few Mrads. For both synthetic and natural samples, the radiation hardness is higher in wet than in dry silica. Moreover, we found a strict correlation between the concentration of E′ centers and…
Low temperature X-ray luminescence of KNbO3 crystals
2000
We have studied X-ray luminescence of KNbO3 single crystal. The 575 nm luminescence band has been studied in the temperature range of 15‐45 K. The quenching parameters were found to be Qa 12 3 meV and ma 4 10 11 s ˇ1 .N o luminescence has been observed under heavy ion excitation ( 86 Kr ions, 8.63 MeV/amu) even at 15 K. ” 2000 Elsevier
Experimental program of the Super-FRS Collaboration at FAIR and developments of related instrumentation
2016
The physics program at the super-conducting fragment separator (Super-FRS) at FAIR, being operated in a multiple-stage, high-resolution spectrometer mode, is discussed. The Super-FRS will produce, separate and transport radioactive beams at high energies up to 1.5 AGeV, and it can be also used as a stand-alone experimental device together with ancillary detectors. Various combinations of the magnetic sections of the Super-FRS can be operated in dispersive, achromatic or dispersion-matched spectrometer ion-optical modes, which allow measurements of momentum distributions of secondary-reaction products with high resolution and precision. A number of unique experiments in atomic, nuclear and h…
Simulating core excitation in breakup reactions of halo nuclei using an effective three-body force
2022
We extend our previous calculation of the breakup of 11Be using Halo Effective Field Theory and the Dynamical Eikonal Approximation to include an effective 10Be-n-target force. The force is constructed to account for the virtual excitation of 10Be to its low-lying 2+ excited state. In the case of breakup on a 12C target this improves the description of the neutron-energy and angular spectra, especially in the vicinity of the 11Be 5/2+ state. By fine-tuning the range parameters of the three-body force, a reasonable description of data in the region of the 3/2+ 11Be state can also be obtained. This sensitivity to the three-body force's range results from the structure of the overlap integral …
First observation of high-K isomeric states in $$^{249}$$Md and $$^{251}$$Md
2021
Decay spectroscopy of the odd-proton nuclei $^{249}$Md and $^{251}$Md has been performed. High-K isomeric states were identified for the first time in these two nuclei through the measurement of their electromagnetic decay. An isomeric state with a half-life of 2.8(5) ms and an excitation energy $\ge 910$ keV was found in $^{249}$Md. In $^{251}$Md, an isomeric state with a half-life of 1.4(3) s and an excitation energy $\ge 844$ keV was found. Similarly to the neighbouring $^{255}$Lr, these two isomeric states are interpreted as 3 quasi-particle high-K states and compared to new theoretical calculations. Excited nuclear configurations were calculated within two scenarios: via blocking nucle…
First evidence for a charm radial excitation, D
1998
Using D*+ mesons exclusively reconstructed in the DELPHI detector at LEP, an excess of 66 +/- 14(stat.) events is observed in the D(*+)pi(+)pi(-) final state with a mass of 2637 +/- 2(stat.) +/- 6(syst.) MeV/c(2) and a full width smaller than 15 MeV/c(2) (95% C.L.). This signal is compatible with the expected decay of a radially excited D*' (J(P) = 1(-))meson. (C) 1998 Published by Elsevier Science B.V. All rights reserved.
A search for $\eta'_c$ production in photon-photon fusion at LEP
1998
A search for the production of the $\eta'_c$ meson, the first radial excitation of the ground state of charmonium $\eta_c$(2980), in the photon-photon fusion reaction at LEP has been performed using the data collected by the DELPHI detector during 1992-1996. No evidence of $\eta'_c$ production is found in the mass region 3520--3800 MeV/c^2. An upper limit for the ratio of the two-photon widths of the $\eta'_c$ and $\eta_c$ is obtained.