共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
V. Scuderi M. Zadro A. Di Pietro P. Figuera M. Lattuada F. Pansini M. Papa D. Vinciguerra O. Yu. Goryunov A. Khouaja V. Lyapin C. Nociforo V. V. Ostashko 《The European physical journal. Special topics》2007,150(1):53-54
The resonance scattering method in inverse kinematics on infinite target has been applied to two systems, 18O + α and 9Be + α, in order to test and to optimize an experimental apparatus in view of a set of resonance scattering experiments to
be performed with 8Li and 9Li radioactive ion beams delivered by the facility EXCYT. The scattering excitation functions, deduced for the two systems,
were compared with previous results reported in literature. Results show that reliable stopping power data are essential for
the application of this technique. 相似文献
3.
A new version of integrated target-ion source unit (ionising target) has been developed for the on-line production of radioactive
single-charged ions. The target is able to withstand temperatures up to 2500 °C and acts also as an ion source of the surface and laser ionisation. Off-line and on-line experiments with the ionising target,
housing tantalum foils as a target material, have been carried out at the IRIS (Investigation of Radioactive Isotopes on Synchrocyclotron)
facility. The off-line surface ionisation efficiency measured for stable atoms of Li, Rb and Cs was correspondingly 6% , 40%
and 55% at the target temperature of 2000 °C and 3-10% for atoms of rare-earth elements Sm, Eu, Tm and Yb at a temperature of 2200 °C. The off-line measured values of the ionisation efficiency for stable Gd and Eu atoms by the laser beam ionisation inside
the target were 1% and 7%, respectively. The radioactive beam intensities of neutron-deficient rare-earth nuclides from Eu
to Lu produced by the integrated target-ion source unit have been measured at a temperature of 2500 °C. The results of the integrated target-ion source unit use for on-line laser resonance ionisation spectroscopy study of neutron-deficient
Gd isotopes have been also presented. 相似文献
4.
U. Kentsch T. Werner G. Zschornack F. Grossmann V.P. Ovsyannikov F. Ullmann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,17(3):297-305
Irq+ ( 41≤q≤64) ions with open-shell configurations have been produced in the electron beam of the room-temperature Dresden Electron
Beam Ion Trap (Dresden EBIT) at electron excitation energies from 2 keV to 13 keV. X-ray emission from direct excitation processes
and radiative capture in krypton-like to aluminium-like iridium ions is measured with an energy dispersive Si(Li) detector.
The detected X-ray lines are analyzed and compared with results from multiconfigurational Dirac-Fock (MCDF) atomic structure
calculations. This allows to determine dominant produced ion charge states at different electron energies. The analysis shows
that at the realized working gas pressure of 5×10-9mbar for higher charged ions the maximum ion charge state is not preferently determined by the chosen electron beam energy
needed for ionization of certain atomic substates, but by the balance between ionization and charge state reducing processes
as charge exchange and radiative recombination. This behaviour is also discussed on the basis of model calculations for the
resulting ion charge state distribution.
Received 12 July 2001 and Received in final form 10 September 2001 相似文献
5.
G. Bisoffi 《The European physical journal. Special topics》2007,150(1):219-224
The accelerator group at INFN-LNL has been mostly engaged, recently, in completing and commissioning the
higher current injector of the linac booster ALPI (named PIAVE) and in constructing and assembling the front-end part of a
high current driver linac for the RNB facility SPES. PIAVE, designed to accelerate ions with A/Q = < 8.5 up to 1.2 MeV/u,
is now completed. The injector has been commissioned with O, Ar, Ne and Xe beams. Neon and argon beams have been delivered
to
experiments for a total of about 400 hours. A consolidation program of PIAVE and ALPI is planned, so as to deliver a larger
variety
of beams with a current range
pnA and with an energy exceeding the Coulomb barrier in relevant nuclear reaction cases.
The RNB facility SPES, allowing a frontier program in RNB physics, is being designed and prototyped: beams of neutron rich
medium-to-heavy mass nuclei will be produced inducing 238U fission with a 40 MeV 200μA proton beam impinging onto
a multi-slice direct target. A further development of ALPI will make it best suitable for the re-acceleration of radioactive
nuclear species, after charge breeding and isotope selection. 相似文献
6.
A. Cunsolo F. Cappuzzello M. Cavallaro A. Foti A. Khouaja S. E.A. Orrigo J. S. Winfield L. Gasparini G. Longo T. Borello-Lewin M. R.D. Rodrigues M. D.L. Barbosa C. Nociforo H. Petrascu 《The European physical journal. Special topics》2007,150(1):343-346
The MAGNEX large-acceptance spectrometer has been
commissioned with beams from the Tandem accelerator
at INFN-LNS Catania. The optics were tested
with elastically-scattered 7Li, 16O and 48Ti
beams with various apertures mounted after the target.
The momentum dispersion was verified to be in agreement with
the optics calculations.
A demonstration of the particle identification capabilities
of the PSD start detector and the focal plane detector
was given by a measurement of the 27Al(7Li,6Li)28Al
transfer reaction at
a mean angle of 25°. The measured charge
state distribution of 48Ti ions is
in agreement with predictions for a gold stripping foil.
Preliminary
results of the software reconstruction of incident angle and
excitation energy, obtained through matrices based
on a 3D-interpolation of the measured field maps, are encouraging. 相似文献
7.
J. Gerl 《The European physical journal. Special topics》2007,150(1):353-356
Nuclear spectroscopy using radioactive isotope beams
requires dedicated set-ups. State-of-the-art Ge arrays recently started to
provide valuable γ spectroscopic data. At the SIS/FRS facility at
GSI exotic beams at relativistic energies were employed for Coulomb
excitation and secondary fragmentation experiments with the fast beam RISING
set-up. Shell evolution far off stability, pn-pairing, symmetries and
nuclear shapes were studied in nuclei ranging from 36Ca to 136Nd.
The observation of a I = 27 ħ state demonstrated that high spin states can
be reached in massive fragmentation reactions. This and the large
sensitivity of relativistic in-beam experiments opens a rich ground for
advanced nuclear structure studies. Combining RISING with AGATA γ-tracking detectors and improved particle detection is planned
for future
experimental investigations. 相似文献
8.
Y. X. Watanabe S. Arai Y. Arakaki Y. Fuchi Y. Hirayama N. Imai H. Ishiyama S. C. Jeong H. Kawakami H. Miyatake K. Niki T. Nomura M. Okada M. Oyaizu M. H. Tanaka M. Tomizawa N. Yoshikawa S. Abe S. Hanashima T. Hashimoto S. Ichikawa H. Ikezoe T. Ishii N. Ishizaki H. Kabumoto I. Katayama M. Koizumi M. Matsuda S. Mitsuoka T. Nakanoya K. Nishio I. Ohuchi A. Osa T. K. Sato S. Takeuchi H. Tayama Y. Tsukihashi 《The European physical journal. Special topics》2007,150(1):259-262
An ISOL-based radioactive nuclear beam (RNB) facility,
Tokai Radioactive Ion Accelerator Complex (TRIAC),
has been jointly developed
by High Energy Accelerator Research Organization (KEK)
and Japan Atomic Energy Agency (JAEA).
The facility started to supply RNBs for experiments in 2005
and RNBs including fission fragments with energies up to 1.1MeV/A
are available in the present.
Several experimental studies were performed successfully
using 8Li beams
with various energies. 相似文献
9.
J. Benlliure T. Kurtukian-Nieto L. Audouin B. Blank F. Becker E. Casarejos D. Cortina M. Fernández-Ordóñez J. Giovinazzo D. Henzlova B. Jurado J. Pereira F. Rejmund K.-H. Schmidt O. Yordanov 《The European physical journal. Special topics》2007,150(1):309-310
The production of heavy neutron-rich nuclei is investigated using cold-fragmentation reactions.
More than 25 new heavy neutron-rich nuclei were produced in the fragmentation of 208Pb projectiles at 1 A GeV impinging a
beryllium target. The precise measurement of their production cross sections enables to benchmark the predictive power of
different
model calculations and make reliable predictions of the production rates expected in future radioactive beam facilities. 相似文献
10.
C. Gund H. Bauer J. Cub A. Dietrich T. Härtlein H. Lenske D. Pansegrau A. Richter H. Scheit G. Schrieder D. Schwalm 《The European Physical Journal A - Hadrons and Nuclei》2001,10(1):85-95
As a tool for studying the structure of nuclei far off stability the technique of γ-ray spectroscopy after low-energy single-nucleon
transfer reactions with radioactive nuclear beams in inverse kinematics was investigated. Modules of the MINIBALL germanium
array and a thin position-sensitive parallel plate avalanche counter (PPAC) to be employed in future experiments at REX-ISOLDE
were used in a test experiment performed with a stable 36S beam on deuteron and 9Be targets. It is demonstrated that the Doppler broadening of γ lines detected by the MINIBALL modules is considerably reduced
by exploiting their segmentation, and that for beam intensities up to 106 particles/s the PPAC positioned around zero degrees with respect to the beam axis allows not only to significantly reduce
the γ background by requiring coincidences with the transfer products but also to control the beam and its intensity by single
particle counting. The predicted large neutron pickup cross-sections of neutron-rich light nuclei on 2H and 9Be targets at REX-ISOLDE energies of 2.2 MeV .
A are confirmed.
Received: 9 October 2000 / Accepted: 28 January 2001 相似文献
11.
《Nuclear Physics A》1995,588(1):c273-c276
A radioactive ion beam facility, GIRAFFE, has been built at the CIAE HI-13 Tandem accelerator. The facility makes use of the inverse kinematics. A D-Q-Q type magnetic separation and focusing system was used in the beam line. This simple device is expected to yield some radioactive ion beams(A<20) near the β-stability line with the acceptable intensities(105–106 pps). The ion beams of 7Be, 11C and 17F were delivered, and the 7Be beam was applied for two experiments. 相似文献
12.
T. Glasmacher B.V. Pritychenko P.D. Cottle R.W. Ibbotson K.W. Kemper H. Scheit 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):59-62
Projectile fragmentation provides radioactive beams at intermediate velocities (v/c = 0.3-0.5) by physical means of fragment separation. With the development of position-sensitive photon detectors it has become
possible to measure the energies and directions of photons emitted in-flight from such fast-moving exotic beams. This allows
the reconstruction of the photons' energies emitted from an exotic projectile with high accuracy. It can be advantageous to
employ photon detection in experiments with exotic beams since photons can traverse matter easily and their attenuation can
be calculated. Experiments with standard luminosities can be carried out at intermediate beam energies with thick secondary
targets (order of g/cm2) and very low incident beam rates (order of particle/s or less). Experimental success in this field is strongly correlated
with the development of photon detectors such as position-sensitive scintillation detectors or segmented germanium detectors.
In-beam gamma-ray spectroscopy of fast exotic beams has been successfully used at all projectile fragmentation facilities
in intermediate-energy heavy-ion inelastic scattering experiments, knockout reactions and fragmentation reactions. Here, we
focus on experimental results for neutron-rich exotic nuclei in the π(sd )-shell. Measurements and detector developments carried out at the NSCL at Michigan State University during the last four
years are discussed.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
13.
C. Hugenschmidt K. Schreckenbach D. Habs P. G. Thirolf 《Applied physics. B, Lasers and optics》2012,106(1):241-249
Presently, large efforts are conducted toward the development of highly brilliant γ beams via Compton back scattering of photons from a high-brilliance electron beam, either on the basis of a normal-conducting
electron linac or a (super-conducting) Energy Recovery Linac (ERL). Particularly, ERLs provide an extremely brilliant electron
beam, thus enabling the generation of highest-quality γ beams. A 2.5 MeV γ beam with an envisaged intensity of 1015 photons s−1, as ultimately envisaged for an ERL-based γ-beam facility, narrow band width (10−3), and extremely low emittance (10−4 mm2 mrad2) offers the possibility to produce a high-intensity bright polarized positron beam. Pair production in a face-on irradiated
W converter foil (200 μm thick, 10 mm long) would lead to the emission of 2×1013 (fast) positrons per second, which is four orders of magnitude higher compared to strong radioactive 22Na sources conventionally used in the laboratory. Using a stack of converter foils and subsequent positron moderation, a high-intensity
low-energy beam of moderated positrons can be produced. Two different source setups are presented: a high-brightness positron
beam with a diameter as low as 0.2 mm, and a high-intensity beam of 3×1011 moderated positrons per second. Hence, profiting from an improved moderation efficiency, the envisaged positron intensity
would exceed that of present high-intensity positron sources by a factor of 100. 相似文献
14.
R.I. Badran D.J. Parker I.M. Naqib 《The European Physical Journal A - Hadrons and Nuclei》2001,12(3):317-325
Excitation functions for the production of eight radioactive products of the reactions of 7Li on 56Fe have been measured up to E(7
Li) = 89 MeV. Recoil range distributions for these products, together with inclusive proton, deuteron, triton and alpha spectra,
have been measured at energies of 50 and 68 MeV. The α, t and d spectra show characteristic “break-up” components at forward
angles, while the recoil distributions show evidence of complete fusion and incomplete-fusion process 56Fe( 7Li,α) 59Co * . A parallel study on 55Mn shows some evidences of the ( 7Li,t) incomplete-fusion process, but the cross-section for this process is significantly less than for the triton fusion process.
The recoil distributions can be reproduced on the assumption that essentially all the observed break-up fragments are in fact
associated with incomplete fusion, but uncertainties in normalisation leave open the possibility of a significant contribution
of pure break-up. A diffraction model of the ( 7Li,α) transfer process reproduces the observed break-up α spectra with some success.
Received: 29 March 2001 / Accepted: 12 November 2001 相似文献
15.
G. Stancari S. N. Atutov R. Calabrese L. Corradi A. Dainelli C. de Mauro A. Khanbekyan E. Mariotti P. Minguzzi L. Moi S. Sanguinetti L. Tomassetti S. Veronesi 《The European physical journal. Special topics》2007,150(1):389-392
Francium is one of the best candidates for atomic parity
nonconservation (APNC) and for the search of permanent electric
dipole moments (EDMs). APNC measurements test the weak force
between electrons and nucleons at very low momentum transfers. They
also represent a unique way to detect weak nucleon-nucleon
interactions. EDMs are instead related to the time-reversal
symmetry. Preliminary to these fundamental measurements are
precision studies in atomic spectroscopy and the development of
magneto-optical traps (MOT), which partially compensate for the lack
of stable Fr isotopes. At LNL Legnaro, francium is produced by
fusion of 100-MeV 18O with 197Au in a thick target,
followed by evaporation of neutrons from the compound nucleus.
Francium diffuses inside the hot target (1200 K) and is surface
ionized for injection at 3 keV in an electrostatic beamline.
Typically, we produce 1×106 (210Fr ions)/s for a
primary flux of 1.5×1012 particles/s. We have studied
Fr yields as a function of primary beam energy, intensity, and
target temperature. Information on the efficiency of bulk
diffusion, surface desorption and ionization is deduced. The beam
then enters a Dryfilm-coated cell, where it is neutralized on a
heated yttrium plate. The escape time of neutral Fr (diffusion +
desorption) is approximately 20 s at 950 K, as measured with a
dedicated setup. In the MOT, we use 6 orthogonal Ti:sapphire laser
beams for the main pumping transition and 6 beams from a stabilized
diode repumper. Fluorescence from trapped atoms is observed with a
cooled CCD camera, in order to reach noise levels from stray
light equivalent to approximately 50 atoms. Systematic tests are
being done to improve the trapping efficiency. We plan to further
develop Fr traps at LNL; in parallel, we will study APNC and EDM
techniques and systematics with stable alkalis at Pisa, Siena, and
Ferrara. 相似文献
16.
M. Marchetto Z. T. Ang K. Jayamanna R. E. Laxdal A. Mitra V. Zvyagintsev 《The European physical journal. Special topics》2007,150(1):241-242
ISAC at TRIUMF is a world-class facility for the production and post-acceleration of radioactive ion beams (RIB).
Commissioned in 2002 the ISAC I linear accelerator serves three different beam lines delivering
both stable and radioactive species.
Two of them are permanent experiments (DRAGON and TUDA); the third one is a general purpose station (GPS).
The maximum energy we can reach in ISAC I is 1.8 MeV/u.
ISAC II is a phased upgrade of the ISAC facility. The beam coming from ISAC I is injected at 1.5 MeV/u into
a new superconducting LINAC. In `Phase I' the LINAC adds 20 MV to the beam energy
and 20 MV more will be added in `Phase II'.
The paper will give an overview of both the ISAC I and ISAC II accelerators.
Operational experience with accelerating RIBs in ISAC I is summarized.
First ISAC II commissioning results are presented. 相似文献
17.
Total charge exchange cross sections were measured for He++ in He and Ar gas in the energy range from 50 to 540 eV using a single beam apparatus. For He++ in He the measured cross section is in agreement with calculations for symmetric resonant charge exchange. For He++ in Ar the cross section for charge exchange decreases with decreasing energy below 300 eV. The measured cross section suggests the formation of Ar+ ions to be more important at lower energies and the production of Ar++ to be dominant at higher energies. 相似文献
18.
P. Mason N. Marginean G. Montagnoli S. Beghini F. Scarlassara E. Farnea C. A. Ur A. Meroni A. M. Stefanini L. Corradi E. Fioretto I. V. Pokrovskiy B. Guiot A. Gadea J. J. Valiente-Dobón F. Della Vedova R. Orlandi E. Sahin D. R. Napoli L. Berti N. Toniolo S. Szilner M. Trotta M. Romoli M. La Commara D. Pierroutsakou M. Sandoli G. Pollarolo G. Benzoni 《The European physical journal. Special topics》2007,150(1):359-361
PRISMA is a magnetic
spectrometer installed at Laboratori Nazionali di Legnaro (Italy)
and designed for A=100–200, E=5–10 MeV-per-nucleon beams, and for
possible use with the proposed radioactive beam facility SPES. The
foremost features of the instrument are presented, along with the
outline of two data analyses exemplifying the effectiveness of
PRISMA-CLARA in studies of reaction
dynamics. 相似文献
19.
C. Signorini M. Mazzocco G.F. Prete F. Soramel L. Stroe A. Andrighetto I.J. Thompson A. Vitturi A. Brondi M. Cinausero D. Fabris E. Fioretto N. Gelli J.Y. Guo G. La Rana Z.H. Liu F. Lucarelli R. Moro G. Nebbia M. Trotta E. Vardaci G. Viesti 《The European Physical Journal A - Hadrons and Nuclei》2001,10(3):249-253
Large cross-section reaction channels were measured in the systems 6Li( 7Li) + 208Pb with high statistical accuracy at 5(3) energies around the Coulomb barrier from 29 to 39 MeV. These channels were assigned
(mainly) to the breakup of 6Li, very loosely bound, into α + d and to the breakup of 5Li, produced by n-transfer to the target, into α + p and to similar processes with 7Li beam. The cross-sections with 6Li, S
α = 1.475 MeV, are systematically larger than the 7Li ones. This reflects, most likely, the higher binding energy of 7Li, S
α = 2.468 MeV. Theoretical predictions for the 6Li + 208Pb system which include for 6Li breakup to continuum states within a continuum discretized coupled-channels approach (CDCC) and resonant breakup plus n-transfer
with DWBA reproduce the angular distribution shapes but still underestimate the cross-sections by a factor ∼ 3.
Received: 15 January 2001 / Accepted: 3 March 2001 相似文献
20.
M. Wada Y. Ishida T. Nakamura Y. Kanai T. M. Kojima A. Takamine Y. Yamazaki K. Okada A. Yoshida T. Kubo I. Katayama S. Ohtani V. Varentsov H. Wollnik V. Lioubimov H. A. Schuessler 《Hyperfine Interactions》2006,173(1-3):153-163
A next-generation slow radioactive nuclear ion beam facility (SLOWRI) which provides slow, high-purity and small emittance ion beams of all elements is being build as one of the principal facilities at the RIKEN RI-beam factory (RIBF). High energy radioactive ion beams from the projectile fragment separator BigRIPS are thermalized in a large gas catcher cell. The thermalized ions in the gas cell are guided and extracted to a vacuum environment by a combination of dc electric fields and inhomogeneous rf fields (rf carpet ion guide). From there the slow ion beam is delivered via a mass separator and a switchyard to various devices: such as an ion trap, a collinear fast beam apparatus, and a multi-reflection time of flight mass spectrometer. In the R&D works at the present RIKEN facility, an overall efficiency of 5% for a 100A MeV 8Li ion beam from the present projectile fragment separator RIPS was achieved and the dependence of the efficiency on the ion beam intensity was investigated. Recently our first spectroscopy experiment at the prototype SLOWI was performed on Be isotopes. Energetic ions of 10Be and 7Be from the RIPS were trapped and laser cooled in a linear rf trap and the specific mass shifts of these isotopes were measured for the first time. 相似文献