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1.
J.A. Nolen 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):255-261
There are several nuclear physics laboratories in North America that have on-going research using energetic and stopped radioactive
beams. These include the large ISOL-type programs ISAC at TRIUMF and HRIBF at Oak Ridge and the in-flight fragmentation program
at the NSCL of Michigan State University. There are also smaller, more specialized, programs using a variety of techniques
at the 88-inch cyclotron of Berkeley, ATLAS at Argonne, the Cyclotron Institute of Texas A&M University, the Nuclear Structure
Laboratory at Notre Dame University, and the Nuclear Structure Laboratory at SUNY/Stony Brook. There are also three projects
on the horizon in North America for new capabilities in both the near term and more distant future. The intensities of the
in-flight fragment beams at the NSCL will be increased dramatically very soon as the Coupled Cyclotron Project will be completed
and commissioned for research by mid-2001. A new project, ISAC-II, has been approved in Canada. For the longer term, the United
States is considering construction of a major new facility, the Rare Isotope Accelerator (RIA), which would have a very high-intensity
heavy-ion driver linac. The RIA facility is proposed to utilize both ISOL and in-flight production mechanisms.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
2.
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
3.
D.J. Morrissey 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):105-108
The physics opportunities made possible by beams of rare isotopes are among the richest available in nuclear science. The
rare-isotope accelerator (RIA) now under development is an innovative accelerator that will define the state of the art for
all such facilities. A novel aspect of the RIA project is the conversion of the most intense high-energy heavy-ion beams into
both fast and reaccelerated exotic beams. Along with target fragmentation in next-generation high-power ISOL targets, RIA
will use projectile fragmentation in a high-energy separator/gas-filled ion collector system to provide an extensive range
of thermalized ions for reacceleration. In addition, a second high-energy separator will provide the same or larger range
of ions for high-energy experiments. A brief overview of the RIA accelerator concept, the layout of the facility, and production
techniques will be given along with information on the present R&D efforts in gaseous-ion collection.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: morrissey@nscl.msu.edu 相似文献
4.
P. Campbell A. Nieminen J. Billowes P. Dendooven K.T. Flanagan D.H. Forest Yu.P. Gangrsky J.A.R. Griffith J. Huikari A. Jokinen I.D. Moore R. Moore H.L. Thayer G. Tungate S.G. Zemlyanoi J. Äystö 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):45-48
A new RFQ ion-beam cooler and buncher, installed after the mass-separating magnet of the ion guide isotope separator, IGISOL,
JYFL, has dramatically increased the scope of on-line laser spectroscopy at this facility. The device, operated in a bunching
mode, has permitted new measurements on short-lived radionuclei in the Ti, Zr and Hf chains at a sensitivity two orders of
magnitude greater than that previously achieved. The device has also opened new prospects for laser-based nuclear spectroscopy
at the facility, particularly collinear resonance ionisation spectroscopy.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: pc@mags.ph.man.ac.uk 相似文献
5.
We present experimental evidence that the free-electron laser at the TESLA Test Facility has reached the maximum power gain
of 107 in the vacuum ultraviolet (VUV) region at wavelengths between 80 and 120 nm. At saturation the FEL emits short pulses with
GW peak power and a high degree of transverse coherence. The radiation pulse length can be adjusted between 30 fs and 100
fs. Radiation spectra and fluctuation properties agree with the theory of high gain, single-pass free-electron lasers starting
from shot noise.
Received 26 April 2002 Published online 28 June 2002 相似文献
6.
F. Ibrahim J. Obert O. Bajeat J.M. Buhour D. Carminati F. Clapier C. Donzaud M. Ducourtieux J.M. Dufour S. Essabaa S. Galès D. Guillemaud-Mueller F. Hosni O. Hubert A. Joinet U. Köster C. Lau H. Lefort G. Le Scornet J. Lettry A.C. Mueller M. Mirea N. Pauwels O. Perru J.C. Potier J. Proust F. Pougheon H. Ravn L. Rinolfi G. Rossat H. Safa M.G. Saint Laurent M. Santana-Leitner O. Sorlin D. Verney 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):357-360
A PARRNe 1 experiment (Production d'Atomes Radioactifs Riches en Neutrons) aimed at the production of neutron-rich radioactive
noble gases produced by photofission has been performed at CERN. The LEP Pre-Injector (LPI) has been used to deliver a 50
MeV electron beam. The results obtained show clearly that the use of an electron beam to produce neutron-rich fission fragments
for futur RNB facilities is an option that should not be neglected.
Received: 20 July 2001 / Accepted: 5 June 2002 / Published online: 19 November 2002
RID="a"
ID="a"e-mail: ibrahim@ipno.in2p3.fr
Communicated by D. Guerreau 相似文献
7.
8.
M. Gaelens J. Andrzejewski J. Camps P. Decrock M. Huyse K. Kruglov W.F. Mueller A. Piechaczek N. Severijns J. Szerypo G. Vancraeynest P. Van Duppen J. Wauters 《The European Physical Journal A - Hadrons and Nuclei》2001,11(4):413-420
A high-precision measurement of the 14O half-life has been performed using a mass-separated radioactive beam in combination with a germanium detector set-up. This
is the first 14O half-life measurement with a contamination-free source. The final result of 70.560 ± 0.049 seconds is in agreement with
the generally adopted mean value.
Received: 5 April 2001 / Accepted: 6 August 2001 相似文献
9.
Target-ion source unit ionization efficiency measurement by a method of stable ion beam implantation
V. N. Panteleev A. E. Barzakh D. V. Fedorov P. L. Molkanov F. V. Moroz S. Yu. Orlov Yu. M. Volkov 《The European physical journal. Special topics》2007,150(1):301-302
At the IRIS facility a rather precise method of the
target-ion source unit ionization efficiency measurement has been
developed. The method exploits an off-line
mass-separator for the implantation of the ion beams of selected stable isotopes into a tantalum foil placed inside a Faraday
cup
in the focal plane of the mass-separator. After the
implantation of the required amount of the investigated species, tantalum foil has been inserted into
the volume of the target-ion source unit prepared for the on-line utilization at the IRIS
on-line separator. The first tests have ensured the ionization efficiency values
(90±10)% for Rb and (85±10)% for Cs in the empty combined
target-ion source unit, which was
used as a reference one. For the target-ion source unit with UC target material inside the measured value of the ionization
efficiency of Rb was (52±20)%. 相似文献
10.
K. Kruglov A. Andreyev B. Bruyneel S. Dean S. Franchoo M. Górska K. Helariutta M. Huyse Yu. Kudryavtsev W.F. Mueller N.V.S.V. Prasad R. Raabe K.-H. Schmidt P. Van Duppen J. Van Roosbroeck K. Van de Vel L. Weissman 《The European Physical Journal A - Hadrons and Nuclei》2002,14(3):365-370
Heavy 65-70Co, 68-74Ni, 70-76Cu and 74-81Ga isotopes were produced at the LISOL facility by means of 30 MeV proton-induced fission of 238U. Production rates were deduced and compared to two types of cross-section calculations: the empirical model (V. Rubchenya,
private communication) and the PROFI code. Comparison with experimental data favors the latter model. Yields using different
beam-target combinations and different energies are calculated and discussed.
Received: 11 February 2002 / Accepted: 26 April 2002 相似文献
11.
P. Bricault 《The European physical journal. Special topics》2007,150(1):227-232
The ISAC facility at TRIUMF utilizes up to 100 μA from the 500 MeV H- cyclotron to produce the RIB using the Isotopic Separation On Line (ISOL) method. The ISAC-I facility comprised the RNB production
target stations, the mass separator and the beam delivery to low energy area and to a room temperature linear accelerator
composed of a 4-rod RFQ and an inter-digital H type structure Drift Tube LINAC. ISAC-I linear accelerator can provide beam
from A = 3 to 30 amu with an energy range from 0.15 to 1.5 A MeV.
Since the beginning of operations target development program has been to increase proton beam currents on targets. Now we
routinely operate our target at 50 to 85 μA and recently we have operated our target at 100 μA. Other developments are in
place to add other ion sources, laser, FEBIAD and ECRIS to the actual surface ion source. The last two five year plans were
mainly devoted to the construction of a heavy ion superconducting LINAC (ISAC-II), that will upgrade the mass and the energy
range from 30 to 150 and 1.5 to 6.5 A MeV, respectively.
We are now commissioning the medium β section and first experiment is scheduled for the fall 2006. 相似文献
12.
R. E. Tribble F. Abegglen G. Chubarian H. L. Clark G. Derrig G. Kim D. May G. A. Souliotis G. Tabacaru 《The European physical journal. Special topics》2007,150(1):255-258
The Cyclotron Institute at Texas A&M University is carrying out an upgrade project
which will lead to accelerated radioactive ion beams at intermediate energies. The project
involves recommissioning a K150 cyclotron for acceleration of stable beams which will be used
to produce radioactive ions. Both light-ion and heavy-ion guides will be used
to stop and transport the radioactive ions to a charge breeding electron cyclotron resonance ion
source. Following charge breeding, highly-charged ions will be injected into the K500 cyclotron,
accelerated and then transported to existing equipment to carry out experiments. 相似文献
13.
V. Rizzi A. L. Lanchais G. Lehrsonneau 《The European physical journal. Special topics》2007,150(1):307-308
Experiments done using on-line mass separation of neutron-rich nuclei produced by 1 GeV proton beam
on natural U by spallation reactions are performed to study the characteristics of different UCx
targets.
Special attention is devoted to reliably extract isotopic yields in case of complex decay schemes
and to the valuation of release efficiency of some isotopic chains. New gamma-branching measuremet for
92Rb are obtained. In addition, a formalism is developed to disantangle the contribution of β-decay
in the target from direct production by fission and to provide more consistent data for the
interpretation of release curves. Some results are shown for the Cs and Rb isotopic chains. 相似文献
14.
D. J. Morrissey 《The European physical journal. Special topics》2007,150(1):365-366
The NSCL gas cell and quadrupole ion-guide system has been
used to study the thermalization of fast nuclear reaction products
in a buffer gas. The fraction of radioactive ions that can be
extracted from the gas cell is dramatically suppressed by space
charge created by the stopping ions. The results of a review of the
ion yields from the NSCL and from other gas cells from the
literature with different sizes and different incident particle
energies shows an overall consistency with a dramatic decline in
extraction efficiency at high ionization rates. 相似文献
15.
V. N. Panteleev O. Alyakrinskiy A. Andrighetto A. E. Barzakh M. Dubois C. Eleon S. Essabaa O. Bajeat D. V. Fedorov G. Gaubert A. M. Ionan V. S. Ivanov P. Jardin A. Lanchais C. Lau R. Leroy G. Lhersonneau C. Mhamed K. A. Mezilev P. L. Molkanov F. V. Moroz S. Yu. Orlov V. Rizzi M. G. Saint Laurent L. Stroe L. B. Tecchio A. C.C. Villari Yu. M. Volkov 《The European physical journal. Special topics》2007,150(1):297-300
The capacity of uranium carbide target materials of
different structure and density for production of neutron-rich and
heavy neutron-deficient nuclides have been investigated. The
yields of Cs and Fr produced by a 1 GeV proton beam of the PNPI
synchrocyclotron and release properties of different targets have
been measured. Yields and release efficiencies of Cs and Fr
produced from a high density UC target material and from low
density UCx prepared by the ISOLDE method at IRIS in the
collaboration with PARRNe group from Orsay are compared. The
yields from ISOLDE original target are presented for comparison as
well. 相似文献
16.
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
17.
U. Köster O. Arndt R. Catherall J. G. Correia B. Crepieux R. Eichler P. Fernier L. M. Fraile S. Hennrich K. Johnston S. Lukic J. Neuhausen B. S. Nara Singh B. Pfeiffer E. Siesling 《The European physical journal. Special topics》2007,150(1):293-296
The production of ISOL beams of hafnium is described.
Radioactive Hf isotopes were produced at ISOLDE by 1.4 GeV proton-induced spallation
in Ta and W foils. Chemical evaporation in form of HfF4 and mass separation in the
molecular sideband HfF3+ after electron impact ionization provided intense
and pure beams.
Beams of 158-185Hf and short-lived isomers down to 1.1 s 177mHf were
observed, but the method could be extended to reach even more exotic isotopes:
down to about 154Hf (N=82) on the neutron-deficient side and up to
neutron-rich 188Hf. 相似文献
18.
U. Köster P. Carbonez A. Dorsival J. Dvorak R. Eichler S. Fernandes H. Frånberg J. Neuhausen Z. Novackova R. Wilfinger A. Yakushev 《The European physical journal. Special topics》2007,150(1):285-291
Refractory elements, i.e. elements with very high melting point and
low vapor pressure, cannot be released in atomic form from an ISOL target.
Therefore most of these elements are presently not available as ISOL beams.
However, when reactive gases are introduced
into the target, they may form volatile compounds with the refractory elements,
allowing for an easier transport to the ion source. Particularly useful are
high-temperature stable fluorides and oxides.
By these chemical evaporation methods so far ISOL beams of the refractory elements
C, Zr, Hf and Ta have been produced. We discuss how ISOL beams of B, Ti, Nb, Mo, Tc,
Ru, W, Re, Os and Ir could be produced in a similar way. 相似文献
19.
U. Leinberger E. Berdermann F. Heine S. Heinz O. Joeres P. Kienle I. Koenig W. Koenig C. Kozhuharov A. Schröter H. Tsertos C. Hofmann G. Soff 《The European Physical Journal A - Hadrons and Nuclei》1998,1(3):249-256
We present the first energy and angle resolved measurements of e+e−-pairs emitted from heavy nuclei (Z≥ 40) at rest by internal pair conversion (IPC) of transitions with energies of less than 2 MeV as well as recent theoretical
results using the DWBA method, which takes full account of relativistic effects, magnetic substates and finite size of the
nucleus. The 1.76 MeV E0 transition in 90Zr (90Sr source) and the 1.77 MeV M1 transition in 207Pb (207Bi source) have been investigated experimentally using the essentially improved setup at the double-ORANGE β-spectrometer
of GSI. The measurements prove the capability of the setup to cleanly identify the IPC pairs in the presence of five orders
of magnitude higher β− and γ background from the same source and to yield essentially background-free sum spectra despite the large background.
Using the ability of the ORANGE setup to directly determine the opening angle of the e+e−–pairs (Θe+e−), the angular correlation of the emitted pairs was measured within the range covered experimentally (40°≤Θe+e−≤ 180°). In the 90Zr case the correlation could be deduced for a wide range of energy differences E
Δ of the pairs (−530 keV ≤E
Δ≤ 530 keV). The 90Zr results are in good agreement with recent theory. The angular correlation deduced for the M1 transition in 207Pb is in strong disagreement with theoretical predictions derived within the Born approximation and shows almost isotropic
character. This is again in agreement with the new theoretical results.
Received: 22 April 1997 / Revised version: 16 December 1997 相似文献
20.
M. Re G. Cuttone L. Celona F. Chines E. Messina D. Rizzo F. Tudisco V. Scuderi 《The European physical journal. Special topics》2007,150(1):303-306
The EXCYT facility at the INFN-LNS is based on a K-800
superconducting cyclotron delivering stable ion beams on a Target
Ion Source (TIS) assembly to produce the required nuclear species,
and on a 15 MV Tandem for post-accelerating the radioactive beams.
For some ion beams such as for Li, the extraction efficiency from
the TIS is higher when obtained by positive ionisation, while the
injection into the Tandem is possible only after a charge exchange
to obtain negative ions. In this work we present the procedures
together with the results of the production of 6,7,8,9Li beams extracted at EXCYT during the last year. The
production of the radioactive elements was performed by sending a
13C4+ primary beam of 45 MeV/u on a graphite target. The
ionisation of the production species was achieved by a tungsten
positive surface ioniser. The Li+ has been extracted from TIS
at different energies to cross-check the transmission and the
charge exchange efficiency. To perform the conversion from
positive to negative ions we employed a Charge Exchange Cell (CEC)
containing Cs vapours. The Li beam interacts with the latter in a
two-step reaction, thus converting its charge from +1 to –1. The
CEC was already characterised during off-line tests; the results
obtained at EXCYT confirmed both the isotopic shift effect and the
efficiency values at several given extraction energies. Future
improvements of the TIS and the CEC are discussed. 相似文献