共查询到20条相似文献,搜索用时 562 毫秒
1.
S. Schwarz C. Bachelet M. Block G. Bollen D. Davies M. Facina C. M. Folden III C. Guénaut J. Huikari E. Kwan A. A. Kwiatkowski D. J. Morrissey G. Pang A. Prinke R. Ringle J. Savory P. Schury C. Sumithrarachchi T. Sun 《Hyperfine Interactions》2006,173(1-3):113-122
The low-energy beam and ion trap facility LEBIT at the NSCL at MSU has demonstrated that rare isotopes produced by fast-beam
fragmentation can be slowed down and prepared such that precision experiments with low-energy beams are possible. For this
purpose high-pressure gas-stopping is employed combined with advanced ion manipulation techniques. Penning trap mass measurements
on short-lived rare isotopes have been performed with a 9.4 T Penning trap mass spectrometer. Examples include 66As, which has a half-live of only 96 ms, and the super-allowed Fermi-emitter 38Ca, for which a mass accuracy of 8 ppb (280 eV) has been achieved. The high accuracy of this new mass value makes 38Ca a new candidate for the test of the conserved vector current hypothesis.
相似文献
2.
G. Bollen C. Bachelet M. Block D. A. Davies M. Facina C. M. Folden III C. Guénaut J. Huikari E. Kwan A. Kwiatowski D. J. Morrissey G. Pang A. Prinke R. Ringle J. Savory P. Schury S. Schwarz C. Sumithrarachchi T. Sun 《The European physical journal. Special topics》2007,150(1):337-341
The Low-Energy Beam and Ion Trap facility LEBIT at the
NSCL at MSU has demonstrated that rare isotopes produced by
fast-beam fragmentation can be slowed down and prepared for
precision experiments with low-energy beams. High-pressure
gas-stopping was combined with advanced ion manipulation techniques
to carry out these studies with a high-precision 9.4-Tesla Penning
trap mass spectrometer. The spectrometer has been used for a series
of high precision mass measurements of short-lived neutron- and
proton-rich isotopes during the past year. This paper presents an
overview of the LEBIT facility and summarizes the first mass
measurement results. The mass measurements of 81Se, where
ground and isomeric states have been resolved, and of 80As will
be discussed in detail. 相似文献
3.
M. Redshaw B. R. Barquest G. Bollen S. E. Bustabad C. M. Campbell R. Ferrer A. Gehring A. A. Kwiatkowski D. L. Lincoln D. J. Morrissey G. K. Pang R. Ringle S. Schwarz 《Hyperfine Interactions》2011,199(1-3):241-249
The LEBIT (Low Energy Beam and Ion Trap) facility is the only Penning trap mass spectrometry (PTMS) facility to utilize rare isotopes produced via fast-beam fragmentation. This technique allows access to practically all elements lighter than uranium, and in particular enables the production of isotopes that are not available or that are difficult to obtain at isotope separation on-line facilities. The preparation of the high-energy rare-isotope beam produced by projectile fragmentation for low-energy PTMS experiments is achieved by gas stopping to slow down and thermalize the fast-beam ions, along with an rf quadrupole cooler and buncher and rf quadrupole ion guides to deliver the beam to the Penning trap. During its first phase of operation LEBIT has been very successful, and new developments are now underway to access rare isotopes even farther from stability, which requires dealing with extremely short lifetimes and low production rates. These developments aim at increasing delivery efficiency, minimizing delivery and measurement time, and maximizing use of available beam time. They include an upgrade to the gas-stopping station, active magnetic field monitoring and stabilization by employing a miniature Penning trap as a magnetometer, the use of stored waveform inverse Fourier transform (SWIFT) to most effectively remove unwanted ions, and charge breeding. 相似文献
4.
G. Savard R. C. Pardo S. Baker C. N. Davids A. Levand D. Peterson D. G. Phillips T. Sun R. Vondrasek B. J. Zabransky G. P. Zinkann 《Hyperfine Interactions》2011,199(1-3):301-309
The Californium Rare Ion Breeder Upgrade (CARIBU) to the ATLAS superconducting linac facility is currently being commissioned. It provides low-energy and re-accelerated beams of neutron-rich isotopes obtained from 252Cf fission. The fission products from a 252Cf source are stopped in a large high-intensity gas catcher, thermalized and extracted through an RFQ cooler, accelerated to 50 kV and mass separated in a high-resolution separator before being sent to either an ECR charge breeder for post-acceleration through the ATLAS linac or to a low-energy experimental area. This approach gives access to beams of very neutron-rich isotopes, many of which have not been available at low or Coulomb barrier energies previously. These beams provide unique opportunities for measurements along the r-process path. To take advantage of these unique possibility, the reaccelerated beams from CARIBU will be made available at the experimental stations of ATLAS to serve equipment such as Gammasphere, HELIOS and the reaction spectrometers. In addition, the Canadian Penning Trap (CPT) mass spectrometer has been moved to the CARIBU low-energy experimental area and a new injection line has been built. The new injection line consists of a RFQ buncher sitting on a 50 kV high-voltage platform that will accumulate the mass separated 50 kV radioactive beams, cool and extract them as a pulsed beam of 3 keV. This beam can be sent either to a tape station for diagnostics and tuning, or a cryogenic linear trap for preparation before transfer to the high-precision Penning trap where the mass measurements will take place. Initial CARIBU commissioning is proceeding with a 2 mCi source that will be replaced by a 100 mCi source as the commissioning proceeds. Final operation will use a 1 Ci source and attain yield in excess of 107 ions/sec for the most intense beams at low energy, an order of magnitude less for reaccelerated beams. 相似文献
5.
P. Schury G. Bollen M. Block D. J. Morrissey R. Ringle A. Prinke J. Savory S. Schwarz T. Sun 《Hyperfine Interactions》2006,173(1-3):165-170
A linear gas stopping cell has been implemented at the NSCL as part of the Low Energy Beam and Ion Trap (LEBIT) facility.
The gas stopping cell is used to convert relativistic ions into low energy ions suitable for use in ion trap experiments.
A common undesired property of such systems is the production of beam contaminants through charge exchange of gas impurities
with the He + ions produced in the stopping process. These contaminants are of particular concern for Penning trap mass spectrometry, where
the simultaneous trapping of ions with different masses can cause unwanted shifts in the measured cyclotron frequency of the
desired ions. In order to minimize such effects, a multi-stage beam purification system has been implemented at LEBIT. 相似文献
6.
S. Rinta-Antila T. Eronen V. -V. Elomaa U. Hager J. Hakala A. Jokinen P. Karvonen H. Penttilä J. Rissanen T. Sonoda A. Saastamoinen J. Äystö 《The European Physical Journal A - Hadrons and Nuclei》2007,31(1):1-7
A new technique to produce isobarically pure ion beams for decay spectroscopy by using a gas-filled Penning trap was commissioned
at the ion guide isotope separator on-line facility, IGISOL. β-decays of neutron-rich 100Zr, 102Zr and 104Zr isotopes were studied with this technique. In addition, the
values of 100,102,104Zr β-decays were determined from the direct mass measurements of zirconium and niobium isotopes performed with a high-precision
Penning trap. The mass of 104Nb was directly measured for the first time and the obtained mass excess value for the longer-living (1+) state is -71823±10 keV. For the ground states of 100Nb and 102Nb the obtained mass excess values were -79802±20 keV and -76309±10 keV, respectively. The observed distribution of the β
strength supports a prolate deformation assignment for 100,102,104Zr isotopes. 相似文献
7.
P. Delheij L. Blomeley M. Froese G. Gwinner V. Ryjkov M. Smith J. Dilling 《Hyperfine Interactions》2006,173(1-3):123-131
The TITAN facility at TRIUMF-ISAC will use four ion traps with the primary goal of determining nuclear masses with high precision, particularly for short lived isotopes with lifetimes down to approximately 10 ms. The design value for the accuracy of the mass measurement is 1 ×10???8. The four main components in the facility are an RF cooler/buncher (RFCT) receiving the incoming ion beam, an electron beam ion trap (EBIT) to breed the ions to higher charge states, a cooler Penning trap (CPET) to cool the highly charged ions, and finally the measurement Penning trap (MPET) for the precision mass determination. Additional goals for this system are laser spectroscopy on ions extracted from the RFCT and beta spectroscopy in the EBIT (in Penning trap mode) on ions that are purified using selective buffer gas cooling in the CPET. The physics motivation for the mass measurements are manifold, from unitarity tests of the CKM matrix to nuclear structure very far from the valley of stability, nuclear astrophysics and the study of halo-nuclei. As a first measurement the mass of 11Li will be determined. With a lifetime of 8.7 ms and a demonstrated production rate of 4×104 ions/sec at ISAC the goal for this measurement at TITAN is a relative uncertainty of 5×10???8. This would check previous conflicting measurements and provide information for nuclear theory and models. 相似文献
8.
The excitation of the motion of ions in a Penning trap at twice their cyclotron frequency, 2ν
c
, by means of an azimuthal octupolar RF field has been studied with the LEBIT facility at the NSCL. The possibility of such
an RF octupolar excitation has been verified. Compared to ion excitation at ν
c
by means of quadrupolar fields an increased resolving power is observed in the cyclotron resonance curves, which may have
important implications for Penning trap mass measurements. Numerical simulations have been used to characterize important
properties of this type of excitation in detail and to predict the behavior of the ion motion under realistic conditions.
Good agreement with the experimental results is observed.
相似文献
9.
V. V. Simon P. Delheij J. Dilling Z. Ke W. Shi G. Gwinner 《Hyperfine Interactions》2011,199(1-3):151-159
TITAN is an on-line facility dedicated to precision experiments with short-lived radioactive isotopes, in particular mass measurements. The achievable resolution on mass measurement, which depends on the excitation time, is limited by the half life of the radioactive ion. One way to bypass this is by increasing the charge state of the ion of interest. TITAN has the unique capability of charge-breeding radioactive ions using an electron-beam ion trap (EBIT) in combination with Penning trap mass spectrometry. However, the breeding process leads to an increase in energy spread, ??E, which in turn negatively influences the mass uncertainty. We report on the development of a cooler Penning trap which aims at reducing the energy spread of the highly charged ions prior to injection into the precision mass measurement trap. Electron and proton cooling will be tested as possible routes. Mass selective cooling techniques are also envisioned. 相似文献
10.
D. Beck F. Ames G. Audi G. Bollen H.-J. Kluge A. Kohl M. König I. Martel D. Lunney R.B. Moore H. Raimbault-Hartmann M. de Saint Simon E. Schark S. Schwarz J. Szerypo the ISOLDE Collaboration 《Hyperfine Interactions》1997,108(1-3):219-225
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
11.
F. Ames P. Schmidt O. Forstner G. Bollen O. Engels D. Habs G. Huber 《Hyperfine Interactions》2001,132(1-4):465-468
The beam quality of radioactive ion beams produced by present target ion source technology is often not sufficient for direct
post-acceleration. Furthermore, pulsed beams insure a more efficient use of an accelerator. In the case of REX-ISOLDE, the
post accelerator at the CERN ISOLDE facility, a gas-filled Penning trap (REXTRAP) has been chosen for accumulation of the
radioactive ions and conversion into cooled bunches. Radial centering of the ions is achieved by applying an rf field with
a frequency equal to the cyclotron frequency of the desired ion species. The efficiency achieved in the first tests with different
isotopes covering nearly the entire mass range was already >20%. Going to total numbers of >105 stored ions in the trap a shift of the centering frequency could be observed, which is most likely due to space charge effects.
Despite this, it was possible to accumulate up to 107 ions and deliver them as cooled bunches.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
Ettenauer S Simon MC Gallant AT Brunner T Chowdhury U Simon VV Brodeur M Chaudhuri A Mané E Andreoiu C Audi G López-Urrutia JR Delheij P Gwinner G Lapierre A Lunney D Pearson MR Ringle R Ullrich J Dilling J 《Physical review letters》2011,107(27):272501
Penning trap mass measurements of short-lived nuclides have been performed for the first time with highly charged ions, using the TITAN facility at TRIUMF. Compared to singly charged ions, this provides an improvement in experimental precision that scales with the charge state q. Neutron-deficient Rb isotopes have been charge bred in an electron beam ion trap to q=8-12+ prior to injection into the Penning trap. In combination with the Ramsey excitation scheme, this unique setup creating low energy, highly charged ions at a radioactive beam facility opens the door to unrivaled precision with gains of 1-2 orders of magnitude. The method is particularly suited for short-lived nuclides such as the superallowed β emitter 74Rb (T(1/2)=65 ms). The determination of its atomic mass and an improved Q(EC) value are presented. 相似文献
13.
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
14.
M. Block D. Ackermann K. Blaum C. Droese M. Dworschak M. Eibach S. Eliseev T. Fleckenstein E. Haettner F. Herfurth F. P. He?berger S. Hofmann J. Ketelaer J. Ketter H. -J. Kluge G. Marx M. Mazzocco Yu. N. Novikov W. R. Pla? A. Popeko S. Rahaman D. Rodríguez C. Scheidenberger L. Schweikhard P. G. Thirolf G. K. Vorobyev C. Weber 《Hyperfine Interactions》2010,196(1-3):225-231
Penning traps are widely used for high-precision mass measurements of radionuclides related to nuclear astrophysics studies and the evolution of nuclear structure far away from stability. With the stopping of secondary beams in gas cells together with advanced ion-beam manipulation techniques their reach has been extended to rare isotopes of essentially all elements. The Penning trap mass spectrometer SHIPTRAP at GSI Darmstadt has recently demonstrated that even high-precision mass measurements of transfermium elements can be performed despite low production rates of only about one particle per second. This important milestone opens new perspectives for the study of superheavy elements with ion traps. 相似文献
15.
R. Ringle 《Hyperfine Interactions》2010,196(1-3):215-217
Collected here are all publications related to high-precision Penning trap mass measurements performed at LEBIT which were published from 2007 to 2009. 相似文献
16.
M. B. Gómez-Hornillos J. Rissanen J. L. Taín A. Algora K. L. Kratz G. Lhersonneau B. Pfeiffer J. Agramunt D. Cano-Ott V. Gorlychev R. Caballero-Folch T. Martínez L. Achouri F. Calvino G. Cortés T. Eronen A. García M. Parlog Z. Podolyak C. Pretel E. Valencia 《Hyperfine Interactions》2014,223(1-3):185-194
The study of β-delayed neutron emission plays a major role in different fields such as nuclear technology, nuclear astrophysics and nuclear structure. However the quality of the existing experimental data nowadays is not sufficient for the various technical and scientific applications and new high precision measurements are necessary to improve the data bases. One key aspect to the success of these high precission measurements is the use of a very pure ion beam that ensures that only the ion of interest is produced. The combination of the IGISOL mass separator with the JYFLTRAP Penning trap is an excellent tool for this type of measurement because of the ability to deliver isobarically and even isomerically clean beams. Another key feature of the installation is the non-chemical selectivity of the IGISOL ion source which allows measurements in the important region of refractory elements. This paper summarises the β-delayed neutron emission studies that have been carried out at the IGISOL facility with two different neutron detectors based on 3He counters in a polyethylene moderator: the Mainz neutron detector and the BEta deLayEd Neutron detector. 相似文献
17.
We present a summary of precision atomic mass measurements of stable isotopes carried out at Florida State University. These include the alkalis 6Li, 23Na, 39,41K, 85,87Rb, 133Cs; the rare gas isotopes 84,86Kr and 129,130,132,136Xe; 17,18O, 19F, 28Si, 31P, 32S; and various isotope pairs of importance to neutrino physics, namely 74,76Se/74,76Ge, 130Xe/130Te, and 115In/115Sn. We also summarize our Penning trap measurements of the dipole moments of PH?+? and HCO?+?. 相似文献
18.
《Nuclear Physics A》1999,651(1):3-30
Direct mass measurements of short-lived Cs and Ba isotopes have been performed with the tandem Penning trap mass spectrometer ISOLTRAP installed at the on-line isotope separator ISOLDE at CERN. Typically, a mass resolving power of 600 000 and an accuracy of δm ≈ 13 keV have been obtained. The masses of 123,124,126Ba and 122mCs were measured for the first time. A least-squares adjustment has been performed and the experimental masses are compared with theoretical ones, particularly in the frame of a macroscopic-microscopic model. 相似文献
19.
Block M Bachelet C Bollen G Facina M Folden CM Guénaut C Kwiatkowski AA Morrissey DJ Pang GK Prinke A Ringle R Savory J Schury P Schwarz S 《Physical review letters》2008,100(13):132501
A new long-lived isomeric state in (65)Fe has been discovered with Penning trap mass spectrometry and high-precision mass measurements of the neutron-rich isotopes (63-65)Fe and (64-66)Co have been performed with the Low-Energy Beam and Ion Trap Facility at the NSCL. For the new isomer in (65)Fe an excitation energy of 402(5) keV has been determined from the measured mass difference between the isomeric and ground states. The mass uncertainties of all isotopes have been reduced by a factor of 10-100 compared to previous results. In the case of (64)Co the previous mass value was found to deviate by about 5 standard deviations from the new measurement. 相似文献
20.
K. Peräjärvi T. Eronen D. Gorelov J. Hakala A. Jokinen H. Kettunen V. Kolhinen M. Laitinen I. D. Moore H. Penttilä J. Rissanen A. Saastamoinen H. Toivonen J. Turunen J. Äystö 《Hyperfine Interactions》2014,223(1-3):239-243
Underground nuclear weapon detonations release gaseous species into the atmosphere. The most interesting isotopes/isomers from the detection point of view are 131mXe, 133mXe, 133Xe and 135Xe. We have developed a method that employs high-precision Penning trap mass spectrometry at the JYFLTRAP facility, the University of Jyväskylä, to produce pure calibration samples of these isotopes/isomers. Among developments this work required a new mass resolution record of a few parts-per-million. Here the status and future plans of the project are reviewed. 相似文献