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1.
A. Kellerbauer G. Bollen J. Dilling S. Henry F. Herfurth H.-J. Kluge E. Lamour D. Lunney R.B. Moore C. Scheidenberger S. Schwarz G. Sikler J. Szerypo 《Hyperfine Interactions》2001,132(1-4):507-511
With the Penning trap mass spectrometer ISOLTRAP, close to 200 nuclides have already been investigated and their masses determined
with a typical relative precision of δm/m=10−7. Recently, ISOLTRAP's beam preparation system was replaced by an RFQ ion beam cooler and buncher. The principle and the characteristics
of this new beam preparation system will be presented. It is planned to use ions of various carbon clusters C+
n
(n>1) as reference ions for mass measurements. Apart from negligible molecular binding energies, these clusters have masses
that are exact multiples of the unified atomic mass unit. This will allow ISOLTRAP to carry out absolute mass measurements
as well as to investigate possible mass-dependent systematic errors. The results of tests of the production, transport, and
trapping of such carbon clusters will be presented.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
Kellerbauer A. Blaum K. Bollen G. Herfurth F. Kluge H.-J. Kuckein M. Sauvan E. Scheidenberger C. Schweikhard L. 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(1):53-64
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
3.
F. Herfurth A. Kellerbauer F. Ames G. Audi D. Beck K. Blaum G. Bollen O. Engels H.-J. Kluge D. Lunney R.B. Moore M. Oinonen E. Sauvan C. Scheidenberger S. Schwarz G. Sikler C. Weber 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):17-20
Mass measurements of 34Ar, 73-78Kr, and 74,76Rb were performed with the Penning-trap mass spectrometer ISOLTRAP. Very accurate Q
EC-values are needed for the investigations of the
t-value of 0+ → 0+ nuclear β-decays used to test the standard model predictions for weak interactions. The necessary accuracy on the Q
EC-value requires the mass of mother and daughter nuclei to be measured with δm/m ⩽ 3 . 10-8. For most of the measured nuclides presented here this has been reached. The 34Ar mass has been measured with a relative accuracy of 1.1 . 10-8. The Q
EC-value of the 34Ar 0+ → 0+ decay can now be determined with an uncertainty of about 0.01%. Furthermore, 74Rb is the shortest-lived nuclide ever investigated in a Penning trap.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: frank.herfurth@cern.ch 相似文献
4.
K. Blaum D. Beck G. Bollen P. Delahaye C. Guénaut F. Herfurth A. Kellerbauer H.-J. Kluge U. Köster D. Lunney S. Schwarz L. Schweikhard C. Yazidjian 《Hyperfine Interactions》2005,162(1-4):173-179
We have demonstrated for the first time that element-selective laser ionization in combination with ultra-high resolution
mass spectrometry can be used to prepare isomerically pure ion ensembles. Together with β–γ coincidence studies this method allowed a determination of the low-energy structure and the unambiguous identification of
triple β-decaying isomerism in 70Cu. By selective resonant ionization and measurement of the masses of these three states using ISOLTRAP at ISOLDE/CERN with
a relative uncertainty of δm/m ≈ 5 ⋅ 10−8 a clear state-to-mass assignment was possible which resolved the assignment puzzle in 70Cu. 相似文献
5.
I. Dillmann M. Hannawald U. Köster V.N. Fedoseyev A. Wöhr B. Pfeiffer D. Fedorov J. Shergur L. Weissman W.B. Walters K.-L. Kratz 《The European Physical Journal A - Hadrons and Nuclei》2002,13(3):281-284
Production yields and β-decay half-lives (T
1/2) of very neutron-rich indium isotopes were determined at CERN/ISOLDE using isobaric selectivity of a resonance-ionization
laser ion-source. Beta-delayed neutron (βdn) multiscaling measurements have yielded improved T
1/2 for 206(6) ms 132In, 165(3) ms 133In and 141(5) ms 134In. With 92(10) ms 135In, a new r-process nuclide has been identified which acts as an important “waiting point” in the In isotopic chain for neutron
densities in the range n
n≃ 1024-1026 n/cm3, where the r-matter flow has already passed the A≃ 130 abundance peak region.
Received: 17 January 2002 / Accepted: 30 January 2002 相似文献
6.
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
7.
J. Dilling G. Audi D. Beck G. Bollen F. Herfurth A. Kellerbauer H.-J. Kluge D. Lunney R.B. Moore C. Scheidenberger S. Schwarz G. Sikler J. Szerypo 《Hyperfine Interactions》2001,132(1-4):329-333
The masses of the xenon isotopes with 114≤A≤123 were directly measured for the first time. The experiments were carried out at the ISOLTRAP triple trap spectrometer
at the on-line mass separator ISOLDE/CERN. A mass resolving power of the Penning trap spectrometer of m/Δm≈500 000 was chosen and an accuracy of δm≈12keV for all investigated Xe isotopes was achieved. An atomic mass evaluation was performed and the results of this adjustment
are compared with theoretical predictions. The new results for the xenon isotopes and their effects on neighboring nuclides
are discussed within the two-neutron separation energy picture.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
F. Le Blanc L. Cabaret J.E. Crawford S. Essabaa V. Fedoseyev W. Geithner J. Genevey M. Girod R. Horn G. Huber S. Kappertz J. Lassen J.K.P. Lee G. Le Scornet V. Mishin R. Neugart J. Obert J. Oms A. Ouchrif S. Peru J. Pinard H. Ravn B. Roussière J. Sauvage D. Verney 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):49-51
Laser spectroscopy measurements have been carried out on the very neutron-rich tin isotopes with the COMPLIS experimental
setup. Using the 5s
25p
23
P
0 → 5s
25p6s
3
P
1 optical transition, hyperfine spectra of 126-132Sn and 125m, 127m, 129m-131mSn where recorded for the first time. The variation of the mean-square charge radius ( δ〈r
2〉) between these nuclei and nuclear moments of the isomers and the odd isotopes were thus measured. An odd-even staggering
which inverts at A = 130 is clearly observed. This indicates a small appearance of a plateau on the δ〈r
2〉 which has to be confirmed by measuring the isotope shift beyond A = 132.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: leblanc@ipno.in2p3.fr 相似文献
9.
H. Naik R.J. Singh R.H. Iyer 《The European Physical Journal A - Hadrons and Nuclei》2003,16(4):495-507
Charge distribution studies for heavy-mass fission products were carried out in the fast-neutron-induced fission of 232Th, 238U, 240Pu and 244Cm using radiochemical and gamma-ray spectrometric techniques. The width parameter( σZ/σA), the most probable charge/mass ( Z
P/A
P), the charge polarization (ΔZ) and the slope of charge polarization [ δ(ΔZ)/δA
′] as a function of the fragment mass (A
′) were deduced. The average charge dispersion parameter ( 〈σZ〉) and proton odd-even effect ( δp) were also obtained for these fissioning systems. The 〈σZ〉 and δp values in the fissioning systems 241Pu * and 245Cm * were determined for the first time. The δ(ΔZ)/δA
′ value is also determined for the first time in the fissioning systems 239U * , 241Pu * and 245Cm * . These data along with the literature data for even-Z fissioning systems such as 230Th * , 232Th * , 233U * , 234U * , 236U * , 238U * , 239Pu * , 240Pu*, 242Pu * , 246Cm * , 250Cf * and 252Cf(SF) are discussed in terms of nuclear structure effect and dynamics of descent from the saddle to the scission point. The
role of the excitation energy in low-energy fission is also discussed.
Received: 26 July 2002 / Accepted: 3 December 2002 / Published online: 3 April 2003
RID="a"
ID="a"Present address: Emeritus Scientist (CSIR) Bhabha Atomic Research Centre, Nuclear Recycle Group, WIP Building, Trombay, Mumbai-400085, India;
e-mail: rhiyer@magnum. barc.ernet.in
Communicated by D. Schwalm 相似文献
10.
D. Beck F. Ames G. Audi G. Bollen F. Herfurth H. -J. Kluge A. Kohl M. König D. Lunney I. Martel R. B. Moore H. Raimbault-Hartmann E. Schark S. Schwarz M. de Saint Simon J. Szerypo 《The European Physical Journal A - Hadrons and Nuclei》2000,8(3):307-329
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
11.
P. Mélinon F. Tournus B. Masenelli A. Perez M. Pellarin J. Lermé M. Broyer B. Champagnon 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):337-340
This paper deals with a new type of SiC bonding where silicon atom seems to bridge C60 molecules. We have studied films obtained by deposition of (C60)nSim clusters prepared in a laser vaporization source. Prior deposition, free ionized clusters were studied in a time-of-flight
mass spectrometer. Mixed clusters (C60)nSim were clearly observed. Abundance and photofragmentation mass spectroscopies revealed the relatively high stability of the
(C60)nSi
n
+
, (C60)nSi
n - 1
+
and (C60)nSi
n - 2
+
species. This observation is in favor of the arrangement of these complexes as polymers where the C60 cages may be bridged by a silicon atom. Free neutral clusters are then deposited onto substrate making up a nanogranular
thin film (≃ 100 nm). The film is probed by Auger and X-ray photoemission spectroscopies, but above all by surface enhanced Raman scattering.
The results suggest an unusual chemical bonding between silicon and carbon and the environment of the silicon atom is expected
to be totally different from the sp3 lattice: ten or twelve carbon neighbors might surround silicon atom. The bonding is discussed to the light of the so-called
fullerene polymerization as observed for pure fullerite upon laser irradiation. This opens a new route for bridging C60 molecules together with an appreciable energy bonding, since the usual van der Waals bonding in fullerite could be replaced
by an ionocovalent bond. Such an assumption must be checked in the future by XAS and EXAFS experiments.
Received 15 November 2000 相似文献
12.
Jesús?álvarez-Ruiz Marien?López-Arias Rebeca?de?Nalda Margarita?Martín Andrés?Arregui Luis?Ba?ares 《Applied Physics A: Materials Science & Processing》2009,95(3):681-687
The formation of cationic clusters in the laser ablation of CdS targets has been investigated as a function of wavelength
and fluence by mass spectrometric analysis of the plume. Ablation was carried out at the laser wavelengths of 1064, 532, 355,
and 266 nm in order to scan the interaction regimes below and above the energy band gap of the material. In all cases, the
mass spectra showed stoichiometric Cd
n
S
n
+ and nonstoichiometric Cd
n
S
n−1+, Cd
n
S
n+1+, and Cd
n
S
n+2+ clusters up to 4900 amu. Cluster size distributions were well represented by a log-normal function, although larger relative
abundance for clusters with n=13, 16, 19, 34 was observed (magic numbers). The laser threshold fluence for cluster observation was strongly dependent on
wavelength, ranging from around 16 mJ/cm2 at 266 nm to more than 300 mJ/cm2 at 532 and 1064 nm. According to the behavior of the detected species as a function of fluence, two distinct families were
identified: the “light” family containing S2+ and Cd+ and the “heavy” clusterized family grouping Cd2+ and Cd
n
S
m
+. In terms of fluence, it has been determined that the best ratio for clusterization is achieved close to the threshold of
appearance of clusters at all wavelengths. At 1064, 532, and 355 nm, the production of “heavy” cations as a function of fluence
showed a maximum, indicating the participation of competitive effects, whereas saturation is observed at 266 nm. In terms
of relative production, the contribution of the “heavy” family to the total cation signal was significantly lower for 266 nm
than for the longer wavelengths. Irradiation at 355 nm in the fluence region of 200 mJ/cm2 has been identified as the optimum for the generation of large clusters in CdS. 相似文献
13.
M. Bender T. Cornelius G.A. Lalazissis J.A. Maruhn W. Nazarewicz P.-G. Reinhard 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):23-28
Recent mass measurements show a substantial weakening of the binding-energy difference δ2p(Z, N) = E(Z - 2, N) - 2E(Z, N) + E(Z + 2, N) in the neutron-deficient Pb isotopes. As δ2p is often attributed to the size of the proton magic gap, it might be speculated that reduction in δ2p is related to a weakening of the spherical Z = 82 shell. We demonstrate that the observed trend is described quantitatively by self-consistent mean-field models in terms
of deformed ground states of Hg and Po isotopes.
Received: 25 October 2001 / Accepted: 28 February 2002 相似文献
14.
M. Mukherjee D. Beck K. Blaum G. Bollen J. Dilling S. George F. Herfurth A. Herlert A. Kellerbauer H. -J. Kluge S. Schwarz L. Schweikhard C. Yazidjian 《The European Physical Journal A - Hadrons and Nuclei》2008,35(1):1-29
ISOLTRAP is a Penning trap mass spectrometer for high-precision mass measurements on short-lived nuclides installed at the
on-line isotope separator ISOLDE at CERN. The masses of close to 300 radionuclides have been determined up to now. The applicability
of Penning trap mass spectrometry to mass measurements of exotic nuclei has been extended considerably at ISOLTRAP by improving
and developing this double Penning trap mass spectrometer over the past two decades. The accurate determination of nuclear
binding energies far from stability includes nuclei that are produced at rates less than 100 ions/s and with half-lives well
below 100ms. The mass-resolving power reaches 107 corresponding to 10keV for medium heavy nuclei and the uncertainty of the resulting mass values has been pushed down to below
10-8. The article describes technical developments achieved since 1996 and the present performance of ISOLTRAP. 相似文献
15.
C. Bobbert C.P. Schulz 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):95-97
Nam(H2O)n Clusters ( n = 1...200, m = 1...50) are formed in a recently build pick-up arrangement. Preformed water clusters traverse a sodium oven, where sodium
atoms are picked up. At low sodium vapour pressure ( < 1×10-4 mbar) pure Na(H2O)n clusters are observed in the mass spectra. At high sodium vapour pressure ( > 1×10-3 mbar) the water cluster pick up more than 50 Na atoms and reaction products Na(NaOH)n ( n = 2, 4...50) dominate the mass spectra. The even number of NaOH units in the products indicate that also in a finite cluster
the reaction occurs in pairs as in the macroscopic reaction.
Received 4 December 2000 相似文献
16.
T. Schlathölter M.W. Newman T.R. Niedermayr G.A. Machicoane J.W. McDonald T. Schenkel R. Hoekstra A.V. Hamza 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(2):323-327
The emission of small (hydrogenated) carbon cluster ions CnHm
+
(n
=2-22) upon highly charged Xeq+ (q
=20-44) impact on C84 surfaces is studied by means of time-of-flight secondary ion mass spectrometry. The respective stage of hydrogenation/protonation
of a certain carbon cluster ion Cn
+
is a strong indication for its geometrical structure. From the cluster ion yield as a function of cluster size it can be
concluded, that the hydrogenation takes place after the initial carbon cluster formation. The carbon clusters seem to be emitted
as an entity in agreement with “equilibrium” and “shock wave” models.
Received 4 February 2000 相似文献
17.
We present the first photoacoustic spectrometer for gas sensing employing both the fundamental and the frequency-doubled radiation
of a continuously tunable high-pressure CO2 laser with room temperature operation. A quasi-phase-matched diffusion-bonded GaAs crystal is used in the system for second-harmonic
generation. A pulsed photoacoustic detection scheme with a non-resonant cell, equipped with an 80-microphone array, is employed.
The wide continuous tuning range in the fundamental (9.2–10.7 μm) and the frequency-doubled (4.6–5.35 μm) regimes, together
with the narrow linewidth of 540 MHz (0.018 cm-1) for the 10-μm region and of 1050 MHz (0.0315 cm-1) for the 5-μm region, allow the measurement of gas mixtures, individual species and isotope discrimination. This is illustrated
with measurements on NO and CO2. The measured isotope ratio 15
NO/14
NO=(3.58±0.55)×10-3 agrees well with the literature (3.700×10-3) and demonstrates the good selectivity of the system.
Received: 30 April 2002 / Revised version: 10 June 2002 / Published online: 2 September 2002
RID="*"
ID="*"Corresponding author. Fax: +41-1/633-1077, E-mail: sigrist@iqe.phys.ethz.ch 相似文献
18.
A. Chaudhuri M. Block S. Eliseev R. Ferrer F. Herfurth A. Martín G. Marx M. Mukherjee C. Rauth L. Schweikhard G. Vorobjev 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,45(1):47-53
A carbon-cluster ion source has been installed and tested
at SHIPTRAP, the Penning-trap mass spectrometer for precision mass
measurements of heavy elements at GSI. Carbon-cluster ions
12Cn
+, 5 ≤n ≤23, were produced by
laser-induced desorption and ionization from
a
carbon sample. They
were tested for the first time as reference ions in an on-line mass
measurement of the radionuclides 144Dy, 146Dy and
147Ho. In addition, carbon clusters of various sizes were used
for an investigation of the systematic uncertainty of SHIPTRAP
covering a mass range from 84 u to 240 u. The mass-dependent
uncertainty was found to be negligible for the case of
(m-m ref)< 100 u. However, a systematic uncertainty of 4.5
×10-8 was revealed. 相似文献
19.
J. L. Deng K. H. Su X. Wang Q. F. Zeng L. F. Cheng Y. D. Xu L. T. Zhang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,49(1):21-35
The most stable structures of gaseous Si
m
C
n
(3 ⩽ n+m ⩽ 6) clusters in their ground electronic states are determined with the high level electronic correlation method QCISD(T)/g3large.
Thermodynamic properties on heat capacity (C
p,m
Θ), entropy (S
m
Θ), Gibbs energy function (−[G
Θ −H
Θ(T
r
)]/T) and enthalpy function (H
Θ−H
Θ(T
r
)) are predicted with standard statistical thermodynamics using the structure parameters and vibrational frequencies obtained
with B3PW91/6-31G(d) method combined with the electronic excitation energies determined with time dependent density functional (TD DFT) method
at B3PW91/6-31G(d) level. The electronic energies are calculated with the accurate model chemistry method at G3(QCI) level of theory and the
Δ
f
H
m
Θ (0 K), Δ
f
H
m
Θ (298.15 K) and Δ
f
G
m
Θ (298.15 K) values are predicted. The heat capacities C
p,m
Θ(T) as a function of temperature within 298.15-2000 K are fitted into analytical equations. The thermodynamic functions at higher
temperatures are determined classically by using these equations. Most of the results obtained in this work are consistent
with the available experiments. 相似文献
20.
A. Qayyum M.N. Akhtar 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(1):181-184
Light emission during sputtering of graphite targets with 1–10 keV Ne+, Kr+ and Xe+ beams has been investigated in the 180-600 nm wavelength range. Beside the characteristic lines of sputtered C1 and C1
+, a continuum superimposed with a number of broad structures was observed in the 250-520 nm range, and having a maximum at
386 nm. Mass analysis of the sputtered flux confirmed the presence of negative carbon clusters C
m
-
, C2
- being the dominant one. Ion beam parameters i.e. ion mass, energy, current density and ion dose were varied to identify the origin of the continuum emission. On the basis
of the experimental results, it is suggested that the continuum is predominantly due to the overlapping of various band systems
of sputtered C2 with a small contribution from the heavier sputtered carbon clusters Cm (m>2).
Received 24 September 1999 and Received in final form 11 February 2000 相似文献