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1.
R.?Wilfinger J.?Lettry the EURISOL?Task Workgroup 《The European physical journal. Special topics》2007,150(1):379-382
EURISOL foil-targets have to withstand a primary proton
beam of 1 GeV kinetic energy and up to 100 μA
beam current. These foil targets will be based on previous
high-power target concepts, i.e. the RIST target [J.R.J. Bennett et al.,
Nucl. Instrum. Meth. Phys. Res. B 126, 117 (1997)]
or high power targets used at
TRIUMF [P. Bricault et al.,
Nucl. Instrum. Meth. Phys. Res. B 204, 319 (2003), M. Dombsky et al.,
Nucl. Instrum. Meth. Phys. Res. B 204, 191 (2003)].
A single target unit is capable of dissipating up to 25 kW,
hence, several target units can be merged together by individual
transfer lines to one common ion source. The single target units
will be irradiated by a proton beam in a time sharing mode to
distribute the primary proton beam current to the individual
target units. In this feasibility study the necessary properties
of high-power foil targets are discussed and the requirements to
design a foil target according to the proton beam parameters
[CITE] for the future EURISOL facility
are given. 相似文献
2.
T. Uesaka T. Wakui S. Sakaguchi T. Kawahara H. Sakai 《The European physical journal. Special topics》2007,150(1):71-74
We have constructed a polarized proton solid target system for
radioactive nuclear beam experiments at the Center for Nuclear Study,
the University of Tokyo. The proton polarization is based on an electron
population difference in a photo-excited triplet state of pentacene
molecule. The target system was completed in 2003 and applied to a
RI beam experiment in 2003 and 2005 by using the projectile fragment
separator, RIPS at RIKEN. The maximum polarization reached
20% under the condition of T=100 K and B=0.09 T.
Overview of the polarized target and its application in physics
experiments at RIPS and RIBF of RIKEN are presented. 相似文献
3.
4.
F. Křížek V. Wagner J. Adam P. Čaloun V. Henzl D. Henzlová A. Krása A. Kugler M. Majerle M. I. Krivopustov V. I. Stegailov V. M. Tsoupko-Sitnikov 《Czechoslovak Journal of Physics》2006,56(3):243-252
The Neutron Activation Analysis Method was used to study neutron field in a setup consisting of a thick lead target and a
natural uranium blanket. This setup was exposed to 1.5 GeV proton beam from the Nuclotron accelerator. By means of gamma-ray
spectroscopic measurements we determined the yields of various nuclear reactions induced in the radio-chemical sensors. The
data obtained were then compared with the results of a MCNPX simulation. 相似文献
5.
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
6.
We analyze the left–right asymmetry of pion production in semi-inclusive deep inelastic scattering (SIDIS) process of unpolarized charged lepton on transversely polarized nucleon target. Unlike available treatments, in which some specific weighting functions are multiplied to separate theoretically motivated quantities, we do not introduce any weighting function following the analyzing method by the E704 experiment. The advantage is that this basic observable is free of any theoretical bias, although we can perform the calculation under the current theoretical framework. We present numerical calculations at both HERMES kinematics for the proton target and JLab kinematics for the neutron target. We find that with the current theoretical understanding, Sivers effect plays a key role in our analysis. 相似文献
7.
The proton radioactivity hMf-lives of spherical proton emitters are calculated by the cluster model with the con- tribution of a centrifugal potential barrier considered separately. The results are compared with the experimental data and other theoretical data, and good agreement is found for most nuclei. In addition, two formulae are pro- posed for the proton decay half-life of spherical proton emitters through the least squares fit to the experimental data available, and could reproduce the experimental half-lives successfully. 相似文献
8.
A. S. Tchakoutio Nguetcho P. B. Ndjoko T. C. Kofane 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,62(1):7-14
The proton conductivity and the mobility arising from motions of the
ionic and bonded defects, in hydrogen-bonded molecular systems are
investigated by means of the quantum mechanical method. Our two component
model goes beyond the usual classical harmonic interaction by inclusion of a
quartic interaction potential between the nearest-neighbor protons. Among
the rich variety of soliton patterns obtained in this model, we focus our
attention to compact kink (kinkon) solutions to calculate analytically, the
mobility of the kinkon-antikinkon pair and the specific
electrical-conductivity of the protons transfer in the hydrogen-bonded
systems under an externally applied electrical-field through the dynamic
equation of the kinkon-antikinkon pair. For ice, the mobility and the
electrical conductivity of the proton transfer obtained are about
5.307×10-7 m2 V-1 s-1
and 6.11×10-4 Ω-1 m-1, respectively. The results
obtained are in qualitative agreement with experimental data. 相似文献
9.
Planar Channelling Criticalities of MeV Protons in Si Crystal: Simulations, Evaluation and Applications 下载免费PDF全文
Mukhtar Ahmed Rana 《中国物理快报》2008,25(10):3724-3727
We reports a phase-space structure of MeV proton beam planar channelled along {110} planes in Si crystal using simulation results with the help of a computer code FLUX. The aim is to understand channelling conditions suitable for disorder measurement in crystals. Phase-space distribution of a planar channelled proton beam evolutes in a systematic fashion when it travels into the crystal. Planar channelled beam oscillates between phase-like and space-like conditions in which a part of the beam becomes under phase and space criticalities. These criticality conditions in planar channelling are analysed, explained and discussed with the perspective of defect measurement in crystals. 相似文献
10.
E. Rapisarda F. Amorini L. Calabretta G. Cardella M. De Napoli G. Raciti C. Sfienti 《The European physical journal. Special topics》2007,150(1):169-172
Two proton radioactivity studies have been performed on
excited states of 18Ne produced, among other fragments, by
20Ne projectile fragmentation and excited via Coulomb
excitation on a Pb target. Every incoming ion was tagged before
interacting with the lead target on an event by event basis in
order to discriminate the secondary reactions according to the
projectile. Decay of 18Ne levels has been studied by complete
kinematical reconstruction. In spite of the low statistics a
couple of events looks very promising for two proton correlated
emission. 相似文献
11.
H. Arenhövel 《The European Physical Journal A - Hadrons and Nuclei》2007,34(3):303-313
The influence of Coulomb distortion on the polarization transfer in elastic proton and antiproton electron scattering at low
energies is calculated in a distorted-wave Born approximation. For antiproton electron scattering Coulomb effects reduce substantially
the polarization transfer cross-section compared to the plane-wave Born approximation, whereas for proton electron scattering
they lead to a dramatic increase for kinetic proton lab energies below about 20keV. 相似文献
12.
R. Göring Zhan Yuan-Ling St. Steinberg 《Applied Physics A: Materials Science & Processing》1992,55(1):97-100
The photoconductivity and photovoltaic currents of pure LiNbO3 and proton exchanged waveguides in LiNbO3 have been measured as a function of the optical intensity up to about several kW/cm2 by the use of surface electrodes. For pure LiNbO3 the observed dependences are a simple extrapolation of the well known low intensity behaviour. The photoconductivity of proton exchanged waveguides is considerably increased compared with pure LiNbO3 and the curves are strongly nonlinear in the high intensity region. These results can explain, at least qualitatively, the previously observed characteristic time and intensity dependence of light-induced refractive index changes in this type of waveguides. Both the time and temperature behaviour of the dark conductivity of all proton exchanged waveguides give strong evidence of ionic charge transport in the proton exchanged region. 相似文献
13.
J.F. Liang J.R. Beene A.L. Caraley H. Esbensen A. Galindo-Uribarri C.J. Gross P.E. Mueller K.T. Schmitt D. Shapira D.W. Stracener R.L. Varner 《Physics letters. [Part B]》2009
Angular distributions of the Coulomb breakup of radioactive 17F were measured by impinging a 10 MeV/nucleon beam on 208Pb and on 58Ni to study the dynamic polarization effects. The breakup products, oxygen and a proton, were detected in coincidence. First-order perturbation theory significantly overpredicts the breakup cross section for the 208Pb target. Dynamical calculations with a dynamic polarization as the leading order correction were performed. The calculations reproduce the data for 17F on 58Ni but overpredict the breakup of 17F on 208Pb by a factor of two at forward angles. 相似文献
14.
In this work we investigate the rainbows appearing in channeling of 1 GeV protons through the long (11,9) single-wall carbon nanotubes. The nanotube length is varied from 10 to 500 μm. The angular distributions of channeled protons are computed using the numerical solution of the proton equations of motion in the transverse plane and the Monte Carlo method. The rainbows are identified as the rings in the angular distributions, which correspond to the extrema of the proton deflection functions. Each rainbow is characterized by a sharp decrease of the proton yield on its large angle side. As the nanotube length increases, the number of rainbows increases and the average distance between them decreases in an easily predictable way. When the average distance between the rainbows becomes smaller than the resolution of the angular distribution, one cannot distinguish between the adjacent rainbows, and the angular distribution becomes equilibrated. We call this route to equilibration the rainbow route to equilibration. This work is a demonstration of how a simple one-dimensional bound dynamic system can exhibit a complex collective behavior. 相似文献
15.
W. Klamra S. Asztalos J.A. Becker B. Cederwall R.M. Clark M.A. Deleplanque R.M. Diamond P. Fallon L.P. Farris I.Y. Lee A.O. Macchiavelli R.W. Macleod D.G. Sarantites F.S. Stephens 《The European Physical Journal A - Hadrons and Nuclei》2001,10(1):11-12
Studies by means of 155 MeV 27Al bombardment on a 130Te target revealed in 148Eu high-spin structures up to spin 31?, in addition to a cascade extended to the 11088.1 keV excitation. The observed levels
are tentatively assigned as complex multiparticle-hole proton and neutron configurations.
Received: 15 December 2000 / Accepted: 29 January 2001 相似文献
16.
H. Shu S.-Z. Fu X.-G. Huang M.-X. Ma J. Wu J.-J. Ye J.-H. He Y. Gu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(2):367-370
Using the ninth laser beam (converted to 2ω) of
“Shenguang-II” laser facility and the beam smoothing technology of
lens-array [Appl. Opt. 25, 377 (1986); Phys. Plasmas. 9, 3201 (1995)],
a shock wave with 700 μm (the root-mean-square of
shock breakout time (RMS) RMS ≈ 6.32 ps) flat top was created. An Al-Al
four-step target was designed to do research on shock wave stability in an
Al target. And the shock stability experiment with the Al-Al four-step
target indicated that the shock wave steadily propagated in the Al target of
thickness of about 20–45 μm under the power density of ~ 1.0×1014 W/cm2. 相似文献
17.
I. Savatinova S. Tonchev M. Kuneva 《Applied Physics A: Materials Science & Processing》1993,56(1):81-86
New results on Raman spectra of protonated LiNbO3 are reported in order to clarify the structural and compositional changes in waveguide layers during proton exchange and post-exchange annealing processes. Samples with different degree of Li-H substitution exchanged in either neat or buffered benzoic and pyrophosphoric acid melts are investigated providing Raman and optical measurements simultaneously. The question of phase state of protonated layers at slow and rapid cooling after the annealing procedure is discussed. Qualitative and quantitative agreement between the structural data reported earlier for proton-exchanged powders and the Raman data obtained for protonated single crystals is established. A new band at 69 cm–1 is observed which is strongly intensity dependent upon the hydrogen presence in waveguide layers. By using this band the degree of proton exchange is determined for different treatment conditions of the samples. 相似文献
18.
19.
T. Repsilber M. Borghesi J.-C. Gauthier K. Löwenbrück A. Mackinnon V. Malka P. Patel G. Pretzler L. Romagnani T. Toncian O. Willi 《Applied physics. B, Lasers and optics》2005,80(7):905-913
A method for obtaining quantitative information about electric field and charge distributions from proton imaging measurements
of laser-induced plasmas is presented. A parameterised charge distribution is used as target plasma. The deflection of a proton
beam by the electric field of such a plasma is simulated numerically as well as the resulting proton density, which will be
obtained on a screen behind the plasma according to the proton imaging technique. The parameters of the specific charge distributions
are delivered by a combination of linear regression and nonlinear fitting of the calculated proton density distribution to
the measured optical density of a radiochromic film screen changed by proton exposure. It is shown that superpositions of
spherical Gaussian charge distributions as target plasma are sufficient to simulate various structures in proton imaging measurements,
which makes this method very flexible. 相似文献
20.
L. L. Pappalardo 《The European Physical Journal A - Hadrons and Nuclei》2008,38(2):145-148
Transverse target single-spin asymmetries in semi-inclusive deep inelastic scattering allow to study the so-called Collins
and Sivers mechanisms. The first one connects the poorly known fundamental transversity distribution function, describing
the transverse spin-polarization of quarks in a transversely polarized proton, to the Collins fragmentation function, describing
spin-orbit correlations in the hadron formation process. The second one is sensitive to the Sivers function, which correlates
the intrinsic transverse momentum of quarks with the proton’s spin orientation and is related to the orbital angular momentum
of quarks. Preliminary results on azimuthal single target-spin asymmetries in semi-inclusive electro-production of pions and
kaons at the HERMES experiment are presented. The full data set collected with a transversely polarized hydrogen target was
analyzed providing the HERMES most precise results on the Collins and Sivers azimuthal moments.
Original article based on material presented at HADRON 2007. 相似文献