共查询到20条相似文献,搜索用时 15 毫秒
1.
M. Kitaguchi M. Hino Y. Kawabata S. Tasaki H. Hayashida R. Maruyama T. Ebisawa 《Physica B: Condensed Matter》2009,404(17):2590-2593
A new type of neutron resonance spin flipper (RSF) with high frequency oscillating magnetic field has been developed for Modulated IntEnsity by Zero Effort (MIEZE) spectrometer at cold neutron beam line MINE1 at JRR-3M reactor in JAEA. Dipole magnets enable us to provide the strong static fields for the RSFs. MIEZE signals have been demonstrated with the effective frequency of 600 kHz by using the new RSFs. The contrast of the signals was 0.58. The MIEZE spectrometer is under final process to practical use. The spectrometers can also be applied to the pulsed neutrons like J-PARC. 相似文献
2.
M. Daum P. FierlingerB. Franke P. GeltenbortL. Goeltl E. GutsmiedlJ. Karch G. KesslerK. Kirch H.-C. KochA. Kraft T. LauerB. Lauss E. PierreG. Pignol D. ReggianiP. Schmidt-Wellenburg Yu. SobolevT. Zechlau G. Zsigmond 《Physics letters. [Part B]》2011,704(5):456-460
Ultracold neutrons were stored in a volume, using a magnetic dipole field shutter. Radial confinement was provided by material walls. Low-field seeking neutrons were axially confined above the magnetic field. High-field seeking neutrons are trapped inside the magnetic field. They can systematically shift the measured neutron lifetime to lower values in experiments with magnetic confinement. 相似文献
3.
R. Majumdar 《Zeitschrift für Physik A Hadrons and Nuclei》1990,336(3):259-262
The distribution of the discrete 1h 9/2, 2f 7/2, 1i 13/2 and 2f 5/2 proton states of209Bi and 2g 9/2, 1i 11/2, 1j 15/2 and 2g7/2 neutron states of209Pb have been obtained within the particle-vibration coupling model calculation and compared with the experimental datas baising on the most recent high resolution stripping reaction on208Pb using 480 MeV12C projectile. The optimised shell model energies arising from the core-polarisation effect have profound influence for both the study of the structures of the high spin continuum shell model states of208Pb and stability of superheavy nuclei. 相似文献
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5.
Charge neutrality, a spin 1/2 and an associated magnetic moment of the neutron make it an ideal probe of quantal spinor evolutions.
Polarized neutron interferometry in magnetic field Hamiltonians has thus scored several firsts such as direct verification
of Pauli anticommutation, experimental separation of geometric and dynamical phases and observation of non-cyclic amplitudes
and phases. This paper provides a flavour of the physics learnt from such experiments. 相似文献
6.
C. G. Lindén I. Bergström J. Blomqvist K. -G. Rensfelt H. Sergolle K. Westerberg 《Zeitschrift für Physik A Hadrons and Nuclei》1976,277(3):273-290
Using the204Hg(α, 3n) reaction withα-particles of about 40 MeV, we have proved by applying nowadays conventionalγ-ray spectroscopy in-beam technique, that there are two isomeric states in205Pb at the excitation energies 5,161.3 and 3,195.5 keV having the half-lives 71±3 and 217±5 ns, respectively. These isomeric states have spins and parities 33/2+ and 25/2? and are mainly due to thei 13 2/?3 andi 13 2/?2 p 1 2/?1 configurations, respectively. This conclusion is supported by the experimentalg-factors of these states being ?0.159±0.008 and ?0.0676±0.0011, respectively. It is furthermore shown that theE2 effective neutron charge is the same forE2 transitions from the 33/2+ state in205Pb and from the 12+ state in206Pb as required by the assumption that the208Pb core is responsible for the totalE2 strength of the neutron holes, and that these states are due to thei 13 2/?3 andi 13 2/?2 configurations. The calculatedB(E3) values ofE3 transitions from isomeric states in205Pb and206Pb agree reasonably well with the experimental values as expected from the assumption that theE3-strength should come from particle coupling to the octupole states of the208Pb core. The energies of the six most well established excited states in205Pb with angular momenta in the region 19/2–33/2 were calculated using empirical single-particle energies, empirical two-particle interactions and angular momentum algebra. The average deviation between experimental and calculated energies is ?3 keV and the root mean square deviation 6 keV as compared to the uncertainty ± 5 keV in the nuclear masses used in the calculation. For the orbits concerned the shell model is thus valid with an extremely high precision. The contribution of effective three-particle interaction in these orbits must consequently be less than about 5 keV. 相似文献
7.
Koichi Mayumi Michihiro Nagao Hitoshi Endo Noboru Osaka Mitsuhiro Shibayama Kohzo Ito 《Physica B: Condensed Matter》2009,404(17):2600-2602
The dynamics of a molecular necklace known as polyrotaxane (PR), in which α-cyclodextrins (CDs) are threaded into a poly (ethylene glycol) (PEG) chain, was investigated by means of neutron spin echo (NSE) measurements. We observed that threading CDs into PEG slowed down the local dynamics and changed its Q-dependence. A solution of PEG in DMSO-d6 showed a dynamical crossover from collective diffusion dynamics to the Zimm mode, just as in conventional polymer solutions; however, the motion of PR in DMSO-d6 was diffusive for the whole Q range. This may be because the persistence length lp of PR was much larger than that of PEG and was similar to the mesh size of PR. The diffusive mode in a high Q regime, corresponding to a length scale of less than the lp value of PR, contained the mode of the sliding of CDs along a rod-like PEG segment in one dimension. 相似文献
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Ramen Majumdar 《Zeitschrift für Physik A Hadrons and Nuclei》1995,351(4):405-409
The neutron strength functions of the high-spin 1g
7/2 and 1h
11/2 hole states of the207Pb have been deduced within the formalism of the hole-core vibrational coupling scheme. The attenuation of the shell-model strengths of these two high-spin hole states have been compared with the distribution of the neutron strength functions of the discrete 1h
9/2 and 1i
13/2 states. The theoretical results have been discussed in the light of the recent experimental findings on the neutron hole orbitals of the207Pb nucleus. Side by the side the implication of the present research works has been reviewed on the basis of the other existing theoretical calculations on the high-spin neutron hole states of the207Pb. 相似文献
10.
The fragmentations of the 3s 1/2, 2d 3/2, 2d 5/2 and 1.h 11/2 proton states were deduced using the hole-core coupling model calculation and compared with recent206Pb ( \(\vec d\) ,3He) reaction data. The energies of the proton fragments carrying the main shell-model strengths were used to deduce the radial wave functions of205T1 and207Tl that give rise to charge distributions of these nuclei. From their respective charge distributions, root mean square radii of206Pb and208Pb were extracted. 相似文献
11.
H. Kira Y. Sakaguchi T. Oku J. Suzuki M. Nakamura M. Arai K. Kakurai Y. Endo Y. Arimoto T. Ino H.M. Shimizu T. Kamiyama K. Tsutsumi K. Ohoyama H. Hiraka K. Yamada L.-J. Chang 《Physica B: Condensed Matter》2011,406(12):2433-2435
We have begun the development of an in-situ spin-exchange optical pumping (SEOP) system aiming to use it as a neutron spin filter for incident beam polarization at the Japan Proton Accelerator Research Complex (J-PARC). To use it, it is recommended that the optics be adjusted easily, have high stability, and have a small size. In this paper we improved our previous SEOP system aiming to use it in J-PARC and performed a neutron beam test at the JRR-3 NOP beamline to see the performance of the neutron spin filter (NSF). The polarization of the 3He gas reached 73%. This paper gives the present status of the development of in-situ SEOP system in J-PARC. 相似文献
12.
Polarized neutron instruments will occupy about 80% of the Jülich Centre for Neutron Science (JCNS) instrument park. A successful polarized 3He program will be integral to many of these instruments. We have been focusing the developments on spin-exchange optical pumping (SEOP) to polarize the 3He gas in situ. Where possible, in situ polarization using the SEOP method will provide higher time averaged performance of the instruments. Further this allows a custom-built and independent source of polarized 3He to be developed optimized for each instruments demands. In this paper we will: present an argument for the advantages of in situ polarization; describe an in situ polarizer we have constructed, and initial tests of its performance; describe testing of polarization analysis for small angle neutron scattering on biological samples, and our plans for an in situ polarizer for this application. 相似文献
13.
This paper describes the dynamics of a water-in-oil microemulsion from the dilute to the dense droplet region. Using the relative intermediate form factor method for neutron spin echo data analyses [M. Nagao, H. Seto, Phys. Rev. E 78 (2008) 011507], the shape and structure fluctuations of a droplet microemulsion are successfully decoupled. In the previous paper, we used the first cumulant analysis of the shape fluctuation model, while the full fitting form of the same model is applied in this paper. The final results of the fittings using the first cumulant approximation and the full form of the model are almost identical, and therefore, the validity of the method is strengthened. The estimated bending modulus of the surfactant membrane, κ, is basically the same, within the experimental errors, in the previous and present results. The κ is not affected much by an increase of the droplet concentration. A clear dynamic slowing down of the water droplets is highlighted at the length scale corresponding to the inter-droplet distance from the structure fluctuation analysis. 相似文献
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Takashi Ino Mitsutaka Nakamura Takayuki Oku Takenao Shinohara Jun-ichi Suzuki Kenji Ohoyama Haruhiro Hiraka 《Physica B: Condensed Matter》2009,404(17):2667-2669
We have designed and demonstrated a prototype on-beam spin-exchange optical pumping (SEOP) 3He neutron spin filter (NSF). It is designed as the incident neutron polarizer for spallation neutron sources, where the installation space is limited due to thick radiation shielding. The size of the NSF is roughly 50 cm×50 cm×25 cm including the diode-laser optics with a frequency narrowing external cavity, and a cylindrical 3He cell as large as a diameter of 5 cm and a length of 10 cm can fit. A neutron beam test was performed at the NOP beamline of JRR-3 to see the performance of the NSF. 相似文献
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Joachim E. Trümper 《Progress in Particle and Nuclear Physics》2011,66(3):674-680
We summarize the constraints on the equation of state of high-density nuclear matter derived from neutron star observations. The most stringent constraints are provided by the largest mass, the largest radius, the highest rotational frequency, and the maximum surface gravity observed for neutron stars. The combination of these constraints allows only nuclear equations of state which are quite stiff. 相似文献
18.
In this work we are particularly interested for GaAs/Ga1−xAlxAs V-groove quantum wires. The paper presents an efficient and simple method for energy spectra and wave function calculations of electrons and holes in V-groove quantum wires. The method is based on the coordinate transformation of the V-groove quantum wire structure and the computational domain using a function proposed by Inoshita. Then, the Hamiltonian followed by implementation of the FDM (Finite Difference Method) in the new computational space leads to an eigenvalues problem resolved using specialized LAPACK’s routines. The influence of the parameters introduced in the mathematical function, is studied on the energy levels of electrons and holes as well as the oscillator strengths. 相似文献
19.
The PEARL instrument at ISIS has been designed for, and dedicated to, in situ studies of materials at high pressure, using the Paris–Edinburgh press. In recent years, upgrades to the instrument have led to improvements in data quality and the range of achievable pressures and temperatures; currently 0.5–28?GPa and 80–1400?K. This paper describes the technical characteristics of the instrument, its current capabilities, and gives a brief overview of the science that has been performed, using representative examples. 相似文献
20.
To theoretically explore the feasibility of neutron dose characterized by Cerenkov photons, the relationship between Cerenkov photons and neutron dose in a water phantom was quantified using the Monte Carlo toolkit Geant4. Results showed that the ratio of the neutron dose deposited by secondary electrons above Cerenkov threshold energy to the total neutron dose is approximately a constant for monoenergetic neutrons from 0.01 eV to 100 eV. With the initial neutron beam energy from 0.01 eV to 100 eV, the number of Cerenkov photons has a good correlation with the total neutron dose along the central axis of the water phantom. The changes of neutron energy spectrum and mechanism analysis also explored at different depths. And the ratio of total neutron dose to the intensity of Cerenkov photons is independent of neutron energy for neutrons from 0.01 eV to 100 eV. These findings indicate that Cerenkov radiation also has potential in the application of neutron dose measurement in some specific fields. 相似文献