A magnetic storage ring for neutrons

Neutrons were stored in a torroidal superconducting magnet ring by means of the magnet moment. First measurements of the lifetime of the confined particles in the ring are shown. Neutrons could be traced up to 20 minutes.     

常温核聚变现象实验研究

介绍了1989～1992年在常温核聚变研究方面的主要进展。使用电解法观测到了中子和氚。使用气体放电法观测到了中子和X射线。使用气体升降温度压力循环法观测到了X光胶片感光现象,并初步弄清了感光原因。     

Measurement of the Yield and Angular Distributions of Gamma Rays Originating from the Interaction of 14.1-MeV Neutrons with Chromium Nuclei

Physics of Atomic Nuclei - The reaction induced by the inelastic scattering of 14.1-MeV neutrons on chromium nuclei is studied by means of the tagged-neutron method at the TANGRA (TAgged Neutrons...     

Generation of Deuterium Ions in a Vacuum Arc with Composite Gas-Saturated Cathode and in a Low-pressure Arc

Russian Physics Journal - Plasma containing deuterium ions is used, for example, to generate neutron flows. Neutrons are generated in nuclear reactions of interaction of accelerated ion beams...     

Channeling of Neutrons in a Nonmagnetic Planar Waveguide

Journal of Experimental and Theoretical Physics - The propagation of neutrons in the middle layer of a planar waveguide, which is a three-layer thin film, has been studied. Neutrons emitted from...     

The photoneutron cross section of 6Li

The photoneutron cross section of ⁶Li has been measured from threshold to 17 MeV using bremsstrahlung from an electron synchrotron. Neutrons were detected by a high-efficiency multi-BF3-counter detection system. The cross section shows broad peaks at 12 MeV and 16 MeV with no other structure apparent.     

Status and plans for neutral weak form factors measurements

We report on a mature experimental program to measure the parity-violating asymmetry in the elastic scattering of longitudinally polarized electrons from unpolarized ¹H, ²H and ⁴He targets. The focus is the measurement of the nucleon neutral weak form factors at intermediate four-momentum transfer (0.1 < Q ² < 1) (GeV/c)² which provide information about the impact of virtual strange quarks on the charge and current distributions inside nucleons. We report on recent technical progress in the design and scope of the experimental techniques. The physics implications of the published measurements are discussed and the current status and anticipated results from experiments under construction are summarized.Received: 30 September 2002, Published online: 22 October 2003PACS: 12.15.Mm Neutral Currents - 14.20.Dh Protons and Neutrons     

The photoneutron production cross section in Be

The photoneutron production cross section in ⁹Be was measured with a synchrotron using energy sweeping. Neutrons were detected with a multi-BF₃-counter flat-response detection system. Under high resolution the cross section shows 23 maxima between 6 and 27 MeV which are caused predominantly by E1 transitions.     

The interaction of Ultra-Cold Neutrons (UCN) with liquid helium and a superthermal UCN source

We discuss the interaction of Ultra-Cold and Cold Neutrons with superfluid ⁴He and show that this interaction has all the characteristics which are necessary for the achievement of extremely high densities of UCN.     

Measurement of the ultra cold neutron production rate in an external liquid helium source

Ultra Cold Neutrons have been produced by down scattering of cold neutrons $\text{(λ = 10}\text{A}\text{?}\text{)}$ on liquid helium. The measured production rate is in agreement with the calculated value.     

The photoneutron cross section in 13C

The photoneutron cross section in ¹³C was measured using bremsstrahlung from an electron synchrotron operated in energy sweeping mode. Neutrons were detected by a multi-BF₃-counter detection system. Decorrelated cross-section ordinates were calculated directly using a modified Leiss-Penfold analysis. The cross section from threshold to 25 MeV shows detailed structure, some nine maxima, in agreement with recent continuum shell-model calculations.     

Operation of a superthermal ultra-cold neutron source and the storage of ultra-cold neutrons in superfluid Helium4

We report the first successful operation of a superthermal UCN source and the observation of the storage of Ultra-Cold Neutrons in superfluid Helium⁴ at Temperatures in the range 0.5–1.15K. From the observations we obtain the total cross section for UCN scattering by superfluid Helium. The temperature dependence of the total cross section is found to be consistent with calculations which include the effects of phonon absorption and phonon and roton scattering.     

Neutron-multiplicity in deep inelastic collisions: 365 MeV Cu+Au system

Neutrons have been detected in coincidence with the two outgoing fragments in deep inelastic reactions of⁶³Cu on¹⁹⁷Au at 365 MeV. Most of these neutrons are evapored from the fully accelerated fragments. An additionnal low energy contribution appears.     

Evidence for the ground-state resonance of 26O

Evidence for the ground state of the neutron-unbound nucleus (26)O was observed for the first time in the single proton-knockout reaction from a 82 MeV/u (27)F beam. Neutrons were measured in coincidence with (24)O fragments. (26)O was determined to be unbound by 150(-150)(+50) keV from the observation of low-energy neutrons. This result agrees with recent shell-model calculations based on microscopic two- and three-nucleon forces.     

Channeling of Neutrons in the Potential Well of a Planar Waveguide

The channeling of neutrons in a three-layer planar waveguide with a neutron-optical potential well is studied. Neutrons incident on a sample surface, which propagate in a middle layer and escape from the waveguide end in the form of a narrow divergent beam, are detected. The decay parameter of a neutron wave inside the waveguide is measured as a function of the potential well depth. Experimental results are compared with a theory.     

Neutron and light-charged-particle productions in proton-induced reactions on 208Pb at 62.9 MeV

Neutrons and light charged particles produced in 62.9MeV proton-induced reactions on ²⁰⁸Pb were measured during a single experiment performed at the CYCLONE facility in Louvain-la-Neuve (Belgium). Two independent experimental set-ups were used to extract double differential cross-sections for neutrons, protons, deuterons, tritons, ³He and alpha-particles. Charged particles were detected using a set of Si- Si- CsI telescopes from 25^° to 155^°, by step of 10 degrees. Neutrons were measured using shielded DeMoN counters, liquid NE213 scintillators, at 24^°, 35^°, 55^°, 80^° and 120^°. These data allowed the determination of angle differential, energy differential and total production cross-sections. A comparison with theoretical calculations (MCNPX, FLUKA and TALYS) has been performed. It shows that the neutron and proton production rates are well predicted by MCNPX, using the INCL4 option. All the other codes underestimate the neutron production whereas they overestimate the proton one. For composite particles, which represent 17% of the charged particle total reaction cross-section, neither the shape nor the amplitude of the cross-sections are correctly predicted by the models.     

Photofission for the production of radioactive beams: Experimental data from an on-line measurement

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     

Deuterium Clusters Fusion Induced by the Intense Femtosecond Laser Pulse

Neutrons （2.45MeV） from deuterium cluster fusion induced by the intense femtosecond （3Ors） laser pulse are experimentally demonstrated. The average neutron yield 103 per shot is obtained. It is found that the yield slightly increases with the increasing laser spot size. No neutron can be observed when the laser intensity I 〈 4.3 × 10^15 W/cm^2.     

Über die Wirkungsquerschnitte einigern,n α-Reaktionen für Neutronenenergien zwischen 12 und 19 MeV

Cross sections of somen, nα-reactions have been investigated in the energy range of the neutrons from 12 to 19.6 MeV by measuring the radioactivities produced. Neutrons of these energies were produced by bombarding a thin tritium-target with 3 MeV-Deuterons. In all cases considered the cross section increases rapidly with the neutron energy. In addition somen, 2n-reactions were studied in the same way; the results were compared with cross sections which were calculated according to the statistical theory.