Study of Muon-Catalyzed Fusion in Ortho–Para Controlled Solid Deuterium

Recently, the applicability of Penning trap mass spectrometry has been extended to nuclides with a half-life of less than one second. The mass of ³³Ar (T _1/2=174 ms) was measured using the ISOLTRAP spectrometer with an accuracy of 4.2 keV. This measurement provided a stringent test of the Isobaric Multiplet Mass Equation (IMME) at mass number A=33 and isospin T=3/2. The fast measurement cycle that shows the way to other measurements of very-short-lived nuclides is presented. Furthermore, the results of the IMME test are displayed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Review of Muon Catalyzed Fusion Experiments – Activities after EXAT98 and Future Perspectives

Since EXAT98 at Ascona, significant progress has been marked for experimental investigations of the fundamental understanding of muon catalyzed fusion (μCF) phenomena in D–T, D₂ and other hydrogen systems. Future progress in the μCF studies is now guaranteed due to the successful launching of advanced accelerator projects such as JAERI-KEK Joint Proton Accelerator project and RI Beam Factory project at RIKEN. Also, the start of the next-phase thermal nuclear fusion project of ITER becomes promising so that some future contributions from ITER to μCF or vice-versa can be expected for various physical or technological aspects of fusion research. The future progress of μCF studies will also be promoted because of the growth of various other scientific research using muons. The essence of all these subjects is reviewed. This revised version was published online in August 2006 with corrections to the Cover Date.     

The Muon Science Facility at the JKJ Project

The muon science facility is one of the experimental arenas of the JKJ project, which was recently approved for construction in a period from 2001 to 2006, as well as neutron science, particle and nuclear physics, neutrino physics and nuclear transmutation science. The muon science experimental area is planned to be located in the integrated building of the facility for the materials and life science study. One muon target will be installed upstream of the neutron target in a period of phase 1. The beam line and facility are designed to allow the later installation of a 2nd muon target in a more upstream location. The detailed design for electricity, cooling water, primary proton beam line, one muon target and secondary beam lines (a superconducting solenoid decay muon channel, a dedicated surface muon channel, and an ultra slow muon channel) is underway. In the symposium, a latest status of the muon science facility at JKJ project will be reported. This revised version was published online in August 2006 with corrections to the Cover Date.     

Diffusion of positive mouns in copper detected by zero-field μSR

Using the Zero-Field μSR method coupled with the unique pulsed muon beam, new systematic measurements of diffusion (hopping) rate of positive muon were performed for the two ultra-pure copper samples (residual resistivity ratio = 18,000 and 7,350) and for the copper doped with 95 ppm iron. For these measurements a new detection system with an improved time resolution was installed to reduce the distortion of μ-e decay time spectrum due to the counting loss of positrons. A preliminary result suggests that the leveling-off of the hopping rate below 0.5 K is not affected by the purity for the ultra-pure sample, while it is strongly modified for the doped copper.     

A Study of Electronic Equalization Scheme Enabling Optically Pre-Filtered 1 bit/s/Hz DWDM Transmission

A numerical simulation shows that by using electronic equalizers 1 bit/s/Hz spectral efficiency can be attained with the same signal quality as a 0.8 bit/s/Hz system. Waveform distortion due to optical band-limiting is corrected with nearly 3 dB improvement of the Q-penalty.     

Probing oxygen in high Tc superconductor LaSrCuO by negative muons

A novel microscopic method of muon spin rotation for negative muon (μ⁻) attached to oxygen is applied on highT _c materials LaSrCuO. The paramagnetic shift and relaxation rate are measured as a function of Sr concentration and temperature. Analysis shows the large difference in shift and relaxation between two different sites. A large anisotropy was also observed by preliminary measurements along different crystalline axes.     

μ− SR studies of oxide-superconductorsSR studies of oxide-superconductors

The negative muon spin rotation method (μ⁻ SR) has been applied to studies of electronic states at oxygen sites of oxide superconductors YBa₂Cu₃O₇, Nd_2−x Ce _x CuO_4−δ (x=0.15, oxygen reduced), LiTi₂O₄ and related oxide-insulators La₂CuO_4−δ, CuO, Cu₂O. The paramagnetic shifts of μ⁻ trapped at oxygen nuclei in these polycrystalline powder samples have been measured at 300 K. All the measured shifts are positive. In copper-oxides the paramagnetic shifts are of the order 10⁻³, while in LiTi₂O₄ is very small (8.4±3.34×10⁻⁵). In YBa₂Cu₃O₇, a fast μ⁻ spin relaxation timeT ₂ ^* (∼ 200 ns) has been observed; the reason for this is unknown and further studies are now in progress.     

Surface muon production in medium energy heavy ion reaction at RIKEN

A new type of beam transport system for secondary light charged particles (“Large Ω” Beam Course) has been constructed and used to transport surface muons from the decay of pions produced in heavy-ion reactions at RIKEN Ring Cyclotron (RRC). In an experiment carried out using a¹⁴N beam of 135 MeV/u and a carbon target of 0.9 g/cm² thickness, the surface muon intensity obtained in 5×5 cm² sample was around 100 1/s for 500 nA of the primary beam. This number may be increased by two orders if the energy were doubled.     

μSR and Mössbauer studies on semiconducting YBa2(Cu0.95Fe0.05)3O6+δ

μSR and⁵⁷Fe Mössbauer spectroscopy were used to study the magnetic properties of powders ofsemiconducting YBa, (Cu_0.95Fe_0.05)₃O_6+δ using the same sample in the temperature range from 4–300 K. TF and ZF μSR were performed at the BOOM facility at KEK using the pulsed surface beam.     

Numerical, analytical, and experimental studies of scattering from very rough surfaces and backscattering enhancement

This paper Presents numerical simulations, theoretical analysis, and millimeter wave experiments for scattering from one-dimensional very rough surfaces. First, numerical simulations are used to investigate the effects of roughness spectrum, height variation, interface medium, polarization, and incident angle on the backscattering enhancement. The enhanced backscattering due to rough surface scattering is divided into two cases; the RMS height close to a wavelength and RMS slope close to unity, and RMS height much smaller than a wavelength with surface wave contributions. Results also show that the enhancement is sensitive to the roughness spectrum. Next, a theory based on the first- and second-order Kirchhoff approximation modified with angular and propagation shadowing is developed. The theoretical solutions provide a physical explanation of backscattering enhancement and agree well with the numerical results. In addition to the scattering of a monochromatic wave, the analytical results of the broadening and lateral spreading of a pulsed beam wave scattering from rough surfaces are also discussed. Finally, the existence of backscattering enhancement from one-dimensional very rough conducting surfaces with exact Gaussian statistics and Gaussian roughness spectrum is verified by a millimeter-wave experiment. Experimental results which show enhanced backscattering for both TE and TM polarizations for different angles of incidence are presented.