Search

Systematic study of the flux pinning at 77 K in $^{235}$U-oxide doped Ag-sheathed Bi2223 tapes irradiated by thermal neutrons has been performed. Within the explored range of $^{235}$U contents ($c\leq 0.75$ at\%) and neutron fluences ($\phi \leq 6\cdot 10^{19}$ m$^{-2}$) pinning capacity increases linearly with fission track density (proportional to $c\phi $). In particular, field $B^{\ast }$ for the maximum volume pinning force ($% F_{p\max }=J_{c}B^{\ast }$) and the irreversiblity field $B_{irr}$ increase linearly with $c\phi $ both for fields parallel and perpendicular to the tape plane. Since $J_{c}$ decreases with $c$ in tapes doped with $^{235}$% U-oxide, $B_{irr}$(77 K, perpendicular field) seems limited to about 4 T. However, more subtle addition of $^{235}$U atoms can produce tapes with flux pinning exceeding that in YBCO type of materials.

We present herein the current status of the X‐ray Absorption Spectroscopy (XAS) Beamline at the 3 GeV Australian Synchrotron. The optical design and performance, details of the insertion device (Wiggler), end station capabilities and construction and commissioning timeline are given.

Gamma-ray spectra from neutron capture by natural silicon have been measured for resonances at 565 and 813 keV. Absolute partial radiative widths are compared with previous results and with valence and shell model calculations.