Superconducting bending magnets for compact synchrotron radiation source
A 180 degrees superconducting magnet has been constructed for a synchrotron radiation source. The authors describe the superconducting magnet design and some component test results for the compact synchrotron radiation source. The magnetic field at the electron orbit is 4.5 T. The bending radius is 0.593 m. The magnet has several features such as low liquid helium consumption ratio, persistent current operation, high homogeneous magnetic fields, and leakage flux shielding by the iron core surrounding the cryostat. Component tests of persistent current switches of 15 Omega and 3 Omega and a superconducting joint test have been performed.<<ETX>>
Design of a compact storage ring for industrial research
An 800‐MeV compact storage ring is under construction for development of the technology of a compact ring and for research of x‐ray lithography and material analysis. Synchrotron radiation with a critical wavelength of 0.65 nm is emitted from a pair of superconducting bending magnets. A straight section of the ring has only one quadrupole magnet to make the smaller ring. An injection efficiency with a single kicker magnet is optimized by computer simulation. The kicker field strength and an injection angle are determined. A beam tracking with a numerical integration method shows this ring has a sufficiently wide dynamic aperture of ‖x‖≂30 mm and ‖y‖≂50 mm at the center of the bending magnet, which has βxmin and βymax. A 1‐GeV synchrotron is used as an injector, which has accelerated a beam up to 1 GeV.
Mass Loss History of Evolved Stars
We provide high-resolution maps of the circumstellar dust shells of several dozen Asymptotic Giant Branch (AGB) stars using data from the Spitzer space telescope Multiband Imaging Photometer (MIPS) imaged at 70μm. AGB stars are the major contributors of chemical elements such as carbon, oxygen and silicon, which are essential to the existence of life in the universe, through mass loss processes that take place at the surface of the star. We probe the spatial distribution of cold (∼40 K) dust grains in order to trace the history of mass loss from the observed radial density variation in these shells. Our images illustrate that different morphologies may evolve because AGB stars can already interact with the interstellar medium (ISM) that surrounds them even at these early stages of the AGB mass loss history. Relative motion of the star as well as the ISM with respect to the local environment may be of particular importance for shell structure evolution.