A 600 A High Temperature Superconductor (HTS) current lead has been designed, fabricated and tested. The design of the HTS current lead is optimized to reduce the heat leak and to operate safely ...during fault mode conditions. The current lead consists of a resistive part cooled with helium forced flow and HTS part that is cooled with boiled off helium gas. The HTS part is composed of Bi-2223 with Ag 10 at.% Au alloy matrix. Results of the electrical and thermal tests of the current lead are presented.
In this paper, we describe optical feedback system of VUV Regenerative FEL Amplifier (RAFEL) at the TESLA test facility at DESY. The aim of the RAFEL experiment is to construct fully coherent, ...tunable VUV radiation source by means of applying narrow-band optical feedback in the VUV SASE FEL operating currently at DESY. One of the problem of the realization of the RAFEL is severe requirements for the angular stability of the optical elements (about few microradians). This problem has been solved by means of installation of active alignment system with reference laser. Another problem is alignment of optical elements separated by
65
m
within complicated experimental conditions connected with aperture limitations (down to
6
mm)
. This problem has been solved in two steps. Preliminary alignment with an accuracy of about
80
μrad
has been performed with laser alignment system and OTR screens used at the TTF accelerator for electron beam diagnostics. Final alignment has been performed with VUV SASE FEL radiation. Measured feedback coefficient is about 1 percent and is in agreement with the designed value.
The self-propagating high-temperature synthesis was applied for the production of foam materials under the conditions of microgravity aboard the Mirstation. The materials obtained have a porous ...bimodal structure. The results of space experiments predicted using the interpolation method are checked. An unpredicted phase separation of the combustion products is discovered. The autowave combustion of suspended nickel-clad aluminum solids is observed for the first time. The combustion products were found to have a frame structure.PUBLICATION ABSTRACT
Equilibrium thermal cycles of ac conductors with a current sharing between a superconductor and a substrate are treated. During the propagation process a possibility of the coexistence of the ...superconducting and resistive zones or resistive and normal zones along the conductor is revealed. A possibility of the zone propagation process at the currents above the critical one is stated.
