High current and high power fast kicker system conceptual design and technology overview for DeeMe experiment
A US-Japan collaboration for the high energy physics experiment DeeMe requires a multi G VA high deflection strength fast kicker system. A set of high current, high voltage and high power generators are going to drive a series of kicker magnets to deflect passing beam. Brookhaven researchers have been invited to conduct a conceptual design study for this challenging project. The basic option consists of a set of identical modulators, low impedance transmission lines, and large aperture high inductance kicker magnets. Each modulator shall be capable of driving the kicker magnet with an 8kA to 10kA pulsed current. A desired fast pulse full time of 300 to 400 ns is the most challenging part of the design because of the high inductance magnetic load. The after pulse floor ripple tolerance is 5% or best achievable. Pulse repetition rate is 25Hz continuously.
OPERATION AND CURRENT STATUS OF INJECTION , EXTRACTION , KICKER MAGNET AND THE POWER SUPPLY FOR J-PARC 3 GeV RCS
Stable operation is required for 3-GeV Rapid Cycling Synchrotron (RCS) at High Intensity Proton Accelerator Facility (J-PARC). In the kicker system at extraction section of RCS, there were many troubles for unstable operation of the thyratron switches of the power supply just after 25 pulses per seconds (pps) operation started in February 2009. However, the operation was improved by handling thyratrons in appropriate manner in October 2010. After the Great East Japan Earthquake on March 11, 2011, injection and extraction magnets, power supplies, cables and bus-duct were checked. The results of the measurements and the checks were all not in the problem. We have to accomplish extraction beam power of 1 MW in RCS in the near future. Kicker impedance is the most severe among other impedance sources. We adopt that the matching resistor and newly developed diode are connected at the power supply to reduce the impedance. From the beam test, it is found that induced voltages to the kicker are decreased by the diode and the resistor.
In Vivo Comparison of Synthetic Macroporous Filamentous and Sponge-like Skin Substitute Matrices Reveals Morphometric Features of the Foreign Body Reaction According to 3D Biomaterial Designs
Synthetic macroporous biomaterials are widely used in the field of skin tissue engineering to mimic membrane functions of the native dermis. Biomaterial designs can be subclassified with respect to their shape in fibrous designs, namely fibers, meshes or fleeces, respectively, and porous designs, such as sponges and foams. However, synthetic matrices often have limitations regarding unfavorable foreign body responses (FBRs). Severe FBRs can result in unfavorable disintegration and rejection of an implant, whereas mild FBRs can lead to an acceptable integration of a biomaterial. In this context, comparative in vivo studies of different three-dimensional (3D) matrix designs are rare. Especially, the differences regarding FBRs between synthetically derived filamentous fleeces and sponge-like constructs are unknown. In the present study, the FBRs on two 3D matrix designs were explored after 25 days of subcutaneous implantation in a porcine model. Cellular reactions were quantified histopathologically to investigate in which way the FBR is influenced by the biomaterial architecture. Our results show that FBR metrics (polymorph-nucleated cells and fibrotic reactions) were significantly affected according to the matrix designs. Our findings contribute to a better understanding of the 3D matrix tissue interactions and can be useful for future developments of synthetically derived skin substitute biomaterials.