Compact soft x-ray multichord camera: Design and initial operation

A compact and low cost diagnostic for spatially resolved measurements of soft x-ray or total radiation emission has been designed and realized to be flexibly applied to different plasma physics experiments. Its reduced size (outer diameter=35 mm) makes it suited to a variety of devices. The line integrated emissivity (brightness) has been measured along up to 20 lines of sight, using an array of miniaturized silicon photodiodes. Preliminary prototypes of the diagnostic have been installed in the Madison Symmetric Torus reversed field pinch (RFP) device at University of Wisconsin and in the EXTRAP T2 RFP device at the Royal Institute of Technology in Stockholm. Application of the diagnostic to a gas-fed (argon, helium) magnetoplasma dynamic thruster (MPDT) with an external magnetic field will also be discussed.