A Low Cost Table Top X-Pinch Device

Abstract

Summary form only given. This paper reports the conceptualization, designing and construction of a low cost table top X-pinch device. The original target was to develop a 200 kV, 50 kA system with 40-50 ns pulse rise time. In order to keep the cost of the device low, two major changes compared to the conventional X-pinch systems were implemented: (1) develop a low cost transformer based 200 kV pulsed high voltage power source (HVPS) instead of costly Marx generator and (2) develop an integrated pulsed forming line (PFL) with inbuilt water spark gap switch instead of a separate SF6 gas based spark gap. A 1:56 turns transformer, placed inside transformer oil container, was designed to amplify a variable voltage discharge pulse from 7.5 muF (30 kV) capacitor. The dimensions of the PFL were estimated to obtain the system impedance of 4Omega and compressed pulse of 50 ns rise time. To construct the PFL with inbuilt water spark gap switch, the breakdown potential of de-ionized water was systematically investigated. The de-ionized water was found to have the breakdown potential of about 70 kV/mm. For electrical diagnostics, a capacitive voltage probe was made for initial measurements of the HVPS. A V-dot probe and Rogowski groove were constructed and used to monitor the operation of X-pinch. The V-dot probe shows that at 12 kV input voltage to HVPS, the water spark gap (with 3.5 mm gap) of PFL breakdowns at the voltages of about 200 kV Rogowski groove has recorded the current in the range of 15-20 kA, implying the load impedance higher than the intended 4Omega impedance. The time integrated optical imaging confirms the X-pinch formation. The X-ray emissions from the device are investigated using photo-conducting diamond and photodiodes. Investigations to use X-pinch device as a radiography source are undergoing at present