Linear transformer driver: Difference between revisions

Revision as of 18:49, 26 August 2012

Revision as of 16:28, 29 August 2012

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{{Context|date=April 2010}}

The '''linear transformer driver''' (LTD) is a low-voltage variant of the [[inductive- voltage- adder]] (IVA) technology first applied at [[Arzamas-16]] (now [[Sarov]]), Russia and later at the Institute for high-current electronics ([[IHCE]]) in [[Tomsk]], Russia. The [[Hermes III]] gamma-ray simulator at [[Sandia National Laboratories]] is another example of an IVA design. In IVA designs, each megavolt “stage” is added in series to the proceeding stage using large iron cores to inductively isolate the individual stages. This concept permits a very large voltage to be generated by adding the voltage from each stage in series. Hermes III delivers a peak voltage of 20 MV to an [[electron beam]] loaded to the device.

LTDs use the same IVA concept but use low voltage components. Each individual cavity (similar to an IVA stage) operates at an [[open circuit]] voltage typically in the range of 100 kV to 200 kV. There is no high-voltage switching or pulse forming! An LTD cavity is composed of a number of "bricks" connected in parallel. The choice of the brick [[capacitance]], [[resistance]], and [[inductance]] defines the base pulse shape of the brick, and therefore the pulse shape and current of the cavity and, finally, the module. There are no further pulse-forming components. The efficiency of energy coupling from the [[storage capacitorscapacitor]]s to the load is very high, typically over 60–70%.

Pulse width and pulse shape are simple design choices for LTD generators. By tailoring the capacitors and switches one can generate a wide range of electrical pulse shapes.

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Additionally, LTDs provide a range of flexible accelerator designs. Adding bricks in parallel per cavity increases the current per cavity. Adding cavities in series increases the voltage per module. Adding modules in parallel gives the final accelerator current. LTDs have been built with pulse widths as short as ~ 50 ns and as long as ~ 1 µs. LTD generators have achieved voltages greater than 700 kV. LTD drivers have reached currents greater than 1 MA. New LTD drivers are under construction at many laboratories and the performance figures quoted above are subject to change.

Fundamentally, LTDs provide a new flexible & compact pulsed-power architecture. LTDs are particularly suited for high-power low-energy applications such as [[radiography]] sources, [[x-ray simulatorssimulator]]s, and [[gamma-ray simulatorssimulator]]s.