Development of Compact Plasma Radiation Source (CPRS) at IAC for imaging

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Introduction

• N.Ratakhin et al. "Compact pulse power generator for X-pinch researches" 28th ICPIG, July 15-20, 2007, Prague, Czech Republi [1]

"The main requirements imposed on the generator are the current amplitude 150-300 kA and the rate of the current rise 1-2 kA/ns. At the moment, these parameters of the current pulse can be provided only by enough large fixed-site generators weighing from 300 kg to several tons. These shortcomings limit to a great extent the feasibility of this diagnostic technique in studies of extreme states. Therefore, the design of a portable pulse generator which provides the required parameters makes it possible to proceed to a new level of diagnostics of fast processes."

Comparison of X-Pinch X-ray Radiography Facilities with other X-Ray sources

X-Pinch :

• few micron source size -> study small-scale objects
• 0.1 - 10 ns Pulse Width -> study short living objects
• X-Pinch Facilities used Pulsed Power and could be made small and compact

Synchrotron Radiation:

Laser Compton Scattering:

Design's Possibilities

PRS based on transformation of ISIS Induction Cell Driver

File:ISIS Modification for X-pinch 012813.pdf

PRS based on building separate Marx Generator or (Marx Generator + Pulse Forming Line)

File:ISIS Marx 020413.pdf

PRS based on Linear Transformer Driver (LTD) technologies

• A. A. Kim Development and tests of fast 1-MA linear transformer driver stages Phys. Rev. ST Accel. Beams 12, 050402 (2009)

"The LTD driver is an induction generator similar to the induction accelerator (LIA) [1,2], the inductive voltage adder (IVA) [3–6], and the linear pulsed transformer (LPT)"

Each LTD stage (or sometimes called LTD cavities) consists of three different elements: a capacitor, a gas spark switch and a ferromagnetic core. The necessity of ferromagnetic core is to inductively connect stage to TL. So the one stage can be used as building block to design the bigger facilities. Buy designing the different stages and connecting them in different way a great variety id devices can be constructed.

1. M.G.Mazarakis A compact, high-voltage e-beam pulser 1999 IEEE [2]
2. M.G.Mazarakis Ultrafast LTD's for bremsstrahlung diodes and Z-pinches 2002 IEEE [3]
3. A.A.Kim 1 MV ULTRA-FAST LTD GENERATOR 2003 IEEE [4]
4. M.G.Mazarakis HIGH CURRENT FAST 100-NS LTD DRIVER DEVELOPMENT IN SANDIA LABORATORY 2005 IEEE [5]
5. M.G.Mazarakis Conceptual Design for a Linear-Transformer Driver (LTD)-Based Refurbishment and Upgrade of the Saturn Accelerator Pulse-Power System SANDIA REPORT SAND2006-5811, 2006 [6]
6. M.G. Mazarakis Linear Transformer Driver (LTD) development at Sandia national laboratory 2009 IEEE [7]
7. J.R.Woodworth Low-inductance gas switches for linear transformer drivers Phys. Rev. ST Accel. Beams 12, 060401 (2009) [8]
8. W.A.Stygar Shaping the output pulse of a linear-transformer-driver module Phys. Rev. ST Accel. Beams 12, 030402 (2009) [9]
9. A.A. Kim Development and tests of fast 1-MA linear transformer driver stages Phys. Rev. ST Accel. Beams 12, 050402 (2009) [10]
10. M.G. Mazarakis High current, 0.5-MA, fast, 100-ns, linear transformer driver experiments Phys. Rev. ST Accel. Beams 12, 050401 (2009) [11]
11. M.G. Mazarakis High-Current Linear Transformer Driver Development at Sandia National Laboratories 2010 IEEE [12]
12. J. R. Woodworth Compact 810 kA linear transformer driver cavity Phys. Rev. ST Accel. Beams 14, 040401 (2011) [13]

LRC circuit with Low inductance capacitors and Low Inductance Switches

For radiographic application we need the pulser with 150-300 kA current and 1-2 kA/ns rise time. Because of that, one LTD stage is enough to build the entirely facility. Because we do not need inductively stuck many stages together the necessity of massive ferromagnetic core is relaxed.

The whole stage can be easily analysed as LRC circuit with LTspice code. The precise design of cavity and transmission line should be done with 3D time domain EM code XFtdt.

Design of ISIS Compact Plasma Radiation Source (CPRS)

Requirements:

1. Compact and Light
2. 150-300 kA
3. 1-2 kA/ns rise time

• m - Number of capacitors
• Vo - Capacitir charging voltage
• Ipeak - Load peak current
• Vpeak - Load peak voltage
• tpeak - Time of peak

• m = 8 -> Ipeak = 200 kA, Vpeak = 50 kV (Vo = 91 kV), tpeak = 97ns, 2.1 kA/ns
• m = 12 -> Ipeak = 250 kA, Vpeak = 50 kV (Vo = 91 kV), tpeak = 116ns, 2.2 kA/ns
• m = 16 -> Ipeak = 250 kA, Vpeak = 50 kV (Vo = 91 kV), tpeak = 155ns, 1.6 kA/ns
• m = 16 -> Ipeak = 200 kA, Vpeak = 40 kV (Vo = 73 kV), tpeak = 155ns, 1.3 kA/ns
• m = 20 -> Ipeak = 300 kA, Vpeak = 55 kV (Vo = 100 kV), tpeak = 175ns, 1.7 kA/ns