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

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To do list (for design of IAC compact PRS)

• Look at switches. Right now I have used Lsw = 10 nH (Mazarakis 1999 [1]). But if the switch inductance, say, is Lsw = 115 nH we will need at least 10 - 20 bricks (depending on kA/ns needed). If so, we do have anymore the compact PRS (4 capacitors). Now we are indeed coming toward to LTD cavity design..

• X = F(Ip, Tp, wire) Look at dependence of X-Ray parameters, such as time, width, power. energy etc., on the current parameters, such as peak current, time to peak and on the wire parameters, such, material, diameter, length. It could happens that for compact PRS, when current width is small, we will not have enough time to make X-Ray Pulse. Also, for imaging with good time resolution (for. Khalid), we want the smallest X-Ray pulse width (<1ns) without jitter and with good reproducibility.

• Check, if it's true, that for smaller Ipeak, tpeak, the X-ray pulse is bigger (tens of ns). If so, compact PRS will be challenge, because we will not have enough time resolution for imaging

• Look at voltage breakdown
  • air: 3 kV/mm
  • vacuum:

• Design idea
  • make open easy access design
  • use "critically damped" design to eliminate negative wave

• Look at diagnostics

• Look at compact X-Pinch design

X-Ray pulse dependence on wire peak current, rise time and total energy deposition

• dI/dt > 1 kA/ns [2]

Introduction

• N.Ratakhin et al. "Compact pulse power generator for X-pinch researches" 28th ICPIG, July 15-20, 2007, Prague, Czech Republi [3]

• "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."

• Innovation idea for compact PRS: To have good time resolution (< 1 ns) we basically need the big X-Pinch facilities. There are no many of them around the world. There are the big needs for smallest X-Pinch machines. They usually have big (10-100ns) time resolution (check if this is true and why). Design IAC compact PRS which will have small compact size and still will have a good time resolution. (if we can)

• 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.

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:

PRS based on Linear Transformer Driver (LTD) technologies

"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)" [4]

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. [5]

What was done with LTD:

• A compact, high-voltage e-beam pulser: 3 MV, 100 kA
• A compact, high-voltage e-beam pulser: 10 MV, 100 kA
• 1 MV ultra-fast LTD generator: 1 MV, 125 kA
• High Current Fast 100-NS cavity: 100 kV, 1 MA
• LTD-II: 100 kV, 490 kA
• LTD-III: 92 kV, 810 kA
• etc...

Pulsed Power Company

• General Atomics Electronic Systems, Inc. (GA-ESI), San-Diego [6]
• General Atomics Electronic Systems, Inc.: Series PDS/PDSS - Fast Pulse Capacitors [7]
• Pulsed Power Laboratories. Inc [8]
• L-3 Applied Technologies - Pulse Sciences [9]
• L-3 Applied Technologies - Pulse Sciences: HV Switches [10]

Literature

Literature: LTD tehnologies

1. M.G.Mazarakis, A compact, high-voltage e-beam pulser, 1999 IEEE [11]
2. M.G.Mazarakis Ultrafast LTD's for bremsstrahlung diodes and Z-pinches 2002 IEEE [12]
3. A.A.Kim 1 MV ultra-fast LTD generator 2003 IEEE [13]
4. M.G.Mazarakis High Current Fast 100-NS LTD Driver Development in Sandia Laboratory 2005 IEEE [14]
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 [15]
6. M.G. Mazarakis Linear Transformer Driver (LTD) development at Sandia national laboratory 2009 IEEE [16]
7. J.R.Woodworth Low-inductance gas switches for linear transformer drivers Phys. Rev. ST Accel. Beams 12, 060401 (2009) [17]
8. W.A.Stygar Shaping the output pulse of a linear-transformer-driver module Phys. Rev. ST Accel. Beams 12, 030402 (2009) [18]
9. A.A. Kim Development and tests of fast 1-MA linear transformer driver stages Phys. Rev. ST Accel. Beams 12, 050402 (2009) [19]
10. M.G. Mazarakis High current, 0.5-MA, fast, 100-ns, linear transformer driver experiments Phys. Rev. ST Accel. Beams 12, 050401 (2009) [20]
11. M.G. Mazarakis High-Current Linear Transformer Driver Development at Sandia National Laboratories 2010 IEEE [21]
12. J. R. Woodworth Compact 810 kA linear transformer driver cavity Phys. Rev. ST Accel. Beams 14, 040401 (2011) [22]