Pulse power for future and past X-ray simulators

Smith, I.; Corcoran, Patrick; Miller, A.R.; Carboni, V.; Sincerny, P.; Spence, P.; Gilbert, C.; Rix, W.; Waisman, E.; Schlitt, L.; Bell, D.

doi:10.1109/tps.2002.805319

Cited by 17 publications

(5 citation statements)

References 9 publications

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“…Hence, it would appear that a substantial improvement in the performance of an LTD module is possible by using a timing sequence that satisfies Eq. (14). However, as suggested by Fig.…”

Section: Pulse Shaping Whenmentioning

confidence: 59%

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Shaping the output pulse of a linear-transformer-driver module

Stygar

Fowler

LeChien

et al. 2009

Phys. Rev. ST Accel. Beams

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We demonstrate that a wide variety of current-pulse shapes can be generated using a linear-transformerdriver (LTD) module that drives an internal water-insulated transmission line. The shapes are produced by varying the timing and initial charge voltage of each of the module's cavities. The LTD-driven accelerator architecture outlined in [Phys. Rev. ST Accel. Beams 10, 030401 (2007)] provides additional pulseshaping flexibility by allowing the modules that drive the accelerator to be triggered at different times. The module output pulses would be combined and symmetrized by water-insulated radial-transmission-line impedance transformers [Phys. Rev. ST Accel.

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“…Hence, it would appear that a substantial improvement in the performance of an LTD module is possible by using a timing sequence that satisfies Eq. (14). However, as suggested by Fig.…”

Section: Pulse Shaping Whenmentioning

confidence: 59%

“…Kim and colleagues consider instead an LTD module that drives an internal oil-insulated transmission line [9]; Corcoran, Smith, and co-workers [10,14] consider the use of an internal water-insulated line. Reference [37] is the first to propose that water-insulated LTD modules be used to drive next-generation pulsed-power accelerators.…”

Section: Introductionmentioning

confidence: 99%

Shaping the output pulse of a linear-transformer-driver module

Stygar

Fowler

LeChien

et al. 2009

Phys. Rev. ST Accel. Beams

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“…The High Energy Density Physics (HEDP) community is proposing to build a next-generation pulsed-power accelerator with peak electrical output power in the range of 300 TW to 1,000 TW [1][2][3][4][5][6]. The prime power source of such a machine may consist of a system of linear transformer drivers (LTDs) [7][8][9][10][11][12][13][14][15][16][17][18] fast Marx generators (FMGs) [7,9,[19][20][21][22] or impedance-matched Marx generators (IMGs) [18,23,24]. The pulsed power community has been developing LTD technology for 20 years on various single-cavity experiments [16,[25][26][27][28][29][30][31][32][33][34][35][36][37], multicavity (single "module") experiments [14,27,32,35,[38][39]…”

Section: Introductionmentioning

confidence: 99%

100 GW linear transformer driver cavity: Design, simulations, and performance

Douglass¹,

Hutsel²,

Leckbee³

et al. 2018

Phys. Rev. Accel. Beams

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Herein we present details of the design, simulation, and performance of a 100-GW linear transformer driver (LTD) cavity at Sandia National Laboratories. The cavity consists of 20 "bricks." Each brick is comprised of two 80 nF, 100 kV capacitors connected electrically in series with a custom, 200 kV, threeelectrode, field-distortion gas switch. The brick capacitors are bipolar charged to AE100 kV for a total switch voltage of 200 kV. Typical brick circuit parameters are 40 nF capacitance (two 80 nF capacitors in series) and 160 nH inductance. The switch electrodes are fabricated from a WCu alloy and are operated with breathable air. Over the course of 6,556 shots the cavity generated a peak electrical current and power of 1.03 MA (AE1.8%) and 106 GW (AE3.1%). Experimental results are consistent (to within uncertainties) with circuit simulations for normal operation, and expected failure modes including prefire and latefire events. New features of this development that are reported here in detail include: (1) 100 ns, 1 MA, 100-GW output from a 2.2 m diameter LTD into a 0.1 Ω load, (2) high-impedance solid charging resistors that are optimized for this application, and (3) evaluation of maintenance-free trigger circuits using capacitive coupling and inductive isolation.

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“…Large-area water-insulated electrical components are often incorporated in the designs of multiterawatt pulsedpower accelerators, such as the Z [1-10] and ZR [11] machines. Water-insulated components are also proposed for use in future accelerators [12][13][14][15][16][17][18][19]. Optimizing the design of such an accelerator requires a knowledge of the conditions under which its water-insulated components can be operated reliably.…”

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confidence: 99%

Dielectric-breakdown tests of water at 6 MV

Stygar

Savage

Wagoner

et al. 2009

Phys. Rev. ST Accel. Beams

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We have conducted dielectric-breakdown tests on water subject to a single unipolar pulse. The peak voltages used for the tests range from 5.8 to 6.8 MV; the effective pulse widths range from 0.60 to 1:1 s; and the effective areas tested range from 1:8 Â 10 5 to 3:6 Â 10 6 cm 2 . The tests were conducted on waterinsulated coaxial capacitors. Large-area water-insulated electrical components are often incorporated in the designs of multiterawatt pulsedpower accelerators, such as the Z [1-10] and ZR [11] machines. Water-insulated components are also proposed for use in future accelerators [12][13][14][15][16][17][18][19]. Optimizing the design of such an accelerator requires a knowledge of the conditions under which its water-insulated components can be operated reliably.Reference [20] proposes that the characteristic time delay delay between the application of a voltage to a water-insulated anode-cathode gap, and the completion of dielectric failure of that gap, can be approximated as follows:In this expression stat is the statistical component of the delay time; i.e., the characteristic time between the application of the voltage and the appearance of free electrons and ions that initiate the formation of streamers in the water. We define form to be the formative component: the time required for the streamers to propagate across the gap and evolve sufficiently to produce complete dielectric failure.To inhibit electrical breakdown, water-insulated components are usually designed to produce a nominally uniform electric field over most of the component's area. We assume that, when the area of a water-insulated system with a uniform field is sufficiently large, the appearance of free electrons and ions necessary to initiate a breakdown occurs somewhere in the system very early in the voltage pulse [20]. Under this condition the statistical time delay stat can be neglected, and the breakdown delay is dominated by its formative component:In principle, dielectric breakdown dominated by the formative component can be studied with an electrode geometry that consists of a point anode and a planar cathode [20][21][22]. Although measurements with an infinitely field-enhanced anode point and an infinitely extended flat cathode are not possible, a number of dielectric-breakdown measurements between a significantly field-enhanced anode electrode and a less-enhanced cathode have been described in the literature.Using these measurements, Ref.[20] finds that complete dielectric failure is likely to occur in water between a fieldenhanced anode and a less-enhanced cathode when In this expression E p V p =d is the peak value in time of the spatially averaged electric field between the anode and cathode (in MV=cm, where V p is the peak voltage difference and d is the minimum distance between the electrodes), and eff is the temporal width (in s) of the voltage pulse at 63% of peak. This relation is based on 25 measurements for which 1 V p 4:10 MV, 1:25 d 22 cm, and 0:011 eff 0:6 s.To develop a tentative design criterion for a large-area...

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Pulse power for future and past X-ray simulators

Cited by 17 publications

References 9 publications

Shaping the output pulse of a linear-transformer-driver module

Shaping the output pulse of a linear-transformer-driver module

100 GW linear transformer driver cavity: Design, simulations, and performance

Dielectric-breakdown tests of water at 6 MV

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