High-voltage, high-impedance ion beam production

Hinshelwood, D.D.; Jackson, S. L.; Allen, R.J.; Commisso, R.J.; Cooperstein, G.; Mosher, D.; Murphy, D.P.; Ottinger, P. F.; Schumer, J.W.; Swanekamp, S.B.; Weber, B.V.; Young, F.C.

doi:10.1109/ppc.2009.5386248

Cited by 7 publications

(3 citation statements)

References 6 publications

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“…It consisted of an ion-beam diode coupled to a γ-ray-producing converter and was an extension of earlier work conducted using the Gamble II generator [16]. The ion-beam diode consisted of a convex polyvinyl acetate (PVA) anode and a cylindrical aluminum cathode [17]. Ions from the anode were accelerated towards the cathode and through a thin foil (2-μm-thick Kimfol), then transported 23.8 cm downstream inside an aluminum transport tube to a thick PTFE (Teflon) converter.…”

Section: A Probing Radiation Sourcementioning

confidence: 99%

“…Additional diagnostics were used to obtain other quantities of interest in characterizing the diode [14], [15], [17]. The anode current was measured by several Bdot loops imbedded in the center conductor of the generator, 20 cm upstream of the anode.…”

Section: Additional Diagnosticsmentioning

confidence: 99%

“…During the source characterization, a change was made to the diode to achieve the low neutron yields recorded by the rhodium counters and reported in the previous paragraph [17]. Both the SPMT and a rhodium counter were used to monitor the result of this change.…”

Section: A Characteristics Of Intense Pulsed Source Of γ-Raysmentioning

confidence: 99%

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Detectors for intense, pulsed active detection

Jackson

Allen

Apruzese

et al. 2010

IEEE Nuclear Science Symposuim &Amp; Medical Imaging Conference

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In intense, pulsed active detection, a single, intense pulse of radiation is used to induce photofission in fissionable material, increasing its detectability. The Mercury pulsed-power generator was converted to positive polarity (+3.7 MV, 325 kA, 50-ns FWHM) to drive an intense, pulsed radiation source based on the FIGARO active detection concept. The probing radiation source consisted of an ion-beam diode and a thick PTFE (Teflon) converter where 6 -7 MeV γ-rays were produced via the 19 F(p,αγ) 16 O reaction. A suite of radiation detectors was used both to detect the presence of irradiated fissionable material and to characterize the probing radiation source. Four types of detectors were used for the source characterization. Thermoluminescent dosimeters were used to measure the angular distribution of the dose associated with x-rays and γ-rays from the ion-beam diode. Plastic scintillator-photodiode detectors were used to characterize the time dependence of this dose. A plastic scintillator-photomultiplier detector was used to monitor the γ-ray intensity of the probing radiation source and to monitor changes in the production of background neutrons by the diode and PTFE converter. A set of rhodium foil activation counters was used to measure the absolute yield of these background neutrons. Two types of detectors with comparable sensitivities were used to measure delayed neutrons resulting from photofission: 3 He proportional counters and a 6 Li-loadedglass-scintillator detector. The neutron detection rate from each detector following the probing radiation pulse was over 100 times higher with depleted uranium present than with lead.

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Section: A Probing Radiation Sourcementioning

confidence: 99%

Section: Additional Diagnosticsmentioning

confidence: 99%

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Detectors for intense, pulsed active detection

Jackson

Allen

Apruzese

et al. 2010

IEEE Nuclear Science Symposuim &Amp; Medical Imaging Conference

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Ion diode performance on a positive polarity inductive voltage adder with layered magnetically insulated transmission line flow

et al. 2011

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A pinch-reflex ion diode is fielded on the pulsed-power machine Mercury (R. J. Allen, et al., 15th IEEE Intl. Pulsed Power Conf., Monterey, CA, 2005, p. 339), which has an inductive voltage adder (IVA) architecture and a magnetically insulated transmission line (MITL). Mercury is operated in positive polarity resulting in layered MITL flow as emitted electrons are born at a different potential in each of the adder cavities. The usual method for estimating the voltage by measuring the bound current in the cathode and anode of the MITL is not accurate with layered flow, and the interaction of the MITL flow with a pinched-beam ion diode load has not been studied previously. Other methods for determining the diode voltage are applied, ion diode performance is experimentally characterized and evaluated, and circuit and particle-in-cell (PIC) simulations are performed. Results indicate that the ion diode couples efficiently to the machine operating at a diode voltage of about 3.5 MV and a total current of about 325 kA, with an ion current of about 70 kA of which about 60 kA is proton current. It is also found that the layered flow impedance of the MITL is about half the vacuum impedance.

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