A range-based method to calibrate a magnetic spectrometer measuring the energy spectrum of the backward electron beam of a plasma focus

Abstract

The electron beam emitted from the back of plasma focus devices is being studied as a radiation source for intraoperative radiation therapy applications. A plasma focus device is being developed for this purpose, and there is a need for characterizing its electron beam, particularly, insofar as the energy spectrum is concerned. The instrument used is a magnetic spectrometer. To calibrate this spectrometer, a procedure relying on the energy-range relation in Mylar® has been devised and applied. By measuring the transmission through increasing thicknesses of the material, electron energies could be assessed and compared to the spectrometer readings. Thus, the original calibration of the instrument has been extended to higher energies and also to better accuracy. Methods and results are presented.

Enhancing radiosensitivity of melanoma cells through very high dose rate pulses released by a plasma focus device

“…High-DR (order of 0.2–1 Gy per shot, each shot lasting 20–50 ns) experiments were performed with the PFMA-3 device (Montecuccolino Laboratory, University of Bologna). The Monte Carlo simulation of the X-ray spectrum exhibited a component at 10 keV, and a component at 50 keV with a tail of up to 200 keV [ 32 ]. The dose assessment delivered in each shot has been extensively validated using Gafchromic ® films (EBT2/3) [ 26 ].…”

EBT2 dosimetry of x-rays produced by the electron beam from a Plasma Focus for medical applications

“…2,11 Measurements of the backward electron beam have been conducted by many authors, see, e.g., Refs. 12 and 13, however the results, as is to be expected, are strictly specific to every single device and extrapolation is unfeasible, hence the necessity to repeat the measurements for the device at hand, as reported in Ceccolini et al 14 As mentioned, PFMA-3 is being optimized as an x-ray generator and x-rays are obtained from the conversion of the electron beam, driven through an extraction guide to impinge on a 50 lm brass foil, therefore the need for characterising the electron beam. With this as input, MCNPX simulations were run, and they have shown that the spectrum produced is comprised of two components: one due to characteristic emission centred around 10 keV and one from bremsstrahlung centred around 30 keV and with a tail extending to 150 keV.…”

Analysis and characterization of the X‐ray beam produced by a PF device for radiotherapy applications

“…The intensity of the electron beam was measured to be of the order of 10 15 electrons per discharge . Electrons are emitted during the ~50 ns of the pinch, giving a very high beam intensity, on the order of 10 22 electrons per second.…”

“…The spectrum of the electron beam was measured with a magnetic spectrometer . The measurements are described in Ceccolini et al , to which the interested reader is referred for further details.…”

“…[10] Electrons are emitted during thẽ 50 ns of the pinch, giving a very high beam intensity, on the order of 10 22 electrons per second. The spectrum of the electron beam was measured with a magnetic spectrometer.…”