Measurements and analysis of bremsstrahlung x-ray spectrum obtained in NANOGAN electron cyclotron resonance ion source

Baskaran, R.; Selvakumaran, T. S.; Rodrigues, G.; Kanjilal, D.; Roy, A.

doi:10.1063/1.2816785

Cited by 8 publications

(4 citation statements)

References 8 publications

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“…The Nanogan ECR source [23][24][25] has an all permanent magnetic confinement using NdFeB structure where the electrons diffuse from the high-pressure injection side to the low-pressure extraction side within the confined plasma. In order to confine the plasma in all possible directions, the magnetic field due to a Halbach type multipole increases radially towards the chamber walls for radial confinement and a longitudinal field due to solenoids creates magnetic mirror configuration with loss cone at the extraction side of the ion source.…”

Section: Experimental Detail and Observationsmentioning

confidence: 99%

Experimental investigation of plasma instabilities by Fourier analysis in an electron cyclotron resonance ion source

Kumar

Sharma

et al. 2018

Phys. Rev. Accel. Beams

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The plasma instabilities play an important role in an electron cyclotron resonance (ECR) ion source for the production of intense heavy ion beams in high charge states for particle accelerators. The geometrical and operational constraints of ECR sources hinder the trapping of ions for a sufficient time to get fully ionized with maximum efficiency. This problem is looked at in detail by studying the plasma instabilities in ECR ion sources. The ECR environment is full of complex rearrangements of various electric and magnetic fields to define a sustainable trap for the ions. The maximum frequency of plasma instability has been observed to be of 122.5 kHz under a set of sustainable plasma parameters. However, this limit may be pushed further if the plasma is overdriven in terms of source parameters. The instabilities cover a full regime of few tens of Hz to few hundreds of kHz under various operating conditions of radio frequency (rf), negative bias voltage, rf power and injection gas pressure. The rigorous details of frequencies and amplitudes of plasma instabilities are being reported by studying the Fourier spectrum of extracted and analyzed beam intensity. The plasma instabilities are attributed as drift waves in an inhomogeneous ECR plasma generated by the application of radio-frequency fields.

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Section: Experimental Detail and Observationsmentioning

confidence: 99%

Experimental investigation of plasma instabilities by Fourier analysis in an electron cyclotron resonance ion source

Kumar

Sharma

et al. 2018

Phys. Rev. Accel. Beams

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show abstract

“…These studies can be characterised based on whether or not the obtained results provide spatially and/or temporally resolved information, as well as based on the origin of the measured bremsstrahlung (plasma emission, thick target radiation induced by escaping electrons). Techniques resulting to volume integrated and time averaged results have been used most widely to probe the general plasma properties [6][7][8][9][10][11][12][13][14][15][16], but there has been also significant development in the use of spatially [17,18] and temporally [19] resolved methods. However, unambiguous de-convolution of either thick-target (wall) or plasma bremsstrahlung spectra to obtain the electron energy distribution (EED) of the escaping or confined electrons is seemingly impossible despite some notable efforts [13,20,21].…”

Section: Introductionmentioning

confidence: 99%

Correlation of bremsstrahlung and energy distribution of escaping electrons to study the dynamics of magnetically confined plasma

Bhaskar¹,

Koivisto²,

Tarvainen³

et al. 2021

Plasma Phys. Control. Fusion

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A combination of electron and bremsstrahlung diagnostics was used to study the properties of the highly charged plasma of an electron cyclotron resonance ion source (ECRIS). The bremsstrahlung radiation in both axial and radial directions was correlated with the energy distribution of the electrons escaping axially from the confined plasma, i.e. the lost electron energy distribution (LEED), to achieve a more comprehensive view of the plasma. The evolution of the bremsstrahlung spectra and the LEED were determined as a function of the main operating parameters of the ion source. Also, the effects of the transition from a stable to an unstable plasma regime were determined for the bremsstrahlung and LEED changes in the shape of the measured LEED were found to correlate with changing bremsstrahlung spectral temperature. It was also found that the magnetic field has a strong impact on the axial and radial bremsstrahlung spectra and the LEED affecting the bremsstrahlung intensity, spectral temperatures and the LEED high energy local maximum. A comprehensive discussion is provided to explain the observed different behaviour of axial and radial bremsstrahlung emissions with varying magnetic field based on the directionality of plasma bremsstrahlung in ECRIS specific magnetic confinement scheme. Furthermore, it was observed that the onset of kinetic plasma instabilities has a clear impact on the shape of the LEED

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“…This article deals with experimental studies of the hot electron population of a highly charged ECR ion source. As collisions between electrons and ions within the plasma volume lead to bremsstrahlung radiation, the analysis of bremsstrahlung spectra is a powerful diagnostic tool for studying the hot electron population [22,23] and can also be used to probe the electron heating mechanism in ECR produced plasmas, from compact all-permanent magnet [24] to large fully superconducting devices [13,25]. To compare our results with previous articles published on the same subject, bremsstrahlung measurement was chosen to diagnose the plasma of SECRAL-II ion source.…”

Section: Introductionmentioning

confidence: 99%

Effects of magnetic configuration on hot electrons in a minimum-B ECR plasma

Bhaskar

et al. 2020

Plasma Phys. Control. Fusion

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To investigate the hot electron population and the appearance of kinetic 18 instabilities in highly charged electron cyclotron resonance ion source (ECRIS), the 19 axially emitted bremsstrahlung spectra and microwave bursts emitted from ECRIS 20 plasma were synchronously measured on SECRAL-II (Superconducting ECR ion source 21 with Advanced design in Lanzhou No. II) ion source with various magnetic field 22 configurations. The experimental results show that when the ratio of the minimum 23 field to the resonance field (i.e. B min /B ecr ) is less than ~0.8, the bremsstrahlung 24 42

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Measurements and analysis of bremsstrahlung x-ray spectrum obtained in NANOGAN electron cyclotron resonance ion source

Cited by 8 publications

References 8 publications

Experimental investigation of plasma instabilities by Fourier analysis in an electron cyclotron resonance ion source

Experimental investigation of plasma instabilities by Fourier analysis in an electron cyclotron resonance ion source

Correlation of bremsstrahlung and energy distribution of escaping electrons to study the dynamics of magnetically confined plasma

Effects of magnetic configuration on hot electrons in a minimum-B ECR plasma

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