Ionoluminescent response of several phosphor screens to keV ions of different masses

This work extends a previous study on ionoluminescence of a radiation-hard ceramic scintillator, Al(2)O(3):Cr, to ions accelerated to keV energies [K. J. McCarthy et al., J. Nucl. Mater. 321, 78 (2003)]. It is motivated by the identification of this material as a promising candidate for use in the fast-ion-loss detector for ITER [for the range of thermal (low energy) and suprathermal ions]. In the paper we quantify and compare its ionoluminescence with that of some common luminescent materials (YAG:Ce and ruby) when irradiated by H(+) ions accelerated to < or = 60 keV using a purpose built laboratory setup. Next, studies are made on the ceramic to quantify its response as a function of incident ion mass, i.e., to He(+). For this, the absolute luminosities of the material are estimated in terms of the number of photons emitted per incident ion as a function of energy. Moreover, the radiation hardness and postirradiation recovery of the ceramic are investigated. Finally, from the studies it can be concluded that the ceramic ruby is a good candidate for detecting low energy ions as long as its temporal response (approximately several milliseconds) is not a constraint for specific ion measurements.

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“…9, it has undergone some modifications since then. 9, it has undergone some modifications since then.…”

Section: Methodsmentioning

confidence: 99%

“…Inc., Font Collins, CO͒. 9. Hence, some corrections, as determined by modeling, are needed when estimating beam currents for H + and He + ions.…”

Section: Methodsmentioning

confidence: 99%

The response of a radiation resistant ceramic scintillator (Al2O3:Cr) to low energy ions (–60keV)

Jiménez-Rey

Zurro

McCarthy

et al. 2008

Review of Scientific Instruments

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“…It allows particles with pitch angles from approximately 20° to 80° to be detected. The phosphor powder screen used is YAP:Ce (Yttrium Aluminium Perovskite doped with cerium, decay time = 27 ns), the screen was prepared in‐house using a sedimentation method to deposit a uniform layer on a 25.4 mm diameter stainless steel plate . This phosphor was chosen because of its good sensitivity and linearity in the energy range of interest for ion‐induced luminescence.…”

Section: Experiments and Lp Set‐upmentioning

confidence: 99%

Discrete fast‐ion detection with energy discrimination in plasmas having edge‐localized mode‐like instabilities in the stellarator TJ‐II

Martínez

Zurro²,

Baciero³

et al. 2018

Contributions to Plasma Physics

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The existence of a population of ions, with energies well above the corresponding thermal values, in plasmas heated by neutral beam injection (NBI) in the stellarator TJ-II and in other magnetically confined plasmas devices is well known. Moreover, during the NBI phase of the TJ-II, edge-localized mode-like (ELM-like) instabilities often appear. This work studies the relationship between fast ions escaping from TJ-II plasmas and such ELM-like events. For this, an ion luminescent probe (LP), operated with a fast scintillator (decay time = 27 ns) and high-speed conditioning electronics (100 MHz), is used to measure, without pile-up effects, the energy distribution of suprathermal ions across the energy range, from 1 to 30 keV. It is found that the LP detects suprathermal ion populations that can be related to ELM-like events whose temperatures oscillate between 0.5 and 3 keV and that can be distinguished in a spectrogram of the LP response as an increase in frequencies from 15 to 150 kHz. Finally, observations of substructures within ELM-likes events, consisting of bursts of ions, with times between 5 and 15 μs are also reported. Such substructures have been observed previously in both tokamaks and stellarators in ion saturation current, high-speed camera images, etc. However, understanding the fast-ion component can provide new and relevant information about the behaviour of ions.

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“…A uniform screen, deposited on a 25 mm diameter stainless steel plate, was prepared using a sedimentation method, explained in more detail in Ref. 12, to obtain a screen density of approximately 17.59 mg cm −2 . The luminescent centers are Tb +3 ions uniformly distributed in the Y 2 O 2 S host lattice.…”

Section: Luminescence Screenmentioning

confidence: 99%

“…To help calibrate the TJ-II measurements, a benchtop setup was developed in parallel to perform basic studies on the response of the phosphor screen in the ion energy range of interest ͑E Յ 35 keV͒. 12 In the past, the efficiency of phosphor screens to vacuum ultraviolet radiation, x rays and electrons has been studied extensively, but the response to ions in the energy range of interest for a FILD in fusion plasmas was unknown. This limitation has constrained the use of this type of detector to applications that did not require knowledge of the screen's ionoluminescent response with energy, for instance, the correlation of fast ions escaping with MHD plasma activity 3,9 or comparative measurements of ion impact position with ion energy.…”

Section: Introductionmentioning

confidence: 99%

A flexible luminescent probe to monitor fast ion losses at the edge of the TJ-II stellarator

Jiménez-Rey

Zurro

Guasp

et al. 2008

Review of Scientific Instruments

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A mobile luminescent probe has been developed to detect fast ion losses and suprathermal ions escaping from the plasma of the TJ-II stellarator device. The priorities for its design have been flexibility for probe positioning, ease of maintenance, and detector sensitivity. It employs a coherent fiber bundle to relay, to the outside of the vacuum chamber, ionoluminescence images produced by the ions that impinge, after entering the detector head through a pinhole aperture, onto a screen of luminescent material. Ionoluminescence light detection is accomplished by a charge-coupled device camera and by a photomultiplier, both of which are optically coupled to the in-vacuum fiber bundle head by means of a standard optical setup. A detailed description of the detector, and the first results obtained when operated close to the plasma edge, are reported.

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Ionoluminescent response of several phosphor screens to keV ions of different masses

Cited by 19 publications

References 23 publications

The response of a radiation resistant ceramic scintillator (Al2O3:Cr) to low energy ions (–60keV)

The response of a radiation resistant ceramic scintillator (Al2O3:Cr) to low energy ions (–60keV)

Discrete fast‐ion detection with energy discrimination in plasmas having edge‐localized mode‐like instabilities in the stellarator TJ‐II

A flexible luminescent probe to monitor fast ion losses at the edge of the TJ-II stellarator

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