A four-detector spectrometer for e−−γ PAC on-line with the ISOLDE-CERN isotope separator

Marques, J.G.; Correia, J. G.; Melo, A.A.; Silva, M.F. da; Soares, J.C.

doi:10.1016/0168-583x(94)00591-5

Cited by 25 publications

(11 citation statements)

References 6 publications

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“…The e − γ correlation measurements were carried out in a set-up described in [8]. The probe 111m Cd was chosen, because it "simulates" an EC after ef fect.…”

Section: Methodsmentioning

confidence: 99%

An In-defect complex as a possible explanation for high luminous efficacy of InGaN and AlInN based devices

et al. 2010

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The role of indium in GaN and AlN films is investigated with the method of the perturbed angular correlation (PAC). Using the PAC probe 111 In in addition to indium on substitutional cation sites a large fraction of probes is found in a distinctly different microscopic environment which was attributed to the formation of an indium nitrogen-vacancy (V N ) complex. The influence of an electron capture induced after ef fect is ruled out by additional measurements with the PAC probes 111m Cd and 117 Cd and using GaN with different dopants. It is shown that the V N is not bound to substitutional Cd impurities suggesting that the In-V N complex formation is a particularity of In in GaN and AlN. Finally, a preliminary model is presented to explain the temperature behavior of the electric field gradient, observed in the In-V N complex measured with 111 In.This work reports on PAC measurements in InGaN and AlInN using Cd-111m and Cd-117 probes. The results show that a signal previously observed using In-111 arises from an In-nitrogen-vacancy complex and is not influenced by an electronic aftereffect. The background, experimental method, and results are all described well. In short, the work reported is of high quality, and I recommend the manuscript for publication without modification.

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“…The e − γ correlation measurements were carried out in a set-up described in [8]. The probe 111m Cd was chosen, because it "simulates" an EC after ef fect.…”

Section: Methodsmentioning

confidence: 99%

An In-defect complex as a possible explanation for high luminous efficacy of InGaN and AlInN based devices

et al. 2010

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“…36) or two BaF 2 detectors with two magnetic lenses in a plane at 90-deg intervals for e − − γ PAC. 37 Equation (1) is used to calculate the time differential anisotropy RðtÞ from the coincidence spectra Nðθ; tÞ, where θ is the angle between detectors and t is the time delay between events:…”

Section: Experimental Techniquesmentioning

confidence: 99%

Lattice location of Hf and its interaction with other impurities in LiNbO3: a review

Marques

Lorenz

2014

Opt. Eng

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Abstract. Lithium niobate, LiNbO3, exists in a wide range of compositions, from congruent to stoichiometric. Undoped congruent LiNbO3 suffers from a relatively low optical damage threshold that constitutes its major disadvantage for optoelectronic devices. The optical damage threshold is dependent on the amount of intrinsic defects and is considerably increased in stoichiometric material and in congruent material doped with specific impurities, such as Mg, In, Sc, and Zn. It has been recently shown that the doping with Hf leads to a significant increase of the photorefractive resistance at a threshold concentration of about 3 mol%. The study of the lattice location of Hf in LiNbO3 and its interaction with other impurities and intrinsic defects started more than a decade before the discovery of the role of this impurity, as Hf was a convenient probe for combined studies using the nuclear techniques perturbed angular correlations and Rutherford backscattering spectrometry/channeling. An integrated review of the main results obtained with these techniques is presented. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. [DOI: 10.1117/1.OE.53.6.060901

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“…The conversion electrons are energy discriminated by magnetic lenses prior to the detection on plastic scintillators. This method provides an easy and ecient way to select the electrons of interest from complex decay cascades or from isobaric contamination [9]. Since good time resolution is essential in PAC experiments, cylindrical 1.75 in.…”

Section: Methodsmentioning

confidence: 99%

On-line perturbed angular correlation studies with the short lived 127Cs probe

Correia

Marques²,

Melo³

et al. 1999

Nuclear Instruments and Methods in Physics Research Section B:

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On-line Perturbed Angular Correlation (PAC) experiments were performed on the 66.0 keV excited state of 127 Cs, using the c (114.7 keV)±e À L (66.0 keV) cascade from the decay of the short-lived 127 Ba (T 1a2 13 min) isotope produced at the ISOLDE facility at CERN. The PAC experiments were performed with an optimized c±e À spectrometer coupled to the ISOLDE beam line, which allowed simultaneous implantation and measurement. The optimization of the experiment is described and the ®rst results on metallic foils and single crystals of Al, Be, Ga, Zn, and Ni are presented and discussed. The derived nuclear moments of the 66.0 keV excited state of 127 Cs are jlj 2X92l N and jj 0X5812. Applications of this new PAC isotope are outlined. Ó

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A four-detector spectrometer for e−−γ PAC on-line with the ISOLDE-CERN isotope separator

Cited by 25 publications

References 6 publications

An In-defect complex as a possible explanation for high luminous efficacy of InGaN and AlInN based devices

An In-defect complex as a possible explanation for high luminous efficacy of InGaN and AlInN based devices

Lattice location of Hf and its interaction with other impurities in LiNbO3: a review

On-line perturbed angular correlation studies with the short lived 127Cs probe

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