Comparative Study of γ- and e-Radiation-Induced Effects on FBGs Using Different Femtosecond Laser Inscription Methods

This work presents an extensive, comparative study of the gamma and electron radiation effects on the behaviour of femtosecond laser-inscribed fibre Bragg gratings (FBGs) using the point-by-point and plane-by-plane inscription methods. The FBGs were inscribed in standard telecommunication single mode silica fibre (SMF28) and exposed to a total accumulated radiation dose of 15 kGy for both gamma and electron radiation. The gratings’ spectra were measured and analysed before and after the exposure to radiation, with complementary material characterisation using Fourier transform infrared (FTIR) spectroscopy. Changes in the response of the FBGs’ temperature coefficients were analysed on exposure to the different types of radiation, and we consider which of the two inscription methods result in gratings that are more robust in such harsh environments. Moreover, we used the FTIR spectroscopy to locate which chemical bonds are responsible for the changes on temperature coefficients and which are related with the optical characteristics of the FBGs.

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Comparative Study of Gamma Radiation Effects on Solar Cells, Photodiodes, and Phototransistors

International Journal of Photoenergy ◽

10.1155/2013/843174 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 5

Author(s):

Dejan Nikolić ◽

Koviljka Stanković ◽

Ljubinko Timotijević ◽

Zoran Rajović ◽

Miloš Vujisić

Keyword(s):

Comparative Analysis ◽

Comparative Study ◽

Gamma Radiation ◽

Gamma Irradiation ◽

Radiation Effects ◽

Optoelectronic Devices ◽

Solar Panels ◽

Measurement Results ◽

Before And After ◽

Pin Photodiodes

This paper presents the behavior of various optoelectronic devices after gamma irradiation. A number of PIN photodiodes, phototransistors, and solar panels have been exposed to gamma irradiation. Several types of photodiodes and phototransistors were used in the experiment.I-Vcharacteristics (current dependance on voltage) of these devices have been measured before and after irradiation. The process of annealing has also been observed. A comparative analysis of measurement results has been performed in order to determine the reliability of optoelectronic devices in radiation environments.

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Investigation of radiation induced luminescence with modulated signal transmission in optical fiber

Journal of Optical Communications ◽

10.1515/joc-2020-0287 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Haider A. Kadhum ◽

Mazin Ali A. Ali ◽

Zeyad A. Saleh

Keyword(s):

Optical Fiber ◽

Signal To Noise Ratio ◽

Signal Transmission ◽

Optical Power ◽

Single Mode ◽

Peak Voltage ◽

Dose Rates ◽

Fiber Properties ◽

Before And After ◽

Radiation Induced

Abstract In this work, the effect of mixed beta and gamma radiation on the optical fiber properties was investigated, this effect has been studied for different signal frequencies which range 1–100 kHz carrying on laser beam using amplitude shift key (ASK). Single mode (SM) glass optical fiber was utilized, and exposed by (Cs-137) as radioactive point source with different low dose rates. The variation of received optical power (P r ), peak to peak voltage (Vp-p), voltage gain (A v ), and signal to noise ratio (SNR) were measured before and after irradiation. It was observed that an improvement in the received signals which propagates in optical fiber after irradiation by exposure of lower dose rates.

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Electron beam damage of Ni3Al

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100148964 ◽

1993 ◽

Vol 51 ◽

pp. 626-627

Author(s):

David A. Muller ◽

John Silcox

Keyword(s):

Radiation Damage ◽

Radiation Effects ◽

High Strength ◽

Beam Current ◽

Electron Radiation ◽

Beam Size ◽

Surface Layers ◽

Inhibiting Effect ◽

Radiation Induced ◽

Beam Damage

In recent years, the effect of radiation induced sputtering in electron microscopy at voltages as low as 100 kV has been identified and has emerged as a significant factor in microanalysis. The inhibiting effect of some surface layers has also been noted. More generally, the use of focused electron probes (as in STEM) as a tool for materials modification on the nanoscale has also been developed. We report here observations of electron radiation effects in Ni3Al, a proto-typical high temperature, high strength intermetallic of some considerable interest. This work is comparable to the study of electron radiation damage in aluminium reported by Bullough et.al.Fig. 1 illustrates the formation of holes in a Ni3Al specimen and the associated nickel rich patches formed after irradiation at 100kV in the Cornell UHV HB501A STEM in spot mode with an estimated 10Å FWHM beam size at a beam current of 0.12 nA for a period of 20 minutes. The somewhat dramatic radiation damage is readily seen.

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Electrical Characterization of Commercial Power MOSFET Under Electron Radiation

Indonesian Journal of Electrical Engineering and Computer Science ◽

10.11591/ijeecs.v8.i2.pp462-466 ◽

2017 ◽

Vol 8 (2) ◽

pp. 462

Author(s):

Wan Nurhasana binti Wan Ayub ◽

Nurul Fadzlin Hasbullah ◽

Abdul Wafi Rashid

Keyword(s):

Dose Level ◽

Electron Irradiation ◽

Threshold Voltage ◽

Electrical Characterization ◽

Electron Radiation ◽

Power Mosfet ◽

Before And After ◽

Radiation Induced ◽

Oxide Traps

<p>This paper presents the threshold voltage shifts for both p-channel and n-channel commercial power MOSFET before and after electron irradiation. The experiment was done under the 3MeV energy of electron with dose level varies from 50KGy until 250KGy. The results were plotted and analyzed in terms of the shifted voltage characteristics. It is observed that after irradiation, both p-channel and n-channel MOSFET experiences negative threshold voltage shifts. For n-channel devices, this is due to the radiation-induced positive charges dominated in the oxide traps while for p-channel devices it is believed due to radiation-induced ionization damage.</p>

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Phosphors as Sensors for Radiation-Induced Displacement Damage

MRS Proceedings ◽

10.1557/opl.2012.1298 ◽

2012 ◽

Vol 1471 ◽

Author(s):

S. L. Gollub ◽

R. R. Harl ◽

S. L. Weeden-Wright ◽

B. R. Rogers ◽

D. G. Walker

Keyword(s):

Radiation Effects ◽

Spectral Signature ◽

X Rays ◽

Displacement Damage ◽

Particle Radiation ◽

Before And After ◽

Radiation Induced ◽

Significant Change ◽

Alpha Irradiation ◽

Rule Out

AbstractThe radiation-induced displacement damage in yttrium borate (YBO3) is studied under X-ray, proton, and alpha irradiation. The photoluminescence (PL) was tested before and after irradiation to determine whether damage occurred and whether it could be queried by examining the PL spectrum. Two different dopants (cerium and europium) were used to activate the phosphor because each provides not only a different spectral signature but also a different mechanism for altering the spectrum between the pre- and post-PL measurements. X-rays, being primarily ionizing radiation, did not show any significant change between the pre and post measurements. We expected protons and alphas to damage the crystal structure, evidence of which could be seen in the change in the spectra before and after irradiation. However, we found no change under alpha exposure (3.6 × 1010 particles/cm2) and a significant change after proton exposure (5 × 1015 particles/cm2). While the material appears to be sensitive to protons, we cannot rule out its sensitivity to alphas because the alpha fluence may be too low to show an effect. This result provides strong indication that our materials are being damaged by particle radiation and that the radiation effects can be quantified.

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Radiation Effects in Rare-Earth Permanent Magnets

MRS Proceedings ◽

10.1557/proc-96-321 ◽

1987 ◽

Vol 96 ◽

Cited By ~ 19

Author(s):

J. R. Cost ◽

R. D. Brown ◽

A. L. Giorgi ◽

J. T. Stanley

Keyword(s):

Neutron Irradiation ◽

Radiation Effects ◽

Permanent Magnets ◽

Hysteresis Loops ◽

Open Circuit ◽

Fast Neutrons ◽

Rapid Loss ◽

Before And After ◽

Radiation Induced ◽

Fission Neutrons

ABSTRACTNd-Fe-B and Sm-Co permanent magnets have been irradiated with fission neutrons and gamma rays. Irradiated samples were periodically removed for room temperature measurements of the open-circuit remanence. Hysteresis loops were measured before and after irradiation. For neutron irradiation, two Nd-Fe-B magnets showed a rapid loss of remanence, while a third magnet from another manufacturer decayed more slowly, suggesting that the radiation hardness of Nd-Fe-B magnets may depend on microstructural details. Irradiation in the Omega West Reactor at Los Alamos with fast neutrons caused the fast-decay samples to have an Wtial loss of remanence of 1% for irradiation at 350 K to a fluence of 1015 n/cm2. Both SmCo5 and Sm2Co17 magnets showed excellent resistance to radiatifg-induied loss of remanence for neutron irradiation to a fluence of 2.6×1018 n/cm2. Results for gamma radiation showed no loss of remanence for a dose of about 49 Mrad using a 60Co source. Possible mechanisms for radiation-induced loss of magnetic properties are discussed.

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Comparative study on some oxidative stress parameters in blood of vitiligo patients before and after therapy by two analytical techniques

10.26226/morressier.596dfd57d462b802923872cb ◽

2017 ◽

Author(s):

Dimitar Chonov

Keyword(s):

Oxidative Stress ◽

Comparative Study ◽

Analytical Techniques ◽

Oxidative Stress Parameters ◽

Before And After ◽

Stress Parameters

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Scanning Electron Microscopy Analysis of the Anterior Capsulotomy Edge: A Comparative Study between Femtosecond Laser-Assisted Capsulotomy and Manual Capsulorhexis

Journal of Ophthalmology ◽

10.1155/2018/8620150 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

Daniele Tognetto ◽

Chiara De Giacinto ◽

Alberto Armando Perrotta ◽

Tommaso Candian ◽

Alessandro Bova ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Femtosecond Laser ◽

Comparative Study ◽

Surface Irregularity ◽

Significant Difference ◽

Group 2 ◽

Cut Surface ◽

Scanning Electron ◽

Group 1

Purpose. To compare the capsule edges ultrastructure obtained by two femtosecond laser-assisted cataract surgery (FLACS) platforms and manual continuous curvilinear capsulorhexis (CCC) using scanning electron microscopy (SEM). Setting. Eye Clinic, University of Trieste, Italy. Design. Experimental comparative study. Methods. 150 anterior capsules were collected and divided into three groups as follows: Group 1 (50 capsules) obtained with manual CCC, Groups 2 and 3 (each with 50 capsules) obtained with the Catalys Laser and the LenSx Laser, respectively. All samples were imaged by means of SEM and regularity of the cut surface, and thickness of the capsule edge were evaluated and compared. Results. All femtosecond laser (FSL) capsules were perfectly circular, whereas some alteration of the circular shape was observed in the manual ones. Group 1 showed a smooth and regular capsule edge without any surface irregularity, conversely Groups 2 and 3 showed postage-stamp perforations on the capsule edge. The cut surface irregularity value in Group 2 was 1.4 ± 0.63, while it was 0.7 ± 0.49 in Group 3 (p<0.05). Group 1 had a significantly lower thickness of the capsule edge than the FSL groups (p<0.05). No statistically significant difference in the capsule edge thickness between the FSL groups was found (p=0.244). Conclusions. Despite the presence of slight cut surface irregularities, both FSL capsulotomies showed a better geometry and circularity than the manual ones. Capsulotomy specimens obtained using both FSL capsulotomies showed laser-induced alterations of the capsule edge when compared with smooth and regular edges obtained using manual CCC.

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