Data on pure tin by Positron Annihilation Lifetime Spectroscopy (PALS) acquired with a semi-analog/digital setup using DDRS4PALS

Petschke, Danny; Helm, Ricardo; Staab, T.E.M.

doi:10.1016/j.dib.2018.11.121

Cited by 6 publications

(2 citation statements)

References 11 publications

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“…These lifetimes and spectra (Figures S7-S9) are well-described by a tri-exponential model function relaxing in 100 ps, in 400 ps and about 1 ns respectively as shown by the fitted curve in Supplementary Figure S8. The values measured here seem to be on average lower than those given by the manufacturer, but are relatively comparable to those measured by coincidence at 200 and 380 ps 21 . For comparison purposes, the UV excitation data were not deconvoluted for the instantaneous response function, because this function cannot be measured for the electron beam (this would require a scintillator with a calibrated lifetime in the ps range).…”

Section: Electron-induced Compared To Uv-induced Luminescencesupporting

confidence: 59%

Time-resolved cathodoluminescence of DNA triggered by picosecond electron bunches

Renault

Lucas

Gustavsson

et al. 2020

Sci Rep

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Despite the tremendous importance of so-called ionizing radiations (X-rays, accelerated electrons and ions) in cancer treatment, most studies on their effects have focused on the ionization process itself, and neglect the excitation events the radiations can induce. Here, we show that the excited states of DnA exposed to accelerated electrons can be studied in the picosecond time domain using a recently developed cathodoluminescence system with high temporal resolution. our study uses a table-top ultrafast, UV laser-triggered electron gun delivering picosecond electron bunches of keV energy. this scheme makes it possible to directly compare time-resolved cathodoluminescence with photoluminescence measurements. This comparison revealed qualitative differences, as well as quantitative similarities between excited states of DnA upon exposure to electrons or photons. Most studies on the effect of so-called ionizing radiations (X-rays, electrons, ions) have focused on the ionization process itself. However, ionizing radiation can also efficiently induce excitations in various molecules, whose effects are rarely studied in radiation chemistry and biochemistry. In particular, there is very little literature on the excited state dynamics of DNA following the initial energy deposition by charged particles. For example, highly energetic excited states can be produced by energetic electrons (as suspected from electron energy-loss spectroscopy on DNA 1,2 , showing a "plasmon band" at 25 eV) with expected, associated short lifetimes 3 , and putative damaging effects when they cause molecular reorganization. Furthermore, such states may migrate, potentially changing the dose distribution locally. One way to identify and study such states is to analyse their luminescence. The luminescence of DNA under ionizing radiations (also called scintillation) has been reported in the literature-albeit scarcely-especially at low temperatures. For instance, in frozen DNA, a microsecond 4.3 MeV electron excitation induced a "short-lived" emission extending up to 530 nm 4. More recently, "in-pulse" nanosecond (ns) luminescence spectra of irradiated (260 keV electrons) wet and dry DNA 5-7 showed the same broad emission that is sensitive to the presence of energy or electron traps. A negligible amount of light is emitted after the ns pulse, leading to the suggestion that excited states form by geminate recombination of electrons and holes and/or by direct excitation, with sub-ns relaxation times. Further progress on this topic has been impaired by the lack of appropriate time-resolved sources of ionizing radiation. The so-called pulsed radiolysis technique relies on a high-energy particle accelerator, which has two drawbacks 4 : (i) it has a low repetition rate (a few hundred Hz at the most) that is not compatible with ultrafast time-resolved techniques, such as time-correlated single photon counting, and limits the time resolution to the ns range 8 ; (ii) it provides high-energy beams that produce Cerenkov light, which blinds the detector 9,10...

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Section: Electron-induced Compared To Uv-induced Luminescencesupporting

confidence: 59%

Time-resolved cathodoluminescence of DNA triggered by picosecond electron bunches

Renault

Lucas

Gustavsson

et al. 2020

Sci Rep

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“…The spectra presented here were acquired in a colinearly arranged (180 • ) two-detector (2D) configuration setup as described elsewhere by the authors [7]. DDRS4PALS v1.08 [8,9] served as a software tool for the acquisition and simulation of the lifetime spectra, where the integrated simulation functionality is provided by DLTPulseGenerator library (v1.3) [10][11][12][13].…”

Section: Experimental Setup and Lifetime Spectra Acquisition And Analysis Softwarementioning

confidence: 99%

Limitations on the Positron Lifetime Spectra Decomposability Applying the Iterative Least-Square Re-Convolution Method Using the Instrumental Responses Obtained from ²⁰⁷Bi and ⁶⁰Co

Petschke

Helm

Haaks³

et al. 2020

Acta Phys. Pol. A

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Since the decomposition of positron lifetime spectra requires solving an ill-posed and inverse problem, the accurate knowledge of the spectrometer's instrument response function is crucial for extracting the true underlying physical information of the phenomenon under investigation. In general, the instrument response function is modelled by a superposition of Gaussian functions, since an analytical solution for the convolution with an exponential distribution function exists and, hence, the characteristic lifetimes and its corresponding contributions can be obtained by non-linear least-squares fitting. In contrast, the iterative least-squares re-convolution approach determines the best fit of the recorded lifetime spectrum by re-convoluting a sum of N expected exponential decays with the numerical data of the experimentally obtained instrument response function. For a laboratory setup, two methods exist to estimate the shape of the instrument response function from experiment: (1) the direct method using a 60 Co isotope and an indirect method by graphically deconvoluting the monoexponential lifetime spectrum obtained from 207 Bi. For both variants, the energies of the incident gamma-rays are considerably different to the energies accompanying the creation (1274 keV) and annihilation (511 keV) of a positron using 22 Na: 60 Co (1173 keV, 1333 keV), 207 Bi (570 keV, 1064 keV). Here we present a detailed study on the basis of plastic scintillators regarding the spectra decomposability by using the re-convolution technique with experimentally obtained instrument response functions. We can clearly show that beyond incident gamma-ray energy differences, the Compton scattering effects and pile-up events represent the limiting factors in this approach.

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A supervised machine learning approach using naive Gaussian Bayes classification for shape-sensitive detector pulse discrimination in positron annihilation lifetime spectroscopy (PALS)

Petschke

Staab

2019

Nuclear Instruments and Methods in Physics Research Section A:

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Data on pure tin by Positron Annihilation Lifetime Spectroscopy (PALS) acquired with a semi-analog/digital setup using DDRS4PALS

Cited by 6 publications

References 11 publications

Time-resolved cathodoluminescence of DNA triggered by picosecond electron bunches

Time-resolved cathodoluminescence of DNA triggered by picosecond electron bunches

Limitations on the Positron Lifetime Spectra Decomposability Applying the Iterative Least-Square Re-Convolution Method Using the Instrumental Responses Obtained from ²⁰⁷Bi and ⁶⁰Co

A supervised machine learning approach using naive Gaussian Bayes classification for shape-sensitive detector pulse discrimination in positron annihilation lifetime spectroscopy (PALS)

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Data on pure tin by Positron Annihilation Lifetime Spectroscopy (PALS) acquired with a semi-analog/digital setup using DDRS4PALS

Cited by 6 publications

References 11 publications

Time-resolved cathodoluminescence of DNA triggered by picosecond electron bunches

Time-resolved cathodoluminescence of DNA triggered by picosecond electron bunches

Limitations on the Positron Lifetime Spectra Decomposability Applying the Iterative Least-Square Re-Convolution Method Using the Instrumental Responses Obtained from 207Bi and 60Co

A supervised machine learning approach using naive Gaussian Bayes classification for shape-sensitive detector pulse discrimination in positron annihilation lifetime spectroscopy (PALS)

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Limitations on the Positron Lifetime Spectra Decomposability Applying the Iterative Least-Square Re-Convolution Method Using the Instrumental Responses Obtained from ²⁰⁷Bi and ⁶⁰Co