Calibration of time of flight detectors using laser-driven neutron source

Mirfayzi, S. R.; Kar, S.; Ahmed, H.; Krygier, A.; Green, A.; Alejo, A.; Clarke, R. J.; Freeman, R. R.; Fuchs, Julien; Jung, Daniel; Kleinschmidt, A.; Morrison, John T.; Najmudin, Z.; Nakamura, Hirotaka; Norreys, P.; Oliver, M.; Roth, Markus; Vassura, L.; Zepf, M.; Borghesi, M.

doi:10.1063/1.4923088

Cited by 25 publications

(23 citation statements)

References 31 publications

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“…The angle of observation and distance of each nToF detector is given in figure 1. The nToF detectors were cross-calibrated [19] against the spectra obtained from the BDS, which were absolutely calibrated by the company[17].…”

Section: Methodsmentioning

confidence: 99%

Beamed neutron emission driven by laser accelerated light ions

Kar¹,

Green²,

Ahmed³

et al. 2016

New J. Phys.

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Highly anisotropic, beam-like neutron emission with peak flux of the order of 10 9 n/sr was obtained from light nuclei reactions in a pitcher-catcher scenario, by employing MeV ions driven by a subpetawatt laser. The spatial profile of the neutron beam, fully captured for the first time by employing a CR39 nuclear track detector, shows a FWHM divergence angle of~ 70 , with a peak flux nearly an order of magnitude higher than the isotropic component elsewhere. The observed beamed flux of neutrons is highly favourable for a wide range of applications, and indeed for further transport and moderation to thermal energies. A systematic study employing various combinations of pitchercatcher materials indicates the dominant reactions being d(p, n+p) 1 H and d(d,n) 3 He. Albeit insufficient cross-section data are available for modelling, the observed anisotropy in the neutrons' spatial and spectral profiles is most likely related to the directionality and high energy of the projectile ions.

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Section: Methodsmentioning

confidence: 99%

Beamed neutron emission driven by laser accelerated light ions

Kar¹,

Green²,

Ahmed³

et al. 2016

New J. Phys.

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“…A flux of 10 7 -10 9 neutrons per steradian per pulse were detected. Figure 7 shows the time-of-flight signal recorded by oscilloscopes from plastic scintillators positioned within the neutron path [23]. The saturated peak at time t=0 is a result of relativistic signal and, therefore, arises from the initial x-ray flash from bremsstrahlung emission.…”

Section: Resultsmentioning

confidence: 99%

Evaluating laser-driven Bremsstrahlung radiation sources for imaging and analysis of nuclear waste packages

Jones

Brenner

Stitt

et al. 2016

Journal of Hazardous Materials

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A small scale sample nuclear waste package, consisting of a 28mm diameter uranium penny encased in grout, was imaged by absorption contrast radiography using a single pulse exposure from an x-ray source driven by a highpower laser. The Vulcan laser was used to deliver a focused pulse of photons to a tantalum foil, in order to generate a bright burst of highly penetrating x-rays (with energy >500keV), with a source size of <0.5mm. BAS-TR and BAS-SR image plates were used for image capture, alongside a newly developed Thalium doped Caesium Iodide scintillator-based detector coupled to CCD chips. The uranium penny was clearly resolved to sub-mm accuracy over a 30cm 2 scan area from a single shot acquisition. In addition, neutron generation was demonstrated in situ with the x-ray beam, with a single shot, thus demonstrating the potential for multi-modal criticality testing of waste materials. This feasibility study successfully demonstrated non-destructive radiography of encapsulated, high density, nuclear material. With recent developments of high-power laser systems, to 10Hz operation, a laser-driven multi-modal beamline for waste monitoring applications is envisioned.

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“…To check that this gold film did not induce luminescence either by plasmon excitation or by transition radiation, we deposited it on a bare sapphire substrate. The luminescence detection system was then tested using a commercial fast scintillator, BC-422Q 18,19 , in which the excited states created by the ionizing radiation are partially quenched by the addition of benzophenone (5%). It has a nominal 0.7 ns time constant 20 .…”

Section: Electron-induced Compared To Uv-induced Luminescencementioning

confidence: 99%

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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Calibration of time of flight detectors using laser-driven neutron source

Cited by 25 publications

References 31 publications

Beamed neutron emission driven by laser accelerated light ions

Beamed neutron emission driven by laser accelerated light ions

Evaluating laser-driven Bremsstrahlung radiation sources for imaging and analysis of nuclear waste packages

Time-resolved cathodoluminescence of DNA triggered by picosecond electron bunches

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