Prof Peter Norreys FInstP;: Publications

Using high-power lasers for detection of elastic photon-photon scattering

(2005)

Authors:

E Lundstrom, G Brodin, J Lundin, M Marklund, R Bingham, J Collier, JT Mendonca, P Norreys

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(2005) 110

Authors:

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Characterization of a picosecond laser generated 4.5 keV Ti K -alpha source for pulsed radiography

Review of Scientific Instruments 76:7 (2005)

Authors:

JA King, K Akli, RA Snavely, B Zhang, MH Key, CD Chen, M Chen, SP Hatchett, JA Koch, AJ MacKinnon, PK Patel, T Phillips, RPJ Town, RR Freeman, M Borghesi, L Romagnani, M Zepf, T Cowan, R Stephens, KL Lancaster, CD Murphy, P Norreys, C Stoeckl

Abstract:

K�� radiation generated by interaction of an ultrashort (1 ps) laser with thin (25 ��m) Ti foils at high intensity (2�� 1016 W cm2) is analyzed using data from a spherical Bragg crystal imager and a single hit charge-coupled device spectrometer together with Monte Carlo simulations of K�� brightness. Laser to K�� and electron conversion efficiencies have been determined. We have also measured an effective crystal reflectivity of 3.75��2%. Comparison of imager data with data from the relatively broadband single hit spectrometer has revealed a reduction in crystal collection efficiency for high K�� yield. This is attributed to a shift in the K -shell spectrum due to Ti ionization. ? 2005 American Institute of Physics.

Beam instabilities in laser-plasma interaction: Relevance to preferential ion heating

Physical Review Letters 94:24 (2005)

Authors:

JT Mendon?a, P Norreys, R Bingham, JR Davies

Abstract:

We propose a new mechanism for anomalous ion heating in ultraintense laser plasmas. This mechanism is based on the excitation of an electron two-stream instability that is driven by the fast electron beam that resonantly decays into ion-acoustic waves. These low frequency waves are then strongly damped by the ion collisions in the dense plasma. The model gives a simple explanation for the preferential heating of the bulk ion population observed in recent laser experiments in the petawatt regime. In particular, this work provides an explanation for the different energy loss in the Au and CD plasmas, in cone-guided fast ignition experiments. ? 2005 The American Physical Society.

Broad energy spectrum of laser-accelerated protons for spallation-related physics

Physical Review Special Topics - Accelerators and Beams 8 (2005) 1-4

Authors:

P McKenna, KWD Ledingham, S Shimizu, JM Yang, L Robson, T McCanny, J Galy, J Magill, RJ Clarke, D Neely, PA Norreys, RP Singhal, K Krushelnick, MS Wei

Abstract:

A beam of MeV protons, accelerated by ultraintense laser-pulse interactions with a thin target foil, is used to investigate nuclear reactions of interest for spallation physics. The laser-generated proton beam is shown (protons were measured) to have a broad energy distribution, which closely resembles the expected energy spectrum of evaporative protons (below 50 MeV) produced in GeV-proton-induced spallation reactions. The protons are used to quantify the distribution of residual radioisotopes produced in a representative spallation target (Pb), and the results are compared with calculated predictions based on spectra modeled with nuclear Monte Carlo codes. Laser-plasma particle accelerators are shown to provide data relevant to the design and development of accelerator driven systems. ? 2005 The American Physical Society.

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