Demonstration of the synchrotron-type spectrum of laser-produced Betatron radiation

Betatron x-ray radiation in laser–plasma accelerators is produced when electrons are accelerated and wiggled in the laser-wakefield cavity. This femtosecond source, producing intense x-ray beams in the multi-kiloelectronvolt (keV) range, has been observed at different interaction regimes using a high-power laser from 10 to 100 TW. However, none of the spectral measurements carried out were at sufficient resolution, bandwidth and signal-to-noise ratio to precisely determine the shape of spectra with a single laser shot in order to avoid shot-to-shot fluctuations. In this paper, the Betatron radiation produced using a 80 TW laser is characterized by using a single photon counting method. We measure in a single shot spectra from 8 to 21 keV with a resolution better than 350 eV. The results obtained are in excellent agreement with theoretical predictions and demonstrate the synchrotron-type nature of this radiation mechanism. The critical energy is found to be Ec=5.6±1 keV for our experimental conditions. In addition, the features of the source at this energy range open up novel opportunities for applications in time-resolved x-ray science.

[1]  Zulfikar Najmudin,et al.  Bright spatially coherent synchrotron X-rays from a table-top source , 2010 .

[2]  Andrew G. Glen,et al.  APPL , 2001 .

[3]  Alexander Pukhov,et al.  X-ray generation in an ion channel , 2003 .

[4]  Dong Eon Kim,et al.  Demonstration of the ultrafast nature of laser produced betatron radiation , 2007 .

[5]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[6]  S. Shiraishi,et al.  Spectroscopy of betatron radiation emitted from laser-produced wakefield accelerated electrons. , 2010, The Review of scientific instruments.

[7]  B. Remington,et al.  Calibration and characterization of single photon counting cameras for short-pulse laser experiments. , 2008, The Review of scientific instruments.

[8]  Z. Najmudin,et al.  Comparative study of betatron radiation from laser-wakefield and direct-laser accelerated bunches of relativistic electrons , 2009, Optics + Optoelectronics.

[9]  R. Fonseca,et al.  Direct observation of betatron oscillations in a laser-plasma electron accelerator , 2008 .

[10]  Antoine Rousse,et al.  Betatron oscillations of electrons accelerated in laser wakefields characterized by spectral x-ray analysis. , 2008, Physical review. E, Statistical, nonlinear, and soft matter physics.

[11]  Antoine Rousse,et al.  Production of a keV x-ray beam from synchrotron radiation in relativistic laser-plasma interaction. , 2004, Physical review letters.

[12]  A. Pukhov,et al.  X-ray generation in strongly nonlinear plasma waves. , 2004, Physical review letters.

[13]  J. Meyer-ter-Vehn,et al.  Laser wake field acceleration: the highly non-linear broken-wave regime , 2002 .

[14]  E. Esarey,et al.  Synchrotron radiation from electron beams in plasma-focusing channels. , 2002, Physical review. E, Statistical, nonlinear, and soft matter physics.

[15]  D. Neely,et al.  Characterization of neutral density profile in a wide range of pressure of cylindrical pulsed gas jets , 2000 .

[16]  A. Alexandrov,et al.  Laser beam wavefront correction for ultra high intensities with the 200 TW laser system at the advanced laser light source. , 2008, Optics express.

[17]  D. Jaroszynski,et al.  Harnessing Relativistic Plasma Waves As Novel Radiation Sources from Terahertz to X-rays and Beyond , 2009 .

[18]  S R Nagel,et al.  Observation of synchrotron radiation from electrons accelerated in a petawatt-laser-generated plasma cavity. , 2008, Physical review letters.

[19]  Y. Glinec,et al.  A laser–plasma accelerator producing monoenergetic electron beams , 2004, Nature.

[20]  J. Cary,et al.  High-quality electron beams from a laser wakefield accelerator using plasma-channel guiding , 2004, Nature.

[21]  A. Rousse,et al.  Imaging Electron Trajectories in Laser Wakefield Cavity using betatron X-Ray Radiation , 2006, 2007 Conference on Lasers and Electro-Optics (CLEO).

[22]  S. Kneip,et al.  Controlling the spectrum of x-rays generated in a laser-plasma accelerator by tailoring the laser wavefront , 2009, 0909.3440.

[23]  M. Mostafavi,et al.  Absolute calibration for a broad range single shot electron spectrometer , 2006 .

[24]  D. Descamps,et al.  Broadband, high dynamics and high resolution charge coupled device-based spectrometer in dynamic mode for multi-keV repetitive x-ray sources. , 2009, The Review of scientific instruments.

[25]  A. E. Dangor,et al.  Monoenergetic beams of relativistic electrons from intense laser–plasma interactions , 2004, Nature.

[26]  T. Tajima,et al.  Laser Electron Accelerator , 1979 .

[27]  Alexander Thomas,et al.  Scalings for radiation from plasma bubbles , 2010 .