Nuclear photonics

Abstract

With the planned new γ-beam facilities like MEGa-ray at LLNL (USA) or ELI-NP at Bucharest (Romania) with 10 13 γ/s and a band width of ΔE γ /E γ ≈ 10 −3 , a new era of γ beams with energies up to 20 MeV comes into operation, compared to the present world-leading HIγS facility at Duke University (USA) with 10 8 γ/s and ΔE γ /E γ ≈ 3 · 10 −2 . In the long run even a seeded quantum FEL for γ beams may become possible, with much higher brilliance and spectral flux. At the same time new exciting possibilities open up for focused γ beams. Here we describe a new experiment at the γ beam of the ILL reactor (Grenoble, France), where we observed for the first time that the index of refraction for γ beams is determined by virtual pair creation. Using a combination of refractive and reflective optics, efficient monochromators for γ beams are being developed. Thus, we have to optimize the total system: the γ-beam facility, the γ-beam optics and γ detectors. We can trade γ intensity for band width, going down to ΔE γ /E γ ≈ 10 −6 and address individual nuclear levels. The term "nuclear photonics" stresses the importance of nuclear applications. We can address with γ-beams individual nuclear isotopes and not just elements like with X-ray beams. Compared to X rays, γ beams can penetrate much deeper into big samples like radioactive waste barrels, motors or batteries. We can perform tomography and microscopy studies by focusing down to μm resolution using Nuclear Resonance Fluorescence (NRF) for detection with eV resolution and high spatial resolution at the same time. We discuss the dominating M1 and E1 excitations like the scissors mode, two-phonon quadrupole octupole excitations, pygmy dipole excitations or giant dipole excitations under the new facet of applications. We find many new applications in biomedicine, green energy, radioactive waste management or homeland security. Also more brilliant secondary beams of neutrons and positrons can be produced.

Refractive Index of Silicon atγRay Energies

“…We will develop a whole new γ optics tool box: γ lenses for focusing, gold prisms for deflection, short γ wave guides from gold with total internal reflection. With a combination of refractive and diffractive γ optics, we can realize very efficient γ monochromatisation down to a band width of 10 −6 , allowing to address individual nuclear levels up to the neutron binding energy [17]. With the upcoming, 10 7 times more brilliant and intense γ beams of MEGa-Ray (Livermoore, USA, 2013) [18] and ELI-NP (Bucharest, Romania, 2015) [19], compared to the present worldwide best γ facility HIγS (Duke University, USA), a broad field of new applications with nuclear resonance excitation (radioactive waste management, imaging of 7 Li in batteries for green energy, production of about 50 new medical radioisotopes with high specific activity for diagnostics and therapy [20] etc..) opens up in nuclear photonics [17].…”

Collimated ultrabright gamma rays from a petawatt-laser-driven QED wire wiggler (Conference Presentation)

“…In our case with the peak intensity around 10 23 Wcm −2 and the wire width below λ 0 , the electrons on the wire surface are quickly stripped and therefore, the static field strength or |F wiggler y | depends strongly upon the wire charge density and weakly upon the laser intensity, as observed in our simulations and Eq. (2). When the wire parameter is fixed and the laser power P 0 is adopted within 0.5 to 5PW, one can roughly take |F wiggler y | as a value about 50 according to our simulations and then χ ≃ 0.00037a 0 .…”

“…Bright γ−rays with energy above MeV are highly demanded in broad applications ranging from laboratory astrophysics [1], emerging nuclear photonics [2,3], to radiotherapy [4,5].…”

Efficient bright γ-ray vortex emission from a laser-illuminated light-fan-in-channel target

“…Bright X/γ-ray sources have various applications in the laboratory astrophysics, nuclear photonics, ultra-highdensity matter radiography, high-flux positron generation, and nuclear medical imaging [1][2][3][4][5][6] . Hard X/γ-rays are conventionally produced by large synchrotron facilities with peak brilliance in the range of ∼ 10 19 -10 24 photons•s -1 •mm -2 •mrad -2 per 0.1% bandwidth and photon energy ranging from several kiloelectronvolts (keV) to megaelectronvolts (MeV).…”