Nondestructive detection of hidden chemical compounds with laser Compton-scattering gamma rays

Abstract

A nondestructive assay method for measuring a shielded chemical compound has been proposed. The chemical compound is measured by using a nuclear resonance fluorescence (NRF) measurement technique with an energy tunable laser Compton-scattering (LCS) gamma-ray source. This method has an advantage that hidden materials can be detected through heavy shields such as iron plates of a thickness of several centimeters. A detection of a chemical compound of melamine, C(3)H(6)N(6), shielded by 15-mm-thick iron and 4-mm-thick lead plates is demonstrated. The NRF gamma-rays of (12)C and (14)N of the melamine are measured by using the LCS gamma-rays of the energies of up to 5.0 MeV. The observed ratio ((12)C/(14)N)(exp)=0.39+/-0.12 is consistent with (C/N)(melamine)=0.5.

Femtosecond pulse trains of polychromatic inverse Compton γ-rays from designer electron beams produced by laser-plasma acceleration in plasma channels

“…This accordion effect [5] causes periodic self-injection of ambient electrons and their subsequent acceleration without quality degradation, while the negative chirp of the driver reduces the pollution of electron spectra by a low-energy background. The first-principles numerical simulations show that, due to the low phase space volume, clear separation of spectral components in energy, and a minimal amount of noise, the comblike electron beams can drive compact, tunable, multi-color ICS γ-ray sources that can find applications in nuclear photonics and radiography [19][20][21]. Natural mutual synchronization of fs-length electron bunches and γ-ray flashes may be an asset to pump-probe experiments and laboratory modeling of single-event effects.…”

“…These comb-like beams may find a unique application as drivers of all-optical γ-ray sources [6][7][8][9][10][11] based on the inverse Compton scattering (ICS) mechanism [12][13][14]. The production of bright, psduration ICS γ-rays has been earlier demonstrated with head-on collisions of intense laser pulses and electron beams from conventional accelerators [15][16][17][18][19][20][21][22]. These γ-rays, which are well collimated, quasi-monochromatic (QM), and have a high degree of polarization, are attractive as electron beam diagnostics [15].…”

“…These γ-rays, which are well collimated, quasi-monochromatic (QM), and have a high degree of polarization, are attractive as electron beam diagnostics [15]. ICS γ-rays are also employed in the generation of polarized positrons from dense targets [17] and to demonstrate nuclear fluorescence [19][20][21]. Nuclear photonics applications benefit from the portability and unprecedented degree of control over the radiation spectrum afforded by an all-optical γ-ray source.…”

Performance of the LaBr<inf>3</inf>(Ce) scintillator for nuclear resonance fluorescence experiment

“…The expected total photon flux is 1.0×10 13 photons/s and a peak spectral density is 7.0×10 9 photons/s keV for an assumed facility with 350 MeV ERL and Yb-doped fiber laser. [4] Manuscript The required performances of the detector used in the NRF measurement are high energy resolution, high full energy efficiency, and high counting rate. Therefore most of the NRF experiments have been carried out by using high purity germanium (HP-Ge) detectors with large volumes.…”

Optically controlled laser–plasma electron accelerator for compact gamma-ray sources

“…In addition, weak focusing of the trailing component of the stack induces periodic injection, generating, in a single shot, a train of bunches with controllable energy spacing and femtosecond synchronization. These designer e-beams, inaccessible to conventional acceleration methods, generate, via TS, gigawatt γ-ray pulses (or multi-color pulse trains) with the mean energy in the range of interest for nuclear photonics (4-16 MeV), containing over 10 6 photons within a microsteradian-scale observation cone.The production of multi-picosecond TS γ-ray pulses has been earlier demonstrated using e-beams from conventional accelerators [12][13][14][15][16][17][18][19][20][21]. These pulses have a high degree of polarization, and are thus attractive as e-beam diagnostics [12,13].…”