Femtosecond time-resolved MeV electron diffraction

• Published in: New journal of physics Vol. 17; no. 6; pp. 63004 - 63009
• Main Authors: Zhu, Pengfei, Zhu, Y, Hidaka, Y, Wu, L, Cao, J, Berger, H, Geck, J, Kraus, R, Pjerov, S, Shen, Y, Tobey, R I, Hill, J P, Wang, X J
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 02.06.2015
• Subjects: 61.05.J; Aluminum; ATOMIC AND MOLECULAR PHYSICS; Coherence length; coherent length; Diffraction patterns; Elastic scattering; Electron beams; Electron diffraction; Electrons; Emittance; high-brightness electron beam; Laser beams; numbers:41.75.Fr; Physics; Scattering cross sections; Single crystals; Superlattices; Temporal resolution; Timing jitter; ultrafast electron diffraction; ultrafast electron imaging; Vibration
• ISSN: 1367-2630; 1367-2630
• DOI: 10.1088/1367-2630/17/6/063004

We report the experimental demonstration of femtosecond electron diffraction using high-brightness MeV electron beams. High-quality, single-shot electron diffraction patterns for both polycrystalline aluminum and single-crystal 1T-TaS2 are obtained utilizing a 5 fC (∼3 × 104 electrons) pulse of electrons at 2.8 MeV. The high quality of the electron diffraction patterns confirms that electron beam has a normalized emittance of ∼50 nm rad. The transverse and longitudinal coherence length is ∼11 and ∼2.5 nm, respectively. The timing jitter between the pump laser and probe electron beam was found to be ∼100 fs (rms). The temporal resolution is demonstrated by observing the evolution of Bragg and superlattice peaks of 1T-TaS2 following an 800 nm optical pump and was found to be 130 fs. Our results demonstrate the advantages of MeV electrons, including large elastic differential scattering cross-section and access to high-order reflections, and the feasibility of ultimately realizing below 10 fs time-resolved electron diffraction.