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TY - CONF AU - Denham, P.E. ED - Yamazaki, Yoshishige ED - Raubenheimer, Tor ED - McCausey, Amy ED - Schaa, Volker RW TI - Progress in Time-Resolved MeV Transmission Electron Microscopy at UCLA J2 - Proc. of NAPAC2019, Lansing, MI, USA, 01-06 September 2019 CY - Lansing, MI, USA T2 - North American Particle Accelerator Conference T3 - 4 LA - english AB - We describe here two new enhancements developed for the time-resolved microscope at the UCLA PEGASUS Lab based on the use of a radiofrequency photoinjector as an ultrafast electron source and permanent magnet quadrupoles as electron lenses. The first enhancement is a flexible optical column design including hybrid-style stronger focusing quadrupoles, yielding a 60% magnification increase, and a collimator to improve imaging contrast. This new optical system will have the ability to switch between real-space imaging and diffraction pattern imaging with variable magnification. The second enhancement is a high-frequency (X-band) cavity downstream from the (S-band) photoinjector to reduce the beam energy spread. These enhancements are crucial for improving contrast and image quality. In addition, a pulse-wire alignment method to fiducialize the quadrupole positions to better than 20-um precision is used to reduce the aberrations induced by misalignment and achieve spatial resolution at the 20 nm-level. PB - JACoW Publishing CP - Geneva, Switzerland SP - 243 EP - 246 KW - electron KW - quadrupole KW - cavity KW - alignment KW - detector DA - 2019/10 PY - 2019 SN - 2673-7000 SN - 978-3-95450-223-3 DO - doi:10.18429/JACoW-NAPAC2019-MOPLO04 UR - http://jacow.org/napac2019/papers/moplo04.pdf ER -