Photocathode Optimization for a Dynamic Transmission Electron Microscope: Final Report
The Dynamic Transmission Electron Microscope (DTEM) team at Harvey Mudd College has been sponsored by LLNL to design and build a test setup for optimizing the performance of the DTEM's electron source. Unlike a traditional TEM, the DTEM achieves much faster exposure times by using photoemission from a photocathode to produce electrons for imaging. The DTEM team's work is motivated by the need to improve the coherence and current density of the electron cloud produced by the electron gun in order to increase the image resolution and contrast achievable by DTEM. The photoemission test setup is nearly complete and the team will soon complete baseline tests of electron gun performance. The photoemission laser and high voltage power supply have been repaired; the optics path for relaying the laser to the photocathode has been finalized, assembled, and aligned; the internal setup of the vacuum chamber has been finalized and mostly implemented; and system control, synchronization, and data acquisition has been implemented in LabVIEW. Immediate future work includes determining a consistent alignment procedure to place the laser waist on the photocathode, and taking baseline performance measurements of the tantalum photocathode. Future research will examine the performance of the electron gun as a function of the photoemission laser profile, the photocathode material, and the geometry and voltages of the accelerating and focusing components in the electron gun. This report presents the team's progress and outlines the work that remains.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 1022922
- Report Number(s):
- LLNL-SR-492012
- Country of Publication:
- United States
- Language:
- English
Similar Records
Quarterly progress report for Q1 FY06 for Complex Transient Events in Materials Studied Using Ultrafast Electron Probes and Terascale Simulation (FWP SCW0289)
Next Generation Robust Polarization Photocathodes for EIC
DEVELOPMENT OF A 300 KV DC HIGH VOLTAGE PHOTOGUN AND BEAM BASED STUDIES OF ALKALI NTIMONIDE PHOTOCATHODES
Technical Report
·
Mon Dec 26 23:00:00 EST 2005
·
OSTI ID:896008
Next Generation Robust Polarization Photocathodes for EIC
Technical Report
·
Thu Jan 31 23:00:00 EST 2019
·
OSTI ID:1496836
DEVELOPMENT OF A 300 KV DC HIGH VOLTAGE PHOTOGUN AND BEAM BASED STUDIES OF ALKALI NTIMONIDE PHOTOCATHODES
Thesis/Dissertation
·
Fri Nov 30 23:00:00 EST 2018
·
OSTI ID:1924638
Related Subjects
42 ENGINEERING
47 OTHER INSTRUMENTATION
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALIGNMENT
CLOUDS
CURRENT DENSITY
DATA ACQUISITION
ELECTRON GUNS
ELECTRON MICROSCOPES
ELECTRON SOURCES
ELECTRONS
FOCUSING
GEOMETRY
LASERS
OPTICS
OPTIMIZATION
PHOTOCATHODES
PHOTOEMISSION
RESOLUTION
SYNCHRONIZATION
TANTALUM
47 OTHER INSTRUMENTATION
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALIGNMENT
CLOUDS
CURRENT DENSITY
DATA ACQUISITION
ELECTRON GUNS
ELECTRON MICROSCOPES
ELECTRON SOURCES
ELECTRONS
FOCUSING
GEOMETRY
LASERS
OPTICS
OPTIMIZATION
PHOTOCATHODES
PHOTOEMISSION
RESOLUTION
SYNCHRONIZATION
TANTALUM