INEXPENSIVE ELECTRON BEAM OPTICS FOR ULTRAFAST ELECTRON MICROSCOPY
Unlike traditional Transmission Electron Microscopes (TEM) Ultrafast Electron Diffraction (UED) and Microscopy (UEM) operate at higher electron energies to preserve the high quality electron beam required for unprecedented temporal and spatial resolution. This however forces stringent requirements on electron-optical components. In particular a set of high field (2 Tesla) solenoids acting as condenser, objective and projection lens are needed. While superconducting solenoids are expensive and require cryogenics, normal conducting solenoids are incredibly bulky, weighing about 2 tons each. At present there is no compact UEM optics available to enable a marketable machine. The uniqueness of the Euclid’s proposal is its utilization of a flux concentrator (FC), a pulsed technology adopted for the design of the ILC positron target collection solenoid. Duty cycle reduction allows for a significant reduction in the size of the magnet. Pulsed operation allows a high peak magnetic field (2 Tesla) at a reasonable heat load, which can be managed by conventional cooling. In this project, we have designed and fabricated to a few FC lenses. By incorporating the simulated FC field map into their MeV UEM beam optics model, simulations showed that the best resolution of 2.3Å can be achieved with Bz = 2T and a relative beam energy spread of ~1e-5 when the sample is positioned approximately 3cm upstream of the center of the objective lens. Alternatively, a resolution of 7.0Å can be achieved when the energy spread is ~1e-4. The FC lens was ultimately tested at the BNL ATF UED beamline, where it successfully demonstrated its function as a highly stable lens for the MeV sub-picosecond beam. In conclusion, this project has validated the use of FC-based lenses as a viable technical approach for constructing a table-top MeV UEM beamline.
- Research Organization:
- Euclid Techlabs LLC
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Contributing Organization:
- Brookhaven National Laboratory
- DOE Contract Number:
- SC0018622
- OSTI ID:
- 1985699
- Type / Phase:
- SBIR (Phase II)
- Report Number(s):
- DOE-EUCLID-18622
- Country of Publication:
- United States
- Language:
- English
Similar Records
A compact tunable quadrupole lens for brighter and sharper ultra-fast electron diffraction imaging
Pulse compressor with aberration correction