By Center for Functional Nanomaterials Brookhaven
For the past three decades, the Instrumentation Department has been at the forefront of generating electron beams with high brightness for collider and photon source applications. Our surveys of materials have led to the worldwide adoption of copper (Cu) and magnesium (Mg) for high-peak-brightness electron beams. We were the first to investigate the use of ultrashort laser pulses and associated field and plasmon processes, leading to enhanced photoemission. Our patented cathode preparation techniques resulted in a 100- to 10,000-fold improvement in quantum yield. These efforts have also led to record-setting cathode lifetimes, applications beyond high-brightness electron injectors, and a fundamental understanding of photocathode material properties and fabrication. Our Capabilities - Survey and selection of a variety of materials—including metals, semiconductors, bulk insulators, and topological insulators—as electron sources customized for different applications - Design, construction, testing, and commissioning of ultrahigh-vacuum (UHV) and extreme-high-vacuum systems with thermal and electrical feedthroughs for cathode fabrication and transport - Design, construction, testing, and commissioning of high-purity cryogenic systems - Deposition of thin films and characterization of material composition and crystalline properties using x-ray sources at synchrotron beamlines - Growth and optimization of bialkali antimonide photocathodes for applications requiring low-emittance electron beams (e.g., ultrafast electron diffraction, energy recovery linacs, free-electron lasers) via a custom-designed mobile system for the simultaneous fabrication and x-ray characterization of these materials under vacuum—the only such system in the world - Characterization of the surface properties (e.g., smoothness, composition) of materials via atomic force microscopy and scanning electron microscopy - Preparation of substrates and metal surfaces in situ (heating and laser cleaning) and ex situ (polishing and ultrasonic cleaning) - Development, use, and maintenance of photon sources: continuous-wave and pulsed-light sources and laser systems with wavelengths spanning from 1 to 0.2 μm, pulse durations ranging from microsecond to femtosecond, and repetition rates extending from continuous to a few tens of Hz
