US 6,333,966 B1 · Laser accelerator femtosecond X-ray source

Abstract

A technology for generating femtosecond time regime x-ray pulses for application to the study of the structure and reactions of biological molecules, photosynthesis reactions, semiconductor device fabrication, structural determination and dynamic performance, and other chemical, biological and physical processes taking place on sub-picosecond time scales. Electrons are accelerated to hundreds of keV to tens of MeV energies using high energy, femtoseconds duration laser pulses, and are then converted to x-rays by one of several physical processes. Because the laser accelerated electrons have the pulse width of the laser driver, extremely short (less than 100 femtoseconds) x-ray pulses can be produced from these electrons. The x-ray energy and emittance can be controlled by electron beam production and beam transport techniques and/or collimators or x-ray optical systems. The use of laser acceleration and novel electron to x-ray conversion processes should result in significantly lower costs than current synchrotron-based x-ray sources, and lead to widespread introduction of this tool into commercial biological and medical x-ray and materials structure research laboratory environments. In addition, multi-beam sources of electrons from conventional electron devices, such as field emission diodes and thermionic emission devices, can be used in conjuction with novel x-ray beam combining techniques to produce a long pulse, high flux collimated x-ray beam suitable for use in biological x-ray crystallography studies.

Claims14

Dependent claims

A laser electron accelerator driven sub-picosecond time scale x-ray source device with enhanced output produced by coherent x-ray production and a multi-beam combining optics system, for application to structure and reaction studies of biological molecules, high resolution medical imaging, and structure and behavior studies of semiconductor devices, comprising;

multi-Joule energy input laser means to provide initial high energy laser pulse which can be subsequently compressed in pulse duration to achieve femtoseconds time ranges;
laser pulse compression means to achieve femtoseconds range output pulses from said input laser means;
electron or plasma production means to provide a source of electrons for a laser acceleration process using said femtoseconds range output pulses;
electron acceleration means using said laser output pulses chromagnetic forces applied to said source of electrons to cause phase bunching at intervals selectable by the wavelength of said input laser means and accelerating them to multi-MeV energy levels;
coherent Bremsstrahlung and line radiation x-ray conversion means using the spatial and temporal periodicity of said electron phase bunching and an electron beam target periodic atomic structure to convert said laser accelerated electrons to x-ray photons suitable for application requirements, and;
x-ray optics components means to transport, combine, filter and focus said x-ray photons to produce a desired x-ray beam photon flux and divergence angle at a location of an application sample material under study.

3 more elements

A long pulse (nanoseconds regime) electron emitting array driven x-ray source device for application to structure and reaction studies of biological molecules, high resolution medical imaging, and semiconductor processing, comprising;

electron emitting array means to produce kiloampere or greater electron beam pulses of energies from the K-edge of beryllium up to several hundred keV, said electron beam pulses produced by a discharge from a cylindrical capacitive storage device which discharges in transmission line fashion to produce a rectangular high voltage pulse of up to said several hundred keV which is applied to said electron emitting array;
electron beam optics components means to transport, filter and focus accelerated electrons;
x-ray conversion means to convert said electron beam pulses into x-rays, including low to high Z Bremsstrahlung foils backed by low Z electron stopping foils, which produce Bremsstrahlung and line x-ray radiation output and;
x-ray optics components means to transport, combine, filter and focus said x-ray photons to produce a desired x-ray beam photon flux and divergence angle at a location of an application sample material.

1 more element

Dependencies are inferred from the claim text.

Laser accelerator femtosecond X-ray source

Life of this patent

Laser accelerator femtosecond X-ray source

Life of this patent

Abstract

Claims14