US 9,853,412 B2 · Radiation source

Abstract

Passage through LINACs of electron bunches in their acceleration phase is coordinated with passage through the LINACs of electron bunches in their deceleration phase. Each successive pair of electron bunches are spaced in time by a respective bunch spacing, in accordance with a repeating electron bunch sequence. The electron source provides clearing gaps in the electron bunch sequence to allow clearing of ions at the undulator. The electron source provides the clearing gaps in accordance with a clearing gap sequence such that, for each of the plurality of energy recovery LINACS, and for substantially all of the clearing gaps: for each passage of the clearing gap through the LINAC in an acceleration phase or deceleration phase the clearing gap is coordinated with a further one of the clearing gaps passing through the LINAC in a deceleration phase or acceleration phase thereby to maintain energy recovery operation of the LINAC.

Claims19

Dependent claims

A method of producing extreme ultraviolet (EUV) radiation using a free electron laser (FEL), the method comprising:

directing a drive laser beam onto a cathode to generate electron bunches;
passing the electron bunches to a linear accelerator (LINAC) to accelerate the electron bunches;
passing the electron bunches along an electron bunch path through an undulator configured to generate EUV radiation;
and
removing positively charged ions from the electron bunch path by applying a variation of charge or emittance of the electron bunches within a pre-determined range;
wherein the pre-determined range of charge or emittance variation is selected to restrict variation of accelerating gradients in the LINAC.

3 more elements

Dependencies are inferred from the claim text.

Radiation source

Life of this patent

Radiation source

Life of this patent

Abstract

Claims19