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2012
Book Article
Title
Gateable micro channel plate detector for extreme ultraviolet radiation with high temporal resolution
Abstract
Research in ultrafast nanoscale phenomena requires high spatial and temporal resolution detectors. Optical imaging microscopes achieve high time resolution but low spatial resolution and scanning microscopes vice versa. Extreme ultraviolet imaging microscopy closes this gap but demands a suited two dimensional detector with high sensitivity and fast gating ability.
In this work a new BURLE’s 2-micron pore microchannel plate photoelectron multiplier together with a phosphor screen is used as a detector and further optimized with respect to its time resolution. The operation voltage of the electron-multiplier is pulsed for 1.25 ns. Only during that time the detector is highly sensitive to extreme ultraviolet light. A custom built impedance transformer delivers high currents into the plates’ capacitance. This leads to a short charging time and ensures a narrow temporal sensitivity window.
The following attributes of the detector system are analyzed:
• Temporal behavior is measured by femtosecond illumination with high harmonics generation radiation at different relative delays. The sensitivity curve has a width of 2 ns. Electronic timing jitter is below 150 ps.
• Spatial resolution is determined by mapping the shadow of a sharp edge on the detector. The smearing gives information about the modulation transfer function. The resolution limit according to the Rayleigh criterion is at 12 lp/mm or a minimum resolvable pitch of 80 μm.
In summary the detector provides a spatial resolution down to 80 nm and a time resolution shorter than 2 ns using a discharge produced plasma EUV source and a zone plate based microscope with a magnification of ~1000x. This is a highly interesting combination and will help to investigate a variety of short time processes in nanoscience [1].
In this work a new BURLE’s 2-micron pore microchannel plate photoelectron multiplier together with a phosphor screen is used as a detector and further optimized with respect to its time resolution. The operation voltage of the electron-multiplier is pulsed for 1.25 ns. Only during that time the detector is highly sensitive to extreme ultraviolet light. A custom built impedance transformer delivers high currents into the plates’ capacitance. This leads to a short charging time and ensures a narrow temporal sensitivity window.
The following attributes of the detector system are analyzed:
• Temporal behavior is measured by femtosecond illumination with high harmonics generation radiation at different relative delays. The sensitivity curve has a width of 2 ns. Electronic timing jitter is below 150 ps.
• Spatial resolution is determined by mapping the shadow of a sharp edge on the detector. The smearing gives information about the modulation transfer function. The resolution limit according to the Rayleigh criterion is at 12 lp/mm or a minimum resolvable pitch of 80 μm.
In summary the detector provides a spatial resolution down to 80 nm and a time resolution shorter than 2 ns using a discharge produced plasma EUV source and a zone plate based microscope with a magnification of ~1000x. This is a highly interesting combination and will help to investigate a variety of short time processes in nanoscience [1].