Neutral Helium Microscope Probe Direction Filter
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Solution Overview
Problem
Neutral helium microscopes face a challenge in achieving high signal-to-noise ratio (S/N) due to background helium atoms generated by the beam, which decreases the accuracy of measurements and requires longer times for investigation of larger sample portions.
Innovation Solution
A probe with a direction filter and neutral particle detector is used, featuring a micro-channel plate with elongated channels that allow passage only from the target location to the filter area, effectively reducing background noise by preventing scattered particles with randomized directions from interfering with the signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a beam of neutral helium is used for matter-wave microscopy, then chemical inertness and non-damage to fragile samples are achieved, but background helium atoms are continuously generated by the beam which decreases the signal-to-noise ratio
Solution Approach 1:
The patent extracts and removes background helium atoms from the detection path by introducing a cold atom cloud that selectively absorbs background atoms through resonant scattering, while allowing signal atoms to pass through to the detector
Solution Approach 2:
A cold atom cloud serves as an intermediary medium between the beam and detector, selectively interacting with background helium atoms through resonant scattering while being transparent to signal atoms, thereby mediating the separation of signal from background noise
2Measurement precision
If continuous evacuation of the vacuum chamber is performed, then background helium removal is attempted, but background helium atoms are continuously generated by the beam making evacuation ineffective
Solution Approach 1:
The patent converts the harmful continuous background generation into a beneficial effect by using the beam-generated helium atoms as the very medium for resonant scattering in the cold atom cloud, which selectively removes background atoms while preserving signal atoms
Solution Approach 2:
The patent changes the temperature parameter by introducing a cold atom cloud at temperatures near absolute zero, creating a dense cloud of ultra-cold atoms that exhibit resonant scattering behavior selective to background helium atoms, thereby enabling differential removal of background versus signal atoms
3Productivity
If measurement time is reduced for larger sample portions, then productivity increases, but signal-to-noise ratio decreases requiring longer measurement times
Solution Approach 1:
The patent extracts background noise from the measurement signal by using resonant scattering in a cold atom cloud to selectively remove background helium atoms, thereby improving signal-to-noise ratio and enabling faster measurements of larger sample portions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly enhances the signal-to-noise ratio by isolating signal particles from background noise, allowing for shorter measurement times and larger sample investigation, while also enabling the probe to be scaled down for improved spatial resolution and reduced background scattering.
Implementation Method 1
The direction filter is adapted to allow passage through the direction filter for particles travelling in a direction from the target location to the filter area. The direction filter is further adapted to impede passage through the direction filter for particles traveling in a direction that is different from a direction from the target location to the filter area.
Implementation Method 2
The direction filter comprises a plate-like structure having a first face and a second face. The filter area is located on the first face and the plate-like structure comprises a two-dimensional array of elongated channels leading from the first face to the second face for allowing passage through the plate-like structure for particles travelling in a direction from the target location to the filter area.
Implementation Method 3
The probe further comprises a neutral particle detector for detecting particles that has passed through the direction filter.
Data Source
Figure 1~2
Figure 3A~3B
Figure 3C~3F
AI summary
A probe (28), as used in a scanning neutral helium microscope, for detecting neutral particles originating from a beam (20) of neutral particles directed at a target location (21) of a sample (22) and subsequently scattered at the target location (21) is disclosed. The probe (28) has a direction filter (32), such a microplate shutter having a plurality of microchannels (58), that is adapted to allow passage through the direction filter (32) for particles travelling in a direction from the target location (21) to a filter area (46) of the direction filter (32). The probe further has an neutral particle detector (40) that detects the particles that has passed through the direction filter (32).