Radiation shield and optical lattice clock including radiation shield
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Solution Overview
Problem
Optical lattice clocks face challenges in achieving higher accuracy due to the influence of blackbody radiation, particularly room temperature radiation leaking through apertures in radiation shields, which causes significant uncertainty in clock transition frequencies despite efforts to reduce blackbody radiation shifts.
Innovation Solution
A radiation shield design that considers the geometrical shape of the inner wall surface to minimize the difference in blackbody radiation shifts between mirror and diffuse reflection conditions, using a ray tracing method to calculate and optimize the reflection characteristics, allowing for the reduction of uncertainty to 10^-19 or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a radiation shield with apertures is used to allow atom transport and laser beam passage, then the optical lattice clock can operate, but room temperature radiation leaks into the shield through apertures causing significant blackbody radiation shifts and uncertainty in clock transition frequencies
Solution Approach 1:
The patent introduces an intermediary radiation shield structure with specifically designed inner wall surfaces that mediate between the external environment and the atoms. The shield includes reflective surfaces positioned to intercept and redirect blackbody radiation away from the atom region, reducing the direct impact of thermal radiation on clock transition measurements while maintaining operational functionality through apertures.
Solution Approach 2:
The patent changes the geometric parameters of the radiation shield's inner wall surfaces, including curvature radius, aperture positioning, and surface orientation angles. By optimizing these parameters, the shield modifies the path and intensity of blackbody radiation reaching the atoms, thereby reducing the blackbody radiation shift from approximately 10^-16 to 10^-18 level while preserving necessary atom transport and laser beam passage.
2Measurement precision
If the inner wall surface is designed to reduce blackbody radiation shifts, then measurement precision improves, but the design complexity increases due to需要考虑 reflection characteristics and geometrical shape optimization
Solution Approach 1:
The patent employs asymmetric inner wall surface designs where different sections of the radiation shield have different curvature radii and orientation angles. This asymmetric configuration is optimized to redirect blackbody radiation away from the atom region while simplifying the overall design compared to complex multi-component systems. The asymmetric geometry creates favorable reflection patterns that reduce blackbody radiation exposure without requiring additional active control mechanisms.
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 optimized radiation shield design effectively reduces the uncertainty in clock transition frequencies to 10^-19 or less, enhancing the accuracy of optical lattice clocks and extending this improvement to other atomic species like Yb, Mg, Cd, and Hg.
Implementation Method 1
a condition where the inner wall surface exhibits mirror reflection
Implementation Method 2
a condition where the inner wall surface exhibits diffuse reflection
Implementation Method 3
the radiation emitted by the inner wall surface, incoming radiation leaking in from the outside through the apertures, and a reflection component of the emitted radiation and incoming radiation
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
Provided according to an embodiment of the present disclosure is a radiation shield 10 including a shield wall surrounding a hollow region capable of accommodating therein atoms for an optical lattice clock 100, the shield wall having, provided therein, at least two apertures communicating with outside. A geometrical shape of an inner wall surface of the shield wall is configured such that a difference between BBR shifts found under two conditions does not exceed a predetermined value over a range of position of atoms, the BBR shifts being caused in atoms 2 by emitted radiation emitted by the inner wall surface, incoming radiation leaking in from the outside through the apertures, and a reflection component of the emitted radiation and incoming radiation at the inner wall surface, the two conditions being a condition where the inner wall surface exhibits mirror reflection and a condition where the inner wall surface exhibits diffuse reflection, the range being where clock transition operation is carried out in the optical lattice clock, the inner wall surface facing the hollow region. Provided according to other embodiments of the present disclosure also are the optical lattice clock 100 including such a radiation shield, and a design method for the radiation shield.