NIST researchers have developed a new X-ray sensor design that nearly doubles the resolution of experimental X-ray sensors, enabling more precise identification of the X-ray “fingerprints” of different atoms. The new design, described in the Nov. 7 issue of Applied Physics Letters, can measure X-ray energies with an uncertainty of only 2.4 electron volts (eV), breaking through a long-standing 4.5 eV plateau in the performance of superconducting “transition edge” sensors (TES).
The primary design change was the addition of five copper ridges patterned on the sensor, perpendicular to the current flow, which blunts or softens the change in resistance from superconducting to normal. NIST holds a patent on the sensor design concept. The gentler transition reduces unexplained “noise” that degrades measurement precision. A second change was a reduction in device size from 400 to 250 micrometers square, which increases the rise in temperature caused by the X-rays, to better match the broader temperature range of the change in resistance.
NIST researchers expect to further improve sensor performance to reach the 2 eV resolution goal set by the National Aeronautics and Space Administration (NASA). Improved sensor performance will enable scientists to better measure tiny shifts in X-ray frequency caused by the motion of atoms in space, for example. The latest NIST work was supported in part by NASA and the NIST Office of Microelectronics Programs.
Source: https://www.nist.gov/news-events/news/2005/11/copper-ridges-nearly-double-x-ray-sensor-performance
Keywords: Transition-edge sensor, X-ray stopping power, Resolution, Superconducting, Metrology
