2011-08-30
org.kosen.entty.User@75bd298f
Taehee Jeong(thj77)
The NIST JNT system measures very small electrical noise in resistors, a common electronic component, when they are cooled to the water triple point temperature. This “Johnson noise” is created by the random motion of electrons, and the signals they generate are directly proportional to temperature. The electronic devices measuring the noise power are calibrated with electrical signals synthesized by a superconducting voltage source based on fundamental principles of quantum mechanics. This unique feature enables the JNT system to match electrical power and thermal-noise power at the triple point of water, and assures that copies of the system will produce identical results. NIST researchers recently improved the apparatus to reduce the statistical uncertainty, systematic errors and electromagnetic interference. Additional improvements in the electronics are expected to further reduce measurement uncertainties.
국가
미국
소속기관
(연구소)
연락처
303-497-7341 http://www.nist.gov/pml/quantum/constant-033011.cfm
책임자
Sam Benz samuel.benz@nist.gov
