Accession Number:

ADA639437

Title:

NIST F1 and F2

Descriptive Note:

Conference paper

Corporate Author:

NATIONAL INST OF STANDARDS AND TECHNOLOGY BOULDER CO TIME AND FREQUENCY DIV

Report Date:

2010-11-01

Pagination or Media Count:

9.0

Abstract:

The National Institute of Standards and Technology operates a cesium fountain primary frequency standard, NIST-F1, which has been contributing to International Atomic Time TAI since 1999. During the intervening 11 years, we have improved NIST-F1 so that the uncertainty is currently delta integralintegralsub 0 approximately 3x10exp -16, dominated by uncertainty in the blackbody-radiation-induced frequency shift. In order to circumvent the uncertainty associated with the blackbody shift, we have built a new fountain, NIST-F2, in which the microwave interrogation region is cryogenic 80 K, reducing the blackbody shift to negligible levels. We briefly describe here the series of improvements to NIST-F1 that have allowed its uncertainty to reach the low 10-16 level and present early results from NIST-F2.

Subject Categories:

  • Operations Research
  • Test Facilities, Equipment and Methods
  • Telemetry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE