Heavner, T.
, Parker, T.
, Shirley, J.
, Kunz, P.
and Jefferts, S.
(2010),
NIST F1 and F2, PTTI Conference proceedings 2010, Rastin, VA, US, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=907715 (Accessed May 19, 2026)
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
NIST F1 and F2
Published
Author(s)
Thomas Heavner, , , ,
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 δf/fo ≅ 3 × 10-16, dominated by uncertainty in the Blackbody radiation inducedfrequency 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 (80K) reducing the blackbody shift to negligible levels. We briefly describe here the series of improvements to NIST-F1 which have allowed its uncertainty to reach the low 10-16 level and present early results from NIST-F2.Proceedings Title
PTTI Conference proceedings 2010
Conference Dates
November 15-18, 2010
Conference Location
Rastin, VA, US
Pub Type
Conferences
Download Paper
Keywords
atomic clock, frequency standards
Citation
Issues
If you have any questions about this publication or are having problems accessing it, please contact [email protected].
Created November 15, 2010, Updated May 7, 2026