F.T.S. Cesium-Beam Frequency Standard
name: label: maker
content: Frequency & Time Systems Inc.
notes: label: Description
content: This was the first in a series of cesium pre-production frequency standards developed in the 1970s by Frequency & Time Systems Inc. (FTS), Danvers, Mass. Two cesium clocks based on this early instrument, or “brassboard,” were aboard NTS-2, the second of the Navigation Technology Satellites (NTS) launched to validate the key concepts and hardware for the Global Positioning System (GPS). Built at the Naval Research Laboratory, Washington, D.C., NTS-2 was launched in June 1977.
label: Description
content: FTS was founded in Danvers, Mass., in 1971 and later became a subsidiary of Datum Inc. Symmetricom acquired Datum in 2002.
label: Description
content: Reference:
label: Description
content: Martin W. Levine, “Performance of a Preproduction Model Cesium Beam Frequency Standards for Spacecraft Applications,” <i>Proc. of the 10th Ann. Precise Time and Time Interval (PTTI) Appl. and Planning Meeting</i>, 1978, 169-193.
label: Description
content: Brief description of an atomic clock
label: Description
content: Electromagnetic waves of very specific and consistent frequencies can induce atoms to fluctuate between two energy states, and by measuring that frequency we can determine the “tick” of an atomic clock. A second in a cesium clock, for example, is defined as 9,192,631,770.0 cycles of the frequency that causes the cesium atom to jump between those states. Different atoms “tick” at different rates – strontium atoms tick about 10,000 times faster than cesium atoms – but all atoms of a given element tick at the same rate, making atomic clocks much more consistent than clocks based on macroscopic objects such as pendulums or quartz crystals.
label: Description
content: Steven Jefferts, physicist, National Institute of Standards and Technology.
label: Description
content: For additional background information go to:
label: Description
content: http://www.nist.gov/pml/div688/timekeeping.cfm
label: Location
content: Currently not on view
place: label: place made
content: United States: Massachusetts, Danvers
topic: label: general subject association
content: Modern Physics
label: general subject association
content: Science & Scientific Instruments
setName: label: See more items in
content: Medicine and Science: Modern Physics
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content: Time and Navigation
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content: Science & Mathematics
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content: Measuring & Mapping
creditLine: label: Credit Line
content: Naval Research Laboratory
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1982.0634.03
label: catalog number
content: 1982.0634.03
label: accession number
content: 1982.0634
objectType: label: Object Name
content: F.T.S. cesium-beam frequency standard
physicalDescription: label: Physical Description
content: metal (overall material)
label: Physical Description
content: plastic (overall material)
label: Measurements
content: overall: 8 5/16 in x 10 in x 16 in; 21.11375 cm x 25.4 cm x 40.64 cm
label: Measurements
content: cover: 5 1/16 in x 10 in x 16 in; 12.85875 cm x 25.4 cm x 40.64 cm