Guide to the Harold Lyons Atomic Clocks collection

Administrative Information

Repository Information

Archives Center, National Museum of American History, 2007

P.O. Box 37012
 Suite 1100, MRC 601
 Washington, D.C., 20013-7012
 Phone: 202-633-3270

Conditions Governing Access note

The collection is open for research use.

Conditions Governing Use note

Collection items available for reproduction, but the Archives Center makes no guarantees concerning intellectual property rights. Archives Center cost-recovery and use fees may apply when requesting reproductions.

Immediate Source of Acquisition note

The collection was donated by Harold Lyons’s daughter, Sherrie L. Lyons, in January, 2000.

Processing Information note

Processed by Jeanne Sklar (intern) August 2001; supervised by Alison Oswald, archivist.

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Summary Information

Archives Center, National Museum of American History
Creator - (author).
Lyons, Harold, Dr., 1913-1998
Creator - (donor).
Lyons, Sherrie
Harold Lyons Atomic Clocks Collection
Date [inclusive]
2 Cubic feet; 6 boxes
Harold Lyons was a physicist whose primary interest was in atomic frequency standards and atomic clocks. The collection documents Lyons and his work with atomic clocks. The collection includes his research as manifested in published papers, presentations, reports, correspondence, laboratory notes, photographs and diagrams.

Preferred Citation note

Harold Lyons Atomic Clocks Collection, Archives Center, National Museum of American History, Smithsonian Institution.

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Biographical/Historical note

Harold Lyons was born February 16, 1913 in Buffalo, New York, and attended the University of Buffalo, graduating summa cum laude with a B.S. in Physics in 1933. After obtaining a Ph.D. in Nuclear Physics from the University of Michigan in 1939, he worked at the Naval Research Laboratories for two years and then joined the National Bureau of Standards (NBS) in 1941. In 1944, he was appointed chief of the Microwave Standards Section of an Interservice Radio Propagation Laboratory (IRPL) established at the NBS during World War II. He continued in that position after the war when the IRPL, in 1946, was reconstituted as the Central Radio Propagation Laboratory (CRPL).

Lyons’s work on microwave frequency standards led directly to his interest in atomic frequency standards and atomic clocks. On his initiative a substantial program of research and development was pursued in the Microwave Standards Section from 1948-1951. There under his direction the first operative atomic clock, based on the absorption of microwaves of ammonia, was constructed in 1948 and announced in early 1949.

Lyons remained with the CRPL after it was moved to Boulder, Colorado, in 1954, but left a year later to work in Hughes Aircraft Company’s Culver City, California, research labs. Here he continued his atomic physics research, particularly applications for the atomic clock, including satellite technology, and expanding to development work in lasers. He continued his work on lasers at Electro-Optical Systems Quantum Physics Division from 1960-1962. In the late 1960s and during the 1970s, he was an independent physics consultant and conducted research through an association with the University of California, Los Angeles.

Harold Lyons died March 23, 1998 in Los Angeles, California.

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Scope and Contents note

The Harold Lyons Papers, 1935-1991, show his professional interests, especially his research from the 1950s, as manifested in published papers, presentations, reports, correspondence, laboratory results, and photographs. The bulk of the collection consists of papers and presentations of Lyons and others in the atomic physics field. Most of Lyons’s work and the materials he collected address different aspects of microwave frequency.

Formats represented in the collection include published articles, typewritten and handwritten manuscripts, typewritten and handwritten personal correspondence, memorandums, photographs, diagrams, laboratory results, pamphlets, and newspaper clippings. The collection is arranged into five series.

Series 1, Biographical Information, 1955-1965; 1973, contains copies of Lyons’s curriculum vitae (circa 1955, 1962, and 1971) and his entries in Who’s Who in America and Who’s Who in The West. This series also has two folders with materials relating to two honors he received, the Franklin Institute Certificate of Merit, in 1958, and the U.S. Department of Commerce’s 25th Commemorative Award in 1973.

Series 2, Papers and Presentations, 1947-1962; 1973-1974, contains the journal articles and papers authored by Lyons and the conference and special presentations he gave during his career, most of which address research for aspects of the atomic clock. Included are papers he authored published in the Journal of Applied Physics, American Scholar, Scientific American, and Annals of the New York Academy of Sciences and presentations given at the National Bureau of Standards for the anniversary of the atomic clock.

Series 3, Correspondence, 1949-1991, contains general correspondence for the years 1949-1966, 1978, 1987, and 1991, as well as correspondence with the following individuals: Dirk Brouwer, Paul Forman, Polykarp Kusch, Koichi Shimoda, Wilbert F. Snyder, Charles H. Townes, and Jerrold R. Zacharias. The bulk of this series is incoming correspondence addressed to Lyons, although he did retain some copies of outgoing correspondence.

Series 4, Research, 1947-1958; 1970-1991, contains laboratory results for deuterated ammonia (via strip chart recordings) and general cesium atomic beam experiments through calibration of magnetic fields, calculation of c-fields in the magnetic chamber, and atomic beam measurements. It also contains brief information on other research interests, such as the International Scientific Radio Union, and scattered promotional materials for natural health and electrical products. In addition, this series contains a copy of the patent granted to Lyons and Benjamin F. Husten in 1955 for the atomic clock and photographs and diagrams relating to Lyons’s work on the atomic clock. Included are black and white photographs of Lyons and his colleagues with views of the clock as well as diagrams and charts included in published and unpublished work and presentations. Most of the photographs and diagrams are undated and unlabeled.

Series 5, Collected Background Research Materials, 1935-1982, contains papers and presentation materials focused on atomic physics, including papers published in journals, memoranda, technical reports, conference programs, and conference proceedings. One folder in this series has materials relating to the promotion of the atomic clock through pamphlets, speeches, papers, and one oversize item of reproduced newspaper clippings. A folder relating to a university course of lectures, most likely authored by Polykarp Kusch of Columbia University, on molecular beams is also included in this series. In addition, this series contains copies of two patents, one granted to Friedrich H. Reder in 1960 for molecular resonance devices, and the other, an Australian patent, applied for in 1958, for an invention dealing with a frequency selective method and system.

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Arrangement note

The collection is organized into five series.

Series 1, Biographical Information, 1955-1965; 1973

Series 2, Papers and Presentations, 1947-1962; 1973-1974

Subseries 1, Publications, 1947-1948; 1950-1953; 1957; 1959-1960; 1962; undated

Subseries 2, Presentations, 1946-1958; 1973-1974

Series 3, Correspondence, 1949-1991

Series 4, Research, 1947-1958; 1970-1991

Subseries 1, Laboratory Findings, 1952-1954; undated

Subseries 2, Other Research Interests, 1947-1957; 1970-1991

Subseries 3, Photographs and Diagrams, 1957; undated

Series 5, Collected Background Research Materials, 1935-1982

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Related Materials

Related Archival Materials note

Materials in the Archives Center

National Company (NATCO) Atomic Clocks Records, 1955-1968 (AC0547), contains related archival materials, principally on the development of the first commercial atomic clock, the Atomichron.

Materials in the National Museum of American History

The Division of Work and Industry, formerly the Division of Information, Technology and Communication, holds the first operative atomic clock, constructed under Lyons’s direction at the National Bureau of Standards in 1948.

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Controlled Access Headings


  • Articles--20th century
  • Correspondence--1940-2000.
  • Diagrams
  • Laboratory notebooks
  • Patents
  • Photographs--Black-and-white photoprints--Silver gelatin--1950-1960
  • Technical notes


  • Atomic absorption spectroscopy
  • Atomic clocks
  • Atomic frequency standards
  • Physics
  • Time--Systems and standards

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Collection Inventory

 Series 1: Biographical Information, 1955-1965, 1973

Box Folder

Curriculum vitae and biographical data, 1955-1965

1 1

Franklin Institute Certificate of Merit, 1958

1 2

U.S. Department of Commerce 25th Commemorative Award, 1973

1 3

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 Series 2: Papers and Presentations, 1947-1962, 1973-1974

 Subseries 1: Publications, 1947-1948, 1950-1953, 1957, 1959-1960, 1962, undated

Box Folder

"Cesium, Atomic Beam Frequency Standard", undated

1 4

The Microwave Frequency Standard at the Central Radio Propagation Laboratory, 1947

1 5

"Microwave Frequency Measurements and Standards", 1948

1 6

"Microwave Frequency Dividers", 1950

1 7

"The Atomic Clock, A Universal Standard of Frequency and Time", 1950

1 8

"Microwave Measurement of the Dielectric Properties of Gases", 1950-1951

1 9

"Spectral Lines as Frequency Standards", 1952

1 10

"Microwave Absorption Spectrum of ND3", 1953

1 11

"Atomic Clocks", 1957

1 12

"Amazing Maser" and "Maser, Iraser, and Laser", 1959, 1960

1 13

"Molecular Beam Devices", 1962

1 14

 Subseries 2: Presentations, 1946-1958, 1973-1974

Box Folder

Presentations, 1946-1958

1 15

National Bureau of Standards, 1973

1 16-17

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 Series 3: Correspondence, 1949-1991

Box Folder

General correspondence, 1949-1991

2 1-2

Dirk Brouwer, 1951-1955

2 3

Paul Forman, Smithsonian, 1982-1985, 1990

2 4-5

Polykarp Kusch, 1949-1956

2 6

Koichi Shimoda, 1955-1957

2 7

Wilbert F. Snyder, 1950-1966, 1978, 1987

2 8-11

Charles H. Townes, 1954-1955

2 12

Jerrold R. Zacharias, 1952-1953

2 13

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 Series 4: Research, 1947-1958, 1970-1991

 Subseries 1: Laboratory Findings, 1952-1954, undated

Box Folder

Deuterated ammonia, undated

3 1

Cesium atomic beams, undated

3 2

Magnetic field calibrations, 1952-1954, undated

3 3

C-Field calculation, 1952, undated

3 4

Atomic beam measurements, 1952, undated

3 5

 Subseries 2: Other Research Interests, 1947-1957, 1970-1991

Box Folder

International Scientific Radio Union, 1947-1957, 1978, undated

3 6

Health and product-related, 1970, 1981, 1990-1991, undated

3 7

Miscellaneous notes and papers, undated

3 8

Patent, 1958

3 9

 Subseries 3: Photographs and Diagrams, 1957, undated

Box Folder

Photographs, undated

3 10
Map-case Drawer Folder

Photographs, undated

3 19 1
Box Folder

Diagrams, 1957, undated

3 11
Map-case Drawer Folder

Diagrams, undated

3 19 1

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 Series 5: Collected Background Research Materials, 1935-1982

Box Folder

Publications and papers, undated

3 12-13

Publications and papers, 1935-1953

4 1

Publications and papers, 1954-1959

4 2-5

Publications and papers, 1959-1979

5 1-3
Map-case Drawer Folder

Atomic clock promotional material, 1955

3 19 1
Box Folder

Atomic clock promotional material, undated

5 4

Presentations and conference materials, 1950-1982

5 5

Physics 261, molecular beams course, undated

5 6

Patents, 1958, 1960

5 7

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