Milestone-Proposal:First Atomic Clock: Difference between revisions

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|a3=1947-1949
|a3=1947-1949
|a1=First Atomic Clock, 1948
|a1=First Atomic Clock, 1948
|plaque citation=The first atomic clock, developed by Harold Lyons at the National Bureau of Standards, utilized transitions of the ammonia molecule as its source of frequency and launched a technological revolutionWithin two decades of Lyon’s invention, the “atomic second” had replaced the Earth’s rotational rate as the reference for world timekeepingMany technologies, including the Global Positioning System (GPS), now rely on the accuracy of atomic clocks.
|plaque citation=The first atomic clock, developed near this site by Harold Lyons at the National Bureau of Standards, utilized transitions of the ammonia molecule as its source of frequency and revolutionized timekeepingFar more accurate than previous clocks, atomic clocks quickly replaced the Earth’s rotational rate as the reference for world timeAtomic clock accuracy soon enabled many new technologies, including the Global Positioning System (GPS).
|a2b=Washington Section (Region 2)
|a2b=Washington Section (Region 2)
|IEEE units paying=
|IEEE units paying=

Revision as of 00:46, 5 March 2016


To see comments, or add a comment to this discussion, click here.

Docket #:

This Proposal has been approved, and is now a Milestone


To the proposer’s knowledge, is this achievement subject to litigation? No

Is the achievement you are proposing more than 25 years old? Yes

Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes

Did the achievement provide a meaningful benefit for humanity? Yes

Was it of at least regional importance? Yes

Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes

Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes

Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes

Has the owner of the site agreed to have it designated as an IEEE Milestone? No


Year or range of years in which the achievement occurred:

1947-1949

Title of the proposed milestone:

First Atomic Clock, 1948

Plaque citation summarizing the achievement and its significance:

The first atomic clock, developed near this site by Harold Lyons at the National Bureau of Standards, utilized transitions of the ammonia molecule as its source of frequency and revolutionized timekeeping. Far more accurate than previous clocks, atomic clocks quickly replaced the Earth’s rotational rate as the reference for world time. Atomic clock accuracy soon enabled many new technologies, including the Global Positioning System (GPS).

200-250 word abstract describing the significance of the technical achievement being proposed, the person(s) involved, historical context, humanitarian and social impact, as well as any possible controversies the advocate might need to review.


IEEE technical societies and technical councils within whose fields of interest the Milestone proposal resides.


In what IEEE section(s) does it reside?

Washington Section (Region 2)

IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:

IEEE Organizational Unit(s) paying for milestone plaque(s):


IEEE Organizational Unit(s) arranging the dedication ceremony:


IEEE section(s) monitoring the plaque(s):


Milestone proposer(s):

Proposer name: Michael Lombardi
Proposer email: Proposer's email masked to public

Proposer name: Tom O'Brian
Proposer email: Proposer's email masked to public

Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.

Street address(es) and GPS coordinates in decimal form of the intended milestone plaque site(s):

There are two possible sites where the plaque can be located. Site 1 is located the closest to where the original Radio Building was located (see text below regarding original building site) , Site 2 would be seen more by the public and is also very near the site of the original work. The sites are described below:

Site 1 - International Drive NW, Washington, DC (across the street from Embassy of Kingdom of Bahrain)

There is a park owned by the U. S. State Department that is surrounded by various embassies. There is a retaining wall with a staircase into the park that would be a suitable location for the plaque. This is the nearest possible location to where the atomic clock was developed. A photograph (from Google Maps) is shown below. The coordinates are 38.941789, -77.067132.

Site 1 Retaining Wall.jpg

Site 2 - 4000 Connecticut Avenue NW, Washington, DC

One remaining piece of the old NBS campus remains, a pair of stone columns that once served as an entrance to the NBS campus (see photograph below from Google Maps). This site is slightly further away from where the work was accomplished than Site 1, but is on a major road where a steady stream of people would walk by and see the plaque. The columns make up the border of another little park, also owned by the U. S. State Department.

Site 2 Connecticut Avenue.jpg

Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.

Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. See descriptions and photographs of Site 1 and Site 2 above.

There is a historical marker located inside the retaining wall of Site 1 denoting the "Newton Apple Tree" that was planted in the park by NIST in 2000. A photograph of this plaque is shown below.

Newton Tree DC Site Sign 2010.jpg

Are the original buildings extant?

No. The Bureau of Standards relocated from Washington, DC to Gaithersburg, Maryland beginning in 1962 and ending in 1968. Lyons and his group worked in the Radio Building on the old DC campus and all of the buildings on that campus have been torn down. Based on comparisons of aerial photos of the DC campus with current images from Google maps, the approximate location of the Radio Building was where the embassies of Bahrain and the Kuwait cultural office are now located. The Bahrain embassy is located at 3502 International Drive NW in Washington, DC, and the Jordan embassy is located at 3500 International Drive NW. Here is an aerial view from Google Maps:

Former Site of Radio Building.jpg

Here is a photograph of the Radio Building (probably taken in the 1920s):

NBS radio building where clock was built.jpg

Here is a 1928 map of the NBS campus showing where the radio building was located with respect to Connecticut Avenue and Tilden Street:

1928 map showing radio building location.jpg

Details of the plaque mounting:

The plaque will be mounted outdoors, either on a stone retaining wall or a stone column (see description and photographs of Site 1 and Site 2 above).

How is the site protected/secured, and in what ways is it accessible to the public?

Both of the proposed sites are publicly accessible in an outdoor location.

Who is the present owner of the site(s)?

The United States State Department

What is the historical significance of the work (its technological, scientific, or social importance)? If personal names are included in citation, include justification here. (see section 6 of Milestone Guidelines)

The societal impact of atomic clocks has been immense. Many technologies that we take for granted rely on atomic clock accuracy, including mobile phones, Global Positioning System (GPS) satellite receivers, and the electric power grid.

Atomic clocks fundamentally altered the way that time is measured and kept. Before atomic clocks, the second was defined by dividing astronomical events, such as the solar day or the tropical year, into smaller parts. This changed in 1967, when the second was redefined as the duration of 9 192 631 770 energy transitions of the cesium atom. The new definition meant that seconds were now measured by counting oscillations of atoms, and minutes and hours were now multiples of the second rather than divisions of the day.

Atomic clocks also enabled astounding gains in timekeeping accuracy. For thousands of years prior to the invention of atomic clocks, the reference for world timekeeping was the Earth’s rotation rate, which was limited in accuracy to about one millisecond (one part in 10^8) per day. Quartz oscillators first appeared in the 1920s. The best quartz devices were eventually accurate enough to measure and record variations in the Earth’s rotation, but they were still limited in performance and sensitive to environmental changes. Atomic clocks provided a “quantum leap” in accuracy. Shortly after their invention, accuracies of parts in 10^10 became routine, and the accuracy of atomic clocks constructed at NBS/NIST has increased by roughly one order of magnitude per decade as shown in the illustration below.

Improvements in Atomic Clock Accuracy.jpg

The Scottish physicist James Clerk Maxwell was perhaps the first to recognize that atoms could be used to keep time. In an era where the Earth’s rotation was the timekeeping standard, Maxwell remarkably suggested to William Thomson (Lord Kelvin) that the “period of vibration of a piece of quartz crystal” would be a better absolute standard of time than the mean solar second, but would still depend “essentially on one particular piece of matter, and is therefore liable to accidents.” Atoms would work even better as a natural standard of time. Thomson wrote in the second edition of the Elements of Natural Philosophy, published in 1879, that atoms such as hydrogen or sodium are “absolutely alike in every physical property” and “probably remain the same so long as the particle itself exists.”

Even so, atomic clock experiments didn’t begin until about sixty years after the suggestions of Maxwell and Thomson. The early experiments were finally made possible by the rapid advances in quantum mechanics and microwave electronics that took place before, during, and after World War II. Most of the concepts that led to atomic clocks were developed by Isidor Isaac Rabi and his colleagues at Columbia University in the 1930’s and 40’s. As early as 1939, Rabi had informally discussed applying his molecular beam magnetic resonance technique as a time standard with scientists at the National Bureau of Standards (NBS). Rabi and his colleagues at Columbia first measured the cesium resonance frequency in 1940, estimating the frequency of the hyperfine transition as 9191.4 megacycles. This was relatively close to the number that would later define the second. Rabi’s work led to a Nobel prize in 1944, but atomic clock research at Columbia was mostly halted during World War II as scientists turned their attention to other areas and a demonstrable device was not built.

Building on the accomplishments of previous researchers, Harold Lyons and his colleagues at the National Bureau of Standards (NBS) in Washington, DC began working towards the development of the first atomic clock in 1947. The NBS clock was based not on cesium atoms, but instead used the 23.8 GHz inversion transition of the ammonia molecule as its source of frequency. After a period of intense and rapid research and development beginning in the spring of 1948, the new clock was first operated on August 12, 1948 and was publicly demonstrated in January 1949. Although its accuracy was quickly surpassed by other atomic clocks, it marked the beginning of the era of atomic timekeeping.

Photographs of first atomic clock:

Ammonia Clock 01061949.jpg

The world's first atomic clock as it appeared on January 6, 1949, the day of the first public announcement. An ammonia absorption cell consisting of about 8 meters of K-band waveguide is coiled around the 50 Hz electric clock. The clock atop the equipment racks was there for appearances only, so that the world would know that the new invention was a clock.

Condon (left) and Lyons (right) with Atomic Clock

Dr. Harold Lyons (right), inventor of the ammonia absorption cell atomic clock, observes, while Dr. Edward U. Condon, the director of the National Bureau of Standards, examines a model of the ammonia molecule (1949).

1948 Ammonia Molecule Clock Backside.jpg

A 1948 photograph showing the backside of the first atomic clock and the electronic components contained inside the two equipment racks. Lyons is kneeling on the right.

First Atomic Clock on Display at Smithsonian

The Division of Work and Industry of the Smithsonian Institute's National Museum of American History, holds the first atomic clock, constructed under Lyons’s direction at the National Bureau of Standards in 1948. The photograph shows the clock while on display at the museum.

What obstacles (technical, political, geographic) needed to be overcome?


What features set this work apart from similar achievements?


Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.

Patents:

[P1] H. Lyons and B. F. Huston, "Atomic Clock," United States Patent 2,699,503 (Applied for April 30, 1949, granted January 11, 1955).

Media:US_Patent_2699503.pdf

Journal Articles:

[J1] H. Lyons, "The Atomic Clock," Instruments, vol. 22, pp. 133-135, 174, December 1949.

Media:Lyons_Instruments_Dec_1949.pdf

[J2] "The Atomic Clock: An Atomic Standard of Frequency and Time," Journal of the Horological Institute of America, published in two parts in 1949 (issue 2, pp. 11-20 and issue 3, pp. 7-14).

A copy of the original journal paper is not available but the text is identical to the following document, which is provided here:

National Bureau of Standards, "The Atomic Clock: An Atomic Standard of Frequency and Time," NBS Technical Report 1320, 27 pages, January 1949.

Media:NBS_Report_1320_1949.pdf

[J3] H. Lyons, “The Atomic Clock: A Universal Standard of Frequency and Time,” American Scholar, vol. 19, pp. 159-168, April 1950.

Media:Lyons_American_Scholar_1950.pdf

[J4] H. Lyons, "Microwave Frequency Dividers," Journal of Applied Physics, vol. 21, pp. 59-60, January 1950.

Media:Lyons_J_Applied_Physics_1950.pdf

[J5] H. Lyons, “Spectral lines as frequency standards,” Annals of the New York Academy of Sciences, vol. 55, pp. 831-871, November 1952.

Media:Lyons_New_York_Academy_1952.pdf

[J6] H. Lyons, "Atomic Clocks," Scientific American, vol. 197, pp. 71-82, February 1957.

Media:Lyons_Scientific_American_1957.pdf

[J7] R. Beehler, “A Historical Review of Atomic Frequency Standards,” Proceedings of the IEEE, vol. 55, pp. 792-805, June 1967.

Media:Beehler_Proc_IEEE_1967.pdf

[J8] P. Forman, “Atomichron: The Atomic Clock from Concept to Commercial Product,” Proceedings of the IEEE, vol. 73, pp. 1181-1204, July 1985.

Media:Forman_Proc_IEEE_1985.pdf

[J9] M. A. Lombardi, T. P. Heavner, and S. R. Jefferts, "NIST Primary Frequency Standards and the Realization of the SI Second," NCSLI Measure: The Journal of Measurement Science, vol. 2, no. 4, pp. 74-89, December 2007.

Media:Lombardi_Measure_2007.pdf

[J10] M. A. Lombardi, "The Evolution of Time Measurement, Part 3: Atomic Clocks," IEEE Instrumentation and Measurement Magazine, vol. 14, pp. 46-49, December 2011.

Media:Lombardi_IEEE_IM_Magazine_2011.pdf

Conference Papers:

[C1] H. Lyons, "Microwave spectroscopic frequency and time standards," Proceedings of the IXth General Assembly of URSI, paper no. 91, pp. 47-57, 1950.

Media:Lyons_URSI_1950.pdf

[C2] P. Forman, “The first atomic clock program: NBS, 1947-1954,” Proceedings of the 1985 Precise Time and Time Interval Meeting (PTTI), pp. 1-17, 1985.

Media:Forman_PTTI_1985.pdf

[C3] D. B. Sullivan, "Time and Frequency Measurement at NIST: The First 100 Years," Proceedings of the 2001 IEEE Frequency Control Symposium, pp. 4-17, 2001.

Media:Sullivan_IEEE_FCS_2001.pdf

Books:

[B1] W. Snyder and C. Bragaw, “Achievement in Radio: Seventy Years of Radio Science, Technology, Standards, and Measurement at the National Bureau of Standards,” National Bureau of Standards Special Publication 555, October 1986.

Media:Snyder_NBS_SP_555_1986.pdf

[B2] T. Jones, "Splitting the Second: The Story of Atomic Time," Institute of Physics Publishing, Bristol and Philadelphia, 2000.

News Articles:

[N1] “The Atomic Clock: An Atomic Standard of Frequency and Time,” National Bureau of Standards Technical News Bulletin, vol. 33, no. 2, pp. 17-24, February 1949.

Media:NBS_Bulletin_February_1949.pdf

[N2] "Atomic Clock," Review of Scientific Instruments, vol. 20, no. 2, pp. 141-142, February 1949.

Media:RSI_News_Release_Feb_49.pdf

Miscellaneous:

Cartoon, "Ripley's Believe it or Not!," King Features Syndicate, 1953.

Figure 06 Ripleys 1953.jpg

Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to ieee-history@ieee.org. Please see the Milestone Program Guidelines for more information.


Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to ieee-history@ieee.org with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s).

Please recommend reviewers by emailing their names and email addresses to ieee-history@ieee.org. Please include the docket number and brief title of your proposal in the subject line of all emails.