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Time and Frequency Division

MISSION

The mission of the Time and Frequency Division is to advance measurement science and to provide time and frequency standards and measurement services to commerce, industry, and the public.

SCOPE

The Time and Frequency Division, located at NIST’s Boulder, Colorado, campus, has 3 NIST fellows, 32 scientists/engineers, 4 technicians, 52 NIST associates, and 6 administrative support staff, as of January 2010. Its FY 2009 budget was about $15.6 million, 68 percent of which was STRS funding.

The programs of the Time and Frequency Division are effectively focused on achieving its stated objectives. Accordingly, the division programs focus on four principal thrusts: (1) the realization of national and international time and frequency standards (Coordinated Universal Time, UTC) with the greatest accuracy and precision; (2) the dissemination of time and frequency through a wide variety of measurement services directed to customers at all levels, from industrial and research customers with the most stringent needs to the general public; (3) research on future time and frequency standards and dissemination methods; and (4) quantum computing with trapped ions, which evolved directly from research on new atomic clocks and which has become a major NIST-wide focus area.

The division has established itself as a leader in these areas, providing a level of organizational performance (e.g., demonstrated frequency accuracy and stability, scope and quantity of time dissemination services, publication of scientific results) which exceeds that of any metrologic laboratory in the world. The division’s outstanding staff members have produced the world’s best time standard, the world’s smallest atomic clock, and the world’s most popular time dissemination system.

There has been progress in improving the existing laboratory space, and improved operational efficiency has been achieved as a result. The new building under construction will be available for occupancy in 2012 and will further improve the performance and reliability of the laboratory space. It is recommended that efforts to maintain and upgrade existing laboratory facilities continue, even after the new building is completed.

The division has an exceptionally talented group of permanent and temporary staff members to perform its primary responsibilities. This is particularly true in the areas of fundamental improvements to primary frequency standards and in the field of quantum logic. However, the ratio of permanent staff to associates has been declining, thereby producing less opportunity for a new generation of staff with long-term focus on



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7 Time and Frequency Division MISSION The mission of the Time and Frequency Division is to advance measurement science and to provide time and frequency standards and measurement services to commerce, industry, and the public. SCOPE The Time and Frequency Division, located at NIST’s Boulder, Colorado, campus, has 3 NIST fellows, 32 scientists/engineers, 4 technicians, 52 NIST associates, and 6 administrative support staff, as of January 2010. Its FY 2009 budget was about $15.6 million, 68 percent of which was STRS funding. The programs of the Time and Frequency Division are effectively focused on achieving its stated objectives. Accordingly, the division programs focus on four principal thrusts: (1) the realization of national and international time and frequency standards (Coordinated Universal Time, UTC) with the greatest accuracy and precision; (2) the dissemination of time and frequency through a wide variety of measurement services directed to customers at all levels, from industrial and research customers with the most stringent needs to the general public; (3) research on future time and frequency standards and dissemination methods; and (4) quantum computing with trapped ions, which evolved directly from research on new atomic clocks and which has become a major NIST-wide focus area. The division has established itself as a leader in these areas, providing a level of organizational performance (e.g., demonstrated frequency accuracy and stability, scope and quantity of time dissemination services, publication of scientific results) which exceeds that of any metrologic laboratory in the world. The division’s outstanding staff members have produced the world’s best time standard, the world’s smallest atomic clock, and the world’s most popular time dissemination system. There has been progress in improving the existing laboratory space, and improved operational efficiency has been achieved as a result. The new building under construction will be available for occupancy in 2012 and will further improve the performance and reliability of the laboratory space. It is recommended that efforts to maintain and upgrade existing laboratory facilities continue, even after the new building is completed. The division has an exceptionally talented group of permanent and temporary staff members to perform its primary responsibilities. This is particularly true in the areas of fundamental improvements to primary frequency standards and in the field of quantum logic. However, the ratio of permanent staff to associates has been declining, thereby producing less opportunity for a new generation of staff with long-term focus on 54

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the NIST mission. This imbalance in the ratio is influenced by the current structure of the overhead for permanent and associate staff. Examples of the division’s high-impact accomplishments include the aluminum ion “logic clock” (best in the world for precision), the femtosecond laser frequency combs enabling the world’s most precise intercomparisons, with a wide range of other applications in diverse fields such as astronomy and biological/chemical detection, remote time and frequency calibrations (best-in-the-world accuracy and usability), phase- noise metrology, NIST network time services, and chip-scale atomic clocks and sensors. An important area of concern is related to the declining and inadequate funding supplied to division core services, such as network time services, radio stations, time and frequency calibrations, and maintaining the operation of the F-1 time standard. ASSESSMENT OF THE DIVISION Following is the panel’s assessment of the overall quality of the Time and Frequency Division (including opportunities for improvement) in terms of the three criteria as requested by the NIST Director (see Chapter 1). Assessment Relative to Technical Merit The technical quality of the work of this division is among the best in the world. The Time and Frequency Division is indeed an important national asset and fills a major need. The staff is first-rate, and its accomplishments, as measured by the academic standards of publications, conferences, and professional recognition, are first-rate. Some important highlights of the division’s accomplishments include the following:  Realization of the SI Second: —Primary frequency standards: best-in-the-world accuracy with the atomic standard F-1 (3 × 10-16 frequency uncertainty reported to BIPM [the International Bureau of Weights and Measures]). —The upcoming cryogenic F-2 primary standard, which will improve the above accuracy by the factor three (to 10-16 uncertainty). —One of two best timescales in the world in terms of accuracy and stability.  Measurement Services: —Remote time and frequency calibrations: best-in-the-world accuracy and usability. —Phase-noise metrology: unique capabilities, best-in-the-world metrology. —NIST network time services: the world’s most heavily used Web clock (more than 3 billion hits per day). —NIST radio stations: best-in-the-world accuracy, stability; heavily used. —Global time service: low cost, ubiquitous 10 ns uncertainty service. The division has a new Web-based capability to track timescales across many laboratories in several countries around the world. —Time Measurement and Analysis Service: real time, 15 ns uncertainty; expanded to the Sistema Interamericano de Metrologia (SIM) Time Network. 55

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—Timescale coordination in North, Central, and South America; Department of State funding (generates international goodwill). —Phase-noise metrology: extending capability to 800 GHz, a capability that does not exist today, as driven by advancing Department of Defense technology requirements. Advancing the art of oscillator characterization beyond phase noise to acceleration sensitivity measurements, at frequencies and scales not achieved before.  Research and Development: —Aluminum ion logic clock, best in the world (8.7 × 10-18 uncertainty). —Single-ion optical frequency standards: mercury ion second-best in the world (1.6 × 10-17 uncertainty). —Cold neutral atomic optical standards: calcium (excellent short stability); ytterbium lattice, one of the world’s best. —Femtosecond laser frequency combs: the world’s most precise frequency intercomparisons (1 × 10-19 uncertainty); the world’s top-performing octave-plus spanning combs. Significantly advancing the range of applications with the optical comb to fields as diverse as astronomy and bio/chem detection. —Chip-scale atomic sensors: numerous first demonstrations (chip clock, chip magnetometer); progress in expanding the “microsensor” work from clocks, to magnetometers and gyros. The chip-scale-device activities are state of the art for miniature devices that could have significant applications in the commercial world. The next level of development of these devices to multiple device fabrication by means of clean-room-based wafer fabrication should be encouraged and supported.  Quantum Information Processing: —Sole technology to demonstrate all seven DiVincenzo criteria for scalable quantum computing; first single-atom quantum logic gate; first deterministic entanglement; first robust error correction; first quantum teleportation of massive particles; first quantum Fourier transforms. —The ability to perform quantum processing and an extensive demonstration of quantum logic operations is very significant. Assessment Relative to Adequacy of Resources Human Resources The Time and Frequency Division has an exceptionally talented group of permanent and temporary staff members, well suited to perform its primary responsibilities. This is particularly true in the areas of fundamental improvements to primary frequency standards and in the field of quantum logic. However, the ratio of permanent staff to associates has been declining, thereby producing an older and more experienced staff with fewer young developing staff and more inertia with respect to changes in the direction of work. This approach may serve the scientifically fashionable areas of research, but it does not serve the mission of NIST as it relates to advancing commerce. 56

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The division has become overly dependent on temporary NIST associates, with over 60 percent of its staff in that category. These individuals are generally very well suited for conducting frontier research, but their awareness and interest in the fundamental mission of the division, particularly with respect to its responsibility to “our nation” is limited. A continuity of association with NIST and the Time and Frequency Division as provided by permanent employment provides the best opportunity to develop this familiarity. Such permanent staff members then have the ability to identify areas of investigation and pertinent capabilities of high relevance to serving our nation. The current overhead structure also tends to encourage the use of temporary staff. At the NIST level, changing to a more uniform burdening of salaries should result in gradually increasing the permanent-to-temporary staff ratio. The division’s productivity will be improved by increasing the number of technical support personnel. As an example, the most senior staff member associated with the establishment of the NIST timescale and Network Time Services is spending an excessive amount of his time responding to an IT audit. This work should be done primarily by IT-knowledgeable support staff, with guidance supplied by the senior staff member. Such senior staff should be focusing on improving the timescale and the NIST ability to disseminate such information. Similarly, it is desirable to have electronics technicians. The alternative is to invest graduate student and postdoctoral researchers’ time in this area. Budgets An area of concern with respect to the Time and Frequency Division is related to the declining and inadequate funding supplied to primary standards and the NIST timescale. This area does not seem to be fully appreciated. Increased attention to clearly identifying the value that NIST products have to areas of practical impact is necessary. An increase in the level of discretionary funding at the division level would allow division leadership greater ability to address this need. Ultimately, laboratory management will have to make a conscious decision to shift resources to these areas. The division’s network time distribution continues to lead the world, with more than 3 billion automated synchronizations per day of computer clocks and network hardware, and the usage continues to grow. However, this area of core metrology has been chronically underfunded. The greatest need in this area is to hire a new staff member as an apprentice to begin learning this program from the developer and current project leader. Evidently, a lack of funds prevents this from happening, jeopardizing the long-term health of NIST’s most heavily used service. ARRA funding for a new NIST time code radio station, or for upgrading the existing WWVB time code station, should be a high priority for NIST. Attempts to identify a suitable East Coast location for a new station have failed for a variety of reasons beyond NIST’s control. A major upgrade of the existing WWVB time code station appears to be the best alternative, and NIST should focus on this option and take all necessary actions to implement the upgrade. Miniature atomic clocks and instruments are doing well with Defense Advanced Research Projects Agency (DARPA) support, but there is no budget mechanism to provide for the continuity of this work when the support runs out or takes its course to 57

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completion. This area is a good example of NIST doing its job in helping to address a major need with specialized capabilities, but the work is not high on the budgetary priority list. Budget flexibility should be developed to provide more stable support to this important area. The next level of development of these devices to multiple device fabrication by means of clean-room-based wafer fabrication should be encouraged and supported. Three points of note remain. Resource limitations prevent the division’s engaging in more extensive technology transfer; this area of the NIST mission needs more attention and support. The infusion of funds from the ARRA has been very helpful, and appears to have been used wisely. And finally, the Ion Storage Group appears to be the only group with adequate resources and adequate space. Major Equipment and Facilities Poorly performing laboratories have been a significant problem for the division— poor control of temperature, vibration, and other environmental conditions has seriously compromised the progress on and efficiency of research and metrology. The ongoing construction of the new advanced laboratory for Boulder should lead to major improvements for the division and for all of NIST Boulder. Progress to this end should be commended. However, the new laboratory probably will not be ready for occupation until approximately early 2012, so the division will continue to be hindered by obsolete laboratory conditions until then. With the level of accuracy and precision sought by the division, environmental control in its laboratories is critically important. There has been some progress in improving the existing laboratory space, particularly improving the temperature control for the NIST timescale. This should continue even after the completion of the new building. Although there has been considerable improvement in the state of facilities, there remain major problems associated with the lack of space in the phase-noise measurement area and in the optical frequency standards area. Assessment Relative to Achievement of Stated Objectives and Desired Impact As an excellent example of serving the nation, the NIST Internet Time Service continues to grow in use, with an average of more than 3 billion automated synchronizations of computers and network devices every day. The service continues to expand the number and geographical diversity of servers across the United States to meet the continually growing demand. Frequency combs are a major advance and a very enabling technology, transferable through optical fibers to characterize all frequencies through clockwork. Praiseworthy efforts are underway to connect this technology to problems in spectroscopy biochemistry, astronomy, the generation of arbitrary optical waveforms, and the generation of a new type of ultra-stable microwave and millimeter-wave sources. The accuracy of the time standard has been realized, but its reliability needs to be improved. The use of highly accurate time should be promoted through sharing, portability, and new applications. Optical clocks sent through fibers appear to have much 58

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promise. The calcium clock’s portability and fast stabilization are important features for expanding outside connections and opportunities. America needs to be covered by radio time. Another group of antennas or an additional transmitter site is clearly needed to expand opportunities and commercialization. These ongoing efforts need encouragement and high-level support. The division’s research staff is doing exceptionally well in their topical areas. By all research university metrics, they are giving excellent performance. However, because they are embedded in NIST, their outreach and impact on real-world problems could be expanded. Every research staff member should be concerned about the impact that his or her work is having on the world and about the possibilities of solving previously insurmountable measurement, technical, and scientific problems with their techniques and new instruments. NIST could do a better job of translating its science and technology into commercial value. For example, the chip-scale device activities, which could have significant commercial applications, should be supported for their next level of development. Some of its very important services require higher attention, for example, the network time services, radio time stations, time and frequency calibrations, and maintaining the operation of the F-1 time standard. The division’s core metrology mission is underfunded and inadequately appreciated, as judged by its budgetary support. The human resources are primarily through contractors, who come and go without knowing what the mission really is. The transient nature of scientists’ engagement with the division promotes National Science Foundation-style investigations whereby science is done for knowledge, not as a directed force to solve national problems. A final comment is an encouragement for the Time and Frequency Division to continue to clarify the relationships between all of its technical products and commercial, military, and related scientific applications. CONCLUSIONS AND RECOMMENDATIONS Conclusions The technical work in the Time and Frequency Division is excellent and serves as a model for other laboratories in the world. The physical facilities in which this work is performed have shown much improvement since the previous NRC panel visit to the division in 2008, but some of these facilities remain substandard, and inadequate space continues to be a problem. The construction of the new laboratory, appropriate for the work and technology of the division, is on schedule to be occupied in 2012 and will start a new era for expected experimental accomplishments of the division. The Time and Frequency Division conducts a solid portfolio of efforts effectively directed toward achieving the stated division goals. The technical quality of its work in each area of emphasis is excellent and is the best or among the best in the world. The division is indeed an important national asset that fills a major need. The staff are first- rate, and their accomplishments, as measured by the academic standards of publications, conferences, and professional recognition, are of the highest quality. 59

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Recommendations The following recommendations address means to enhance the quality of the division’s products and the ability of the division to achieve its objectives.  Research applied toward solving problems of national interest should be encouraged by rewarding work in this area through increased recognition and increased funding and by including the concept as part of the division strategic goals. —The level of technology transfer should be increased and ways devised whereby technology developed at NIST over years and decades is transferred to commercial use for the best value to the public. —Investments in areas of research should be prioritized and reviewed so as to better serve the objectives and charge of the Time and Frequency Division and NIST as a whole.  The goal of increasing the ratio of permanent to associate staff for the division and its management should be established. —An overhead structure that supports increasing the number of permanent staff should be developed. —The need for support staff should be reexamined to ensure that the time spent by senior researchers is best utilized. —The need for expanded funding for core metrology functions and services is apparent. —A higher level of discretionary funds should be provided for division management to help with future strategies and directions and with the current mission.  Budgetary structures should be established that allow a smooth transition and “gap funding” between phases of externally supported work, such as work supported by DARPA.  Adequate support should be ensured for the ongoing upgrading of facilities, both new facilities and facility renovations. 60