Status Report on Time and Frequency Activities at NMIJ, AIST

Transcription

1 November 26, 2012 APMP TCTF meeting Status Report on Time and Frequency Activities at NMIJ, AIST Takeshi Ikegami Time and Frequency Division, National Metrology Institute of Japan, AIST Director Deputy-Directors Principal Research Scientist Divisions Time & Frequency Lengths & Dimensions Mechanical Metrology Acoustics & Vibration Metrology Temperature & Humidity Fluid Flow Material Properties & Metrological Statistics Structure of NMIJ Structure of National Metrology Institute of Japan (NMIJ) Sections Time Standards Wavelength Standards Frequency Measurement Systems Length Standards Dimensional Standards Mass & Force Standards Pressure & Vacuum Standards Legal Weighing Metrology Acoustics & Ultrasonics Vibration & Hardness Thermometry Cryogenic Thermometry Radiation Thermometry Humidity Standards Gas Flow Standards Liquid Flow Standards Legal Flow Metrology Thermophysical Fluid Properties Metrological Statistics & Particle Measurement Divisions Electricity & Magnetism Electromagnetic Waves Quantum Radiation Inorganic Analytical Chemistry Organic Analytical Chemistry Materials Characterization Legal Metrology Dissemination Technology Metrology Management Center Sections Electricity Standards Section 1 Electricity Standards Section 2 High Frequency Standards Field Strength Standards Laser Standards Optical Radiation Ionizing Radiation Radioactivity & Neutron Inorganic Standards Environmental Standards Organic Standards Polymer Standards Biomedical Standards Surface & Thin Film Standards Nanopore Standards Calibration & Verification Pattern Approval Policy & Planning Office Service & Quality Office International Metrology Cooperation Office Metrology Training

2 NMIJ Time and Frequency Division (Chief : F.L.Hong) Time Standards Section (Members: T.Ikegami, K.Hagimoto, S.Yanagimachi,, A. Takamizawa, T.Tanabe) Cs atomic fountain primary standards, cryogenic sapphire oscillators, calibration service of phase-noise Wavelength Standards Section (Members: F.L.Hong, H.Inaba, K.Hosaka, M.Yasuda, D.Akamatsu, I.Hirano, S.Okubo, T.Tanabe, A.Onae) Yb/Sr optical lattice clocks, narrow linewidth lasers, optical frequency combs, calibration service of laser frequencies Frequency Measurement Systems Section (Members: M.Amemiya, K.Watabe, T.Suzuyama, M.Wada, A.Okuda) Timekeeping of UTC(NMIJ), time and frequency transfer (GPS, TWSTFT, otptical fiber), calibration service of frequency including remote calibration Time Standards Section Members: T. Ikegami K. Hagimoto S. Yanagimachi A. Takamizawa T. Tanabe Cesium Atomic Fountains and Cryogenic Sapphire Oscillators

3 Atomic fountains in NMIJ 2 fountains and 1 experimental apparatus NMIJ-F1: Calibration of TAI (Long-term operation with uncertainty of ) Frequent reports to BIPM (25 calibration reports to BIPM in recent 5 years). Reference for NMIJ-F2 and optical lattice clocks on demand. NMIJ-F2: Under construction. Target uncertainty < Better stability & smaller uncertainty with large numbers of atoms. Precise reference for optical lattice clocks. LVIS, Truncated beam etc.. Truncated beam fountain: New proposal (Phys.Rev.A 82 (2010) ). In the step for proof of the principle. The obtained data will be used for the improvement of NMIJ-F2. 5 Calibration of TAI using NMIJ-F1 2.0E-14 y(nmij-f1)-y(tai) 1.0E E+00 f(nmij-f1)-f(tai) f(pfs)-f(tai) Earth qu ake -1.0E MJD 25 reports to BIPM in recent 5 years until Feb The operation has stopped since March 2011 (Earthquake). Then, Cs atom resource was exhausted. Opening the vacuum chamber, we will replace the cavities to make NMIJ-F1 more reliable. 6

4 NMIJ-F2 Microwave cavities which are part of the vacuum vessel (S. R. Jefferts et al., Proc IEEE Int. Freq. Control Symp. p. 6) Decrease of the uncertainty caused by microwave power dependence Laser power :100 mw per beam (001) configuration Increase of the number of cold atoms Higher frequency stability NMIJ-F2 (under construction) 7 Launching atoms Saturated around 80 mw 8

5 Ramsey fringes Width 1.2 Hz, Contrast Cryogenic sapphire oscillators CSO1: Kept at liquid Nitrogen temperature CSO2: Room temperature. Used for the evaluation of CSO1. Phase noise calibration service has started, using the CSO as a ultra-low phase noise reference.

6 Optical Frequency and Wavelength Standards Section Members: F.-L. Hong H. Inaba K. Hosaka M. Yasuda D. Akamatsu I. Hirano S. Okubo T. Tanabe A. Onae Research activities Yb optical lattice clock Sr optical lattice clock Narrow linewidth laser Optical frequency combs Contribution to the redefinition of the second

7 Yb optical lattice clock at NMIJ Blue MOT Green MOT M. Yasuda, H. Inaba, T. Kohno, T. Tanabe, Y. Nakajima, K. Hosaka, D. Akamatsu, A. Onae, T. Suzuama, M. Amemiya, F.-L. Hong, Appl. Phys. Express 5, (2012). f (Hz) Frequency comparison b/w three institutes (arxiv: ) (PRL 103, ) (this work) M. Yasuda, H. Inaba, T. Kohno, T. Tanabe, Y. Nakajima, K. Hosaka, D. Akamatsu, A. Onae, T. Suzuama, M. Amemiya, F.-L. Hong, Appl. Phys. Express 5, (2012).

8 Uncertainty budget Effect Shift (Hz) Uncertainty (Hz) Lattice ac Stark Blackbody Second order Zeeman Gravitational Probe light Collision Hyperpolarizability Yb Total (4.1x10-16 ) UTC(NMIJ) UTC(NMIJ) TAI 0.68 TAI SI Total (3.6x10-15 ) M. Yasuda, H. Inaba, T. Kohno, T. Tanabe, Y. Nakajima, K. Hosaka, D. Akamatsu, A. Onae, T. Suzuama, M. Amemiya, F.-L. Hong, Appl. Phys. Express 5, (2012). Sr-Yb dual optical lattice clock at AIST Motivation Build up 87 Sr/ 171 Yb optical lattice clocks in a new chamber. 1) Contribution to the Sr lattice clock community; 2) As a second optical clock to be used for the evaluation of the Yb lattice clock; 3) Measurement of the Sr/Yb frequency ratio with an uncertainty beyond the Cs limit; 4) Contribution to the experimental demonstration of alpha variation. V. I. Yudin et al. Atomic clocks with suppressed blackbody radiation shift PRL (2011). Dual clock with suppressed BBR shift D. Akamatsu, Y. Nakajima, H. Inaba, K. Hosaka, M. Yasuda, A. Onae, F.-L. Hong, Opt. Express 20, (2012).

9 1 S 0-1 P 88 1 Sr MOT B field off B field (35G/cm) on ~ Sr MOT TOF Image 3mm ~7.7mK 0ms 1ms 2ms 3ms 4ms D. Akamatsu, Y. Nakajima, H. Inaba, K. Hosaka, M. Yasuda, A. Onae, F.-L. Hong, Opt. Express 20, (2012). Applications to optical lattice clocks using narrow linewidth combs ν~1 Hz Nd:YAG 1Comb is phase locked to the ultra-stable laser at 1064 nm. ν Frequency comb High-finesse optical cavity at 1064 nm 2Continuous wave lasers are phase locked to the comb. ν Yb lattice clock Clock laser (578 nm) Sr lattice clock 2 nd cooling laser (689 nm) PDH lock Ultra stable laser at 1064 nm The comb transfers the linewidth to other lasers at some wavelengths. Sr lattice clock Clock laser (698 nm) K. Iwakuni, H. Inaba, Y. Nakajima, T. Kobayashi, K. Hosaka, A. Onae, F.-L. Hong, Opt. Express 20, (2012).

10 Frequency Measurement Systems Section Members: M. Amemiya K. Watabe T. Suzuyama M. Wada A. Okuda Keeping Time scale and T&F Transfer Frequency measurement systems section Section chief: Masaki Amemiya,, 4 researchers, 1 technical staff - Time keeping of UTC(NMIJ) - Time and frequency transfer, such as GPS carrier phase, TWSTFT, and optical fiber - Calibration service of time and frequency and its R&D work

11 UTC(NMIJ) generation system and time transfer link UTC(NMIJ) is generated by reference signal from one hydrogen maser steered by an AOG. Clocks at NMIJ - 4 hydrogen masers 2 RH401A made by Anritsu 1 SD1T01A made by Anritsu 1 CH1-75A made by KVARZ Cs clocks 5071A with high performance beam tube Time Transfer Link - UTC PPP (GPS carrier phase) using Z12-T: main time transfer tool - TWSTFT : backup tool Cs clocks and H-masers Temperature controlled chambers for 5071A CH1-75A Temperature controlled chamber for SD1T01A Hydrogen masers (RH401A) Cs atomic clocks and new hydrogen masers (RH401A, CH1-75A and SD1T01A) are placed in temperature controlled chambers. The temperature variation of inside of the chambers is better than +/-0.2 deg. C. CH1-75A is the reference oscillator of UTC(NMIJ)

12 Measurement system for UTC(NMIJ) UTC-UTC(NMIJ) in 2011

13 Relative frequency offset of NMIJ to UTC in 2011 σ= Histogram of relative frequency offset of NMIJ to UTC σ=

14 Multi channel high precision DMTD time comparison system (1) Purpose: Upgrading and stabilizing UTC(NMIJ) Target: Improvement in single digit for atomic clock comparison Existing measurement system Measuring 1 pps every 2 minute by time interval counter Developing system Simultaneously measuring 8 channels with 100 MHz signal every second Resolution: (provisional) Temperature stabilization of circuit board is under investigation Prototype Multi channel high precision DMTD time comparison system (2) Temperature stabilization of circuit board is under investigation

15 Earth station configuration Europe link air-conditioned Storehouse (Converter & SSPA) ASIA link ASIA link station (1.8 m, 10 W) This frontend part is installed the temperature controlled system.

16 Europe link station ( 2.4 m, 10 W) The direction was changed toward AM-2, but new RX BPF, Radio license are needed. Temperature controlled box (outdoor unit) Specification setting range : setting accuracy : ±1 Measurement result setting temperature e :

17 19th Meeting of the CCTF WG on TWSTFT NMIJ (Tsukuba, Japan) September, Institutes 27 participants Thank you very much! Relative frequency offset of NMIJ to UTC in 2010 and 2012 Year Month Day (yyyy/mm/dd)

18 Long-term characteristic on frequency remote calibration service Thank you for your attention!