Activity report from NICT

Transcription

1 Activity report from NICT APMP 2013 / TCTF meeting November, 2013 National Institute of Information and Communications Technology (NICT) Japan 1 1

2 Activities of our laboratory Atomic Frequency Standards G Precise Atomic clocks development Opt. clock Opt. comb VLBI Generation, Measurement, and dissemination of the T&F standard Space-Time Measurement G at Kashima VLBI technique for precise T&F transfer Japan Standard Time G at Koganei T&F transfer Techniques by using the Optical fibers And satellites TWSTFT GNSS Cs primary Generation and Dissemination Of Japan Standard Time Opt. fiber 2

3 Staffs in our laboratory Space-Time Standard Laboratory Y. Hanado, Tech. Expert: 1 M. Hosokawa Y. Koyama Japan Standard Time G. K. Imamura, T. Iwama Researcher: Tech. Expert: 2 Space-Time Measurement G. R. Ichikawa Researcher: Guest researcher: 1 Tech. Expert: 1 Atomic Frequency Standards G. T. Ido Researcher: Guest researcher: 2 Tech. Expert: 4 Space-Time Meas. G. at Kashima M. Sekido Researcher: 3 Tech. Expert: 1 3

4 JST : Time scale generation Clocks for generating UTC(NICT) : Cs 5071A : 18 (ensemble timescale) Anritsu H-Masers : 3 (signal source) The behavior of UTC(NICT) : UTC UTC(NICT) < 20 ns, Stability reaches to 1E-15. Kobe LF60 LF40 Kashima Satellite Tokyo Time Transfer As a new approach, distributed generation system of Japan Standard Time is under development. Ensemble timescale At Kobe ~ Ensemble timescale At Tokyo The experimental room has been completed in the Kobe branch. 4

5 JST : Dissemination and Calibration LF stations LF40 : 1999 ~ LF60 : 2001 ~ System renewal of both stations have started. hagane-yama station 60kHz 23kW Ohtakadoya -yama station 40kHz 13kW Time stamping service Calibration system Telephone JJY Access > 1.4E5 /month. Accesses are increasing. Public NTP FPGA-based NTP server can accept up to 1 million requests / sec. Accesses > 200 million / day. Time calibration signal (in LF) repeater Precision < 10 ms Cover area < 10 m NTP Server Inter net signal repeater < 10 m 5

6 T&F Transfer Regular operation GPS time link: Septentrio dual freq. receivers are used for TAI TWGPPP link. Research of advanced techniques Advanced TWSTFT (DPN*, Carrier Phase) New analysis software for both GNSS and VLBI Optical fiber transfer TWSTFT: Asia : IS-8 => GE-23 Asia -EU : AM-2 (used for TWGPPP link) Asia -Hawaii US : GE-23, AMC1. NICT VLBI for T&F transfer AM2@80 GE23@172 6

7 T&F Transfer : TWSTFT carrier phase Due to H-maser M odified Allan deviation Measurement stability of TWSTFT carrier phase Due to phase variation induced by room temperature variation 0 km 100 km 1000 km km km Averaging time [s] 0 km: free from stability of ref.-clocks 100 km: Tokyo-Kashima, H-maser comparison 1000 km: Tokyo-Okinawa, H-maser comparison Sr-Sr link was also tested km: NICT-PTB, UTC(k) or H-maser comparison Short-term stability 1s) is independent of baseline length. 7

8 T&F Transfer : VLBI, analysis software VLBI for T&F transfer New wideband feed system, Effective sampling procedure, High-speed correlation procedure, are in progress. Original transportable telescope is evaluated for transportation. => NICT - NMIJ experiment, soon. 34mφ New analysis software for GNSS, VLBI and SLR Novel multi-technique space geodetic analysis software (C5++) is under development. Estimation of common parameters (clocks, troposphere, orbits) among different techniques redundancy Supports local-tie information between the techniques. 1.6mφ NICT NMIJ 1.6mφ 8

9 Atomic clocks and Advanced techniques Microwave clocks Cs Fountain Yb + standard Toward the THz standard NICT-CsF1 NICT-CsF2 (2006~) (under development) Optical clocks z r U THz comb Ultrastable laser Ion-trap Optical lattice Optical comb 9

10 Cs fountain primary frequency standard NICT-CsF1 Typical uncertainty is 1.4 x since Recent Upgrading: Improvements of vacuum Installations of a rapid adiabatic passage method. NICT-CsF2 NICT-CsF1 CSO (Cryogenic Sapphire Oscillator) NICT-CsF2 using a pure optical molasses is under development. Most systematic shifts are evaluated at a level below 5 x uncertainty. Frequency stability of 3 x /τ 1/2, and averages down to the statistic uncertainty at the level Hz Frequency Hz NICT-CsF2 10

11 Optical clocks Ion-trap optical clock NICT develops both type of optical frequency standards Optical lattice clock In + -Ca + Ion trap : 87 Sr lattice clock : In + In + NICT Stationary Satellite 16 Height : 36,000 km 1 In + & 2 Ca + trapped in a linear trap Next goal In + 3 time clock operation using 1 S 0-3 P 1 detection Sr Sr Next goal PTB Cryogenic clock NICT-PTB direct comparison Via TWCP 11

12 NICT-PTB direct comparison 1E-14 ADEV 1E-15 Blue: all data during 4days Black: long coherent data at June 26 th averaging time (s) 250 Histogram 200 Identical frequency confirmed with an uncertainty < Occurrences E E E Sr(PTB)/Sr(NICT)-1

13 New approaches to THz standard Toward the THz standard Trial to establish a new frequency standard in THz domain. Absolute frequency measurement system is under development. Measurement stability : 1E-15 level around 300 GHz. 636GHzsignal was also measured with the same scheme. Measurement system and measured stability of 300 GHz. 13

14 Summary of topics Japan Standard Time: Distributed generation system is under development. System renewal of two LF stations have started. T&F transfer: TWSTFT Carrier Phase exp. of NICT PTB was achieved. Short-term stability = 3 x 1s. The first trial of Sr(NICT) Sr(PTB) by TWSTFT CP. Atomic clocks and advanced technique: In the optical clocks, In + ion-trap clock and 2 nd Sr lattice clock are under development. Toward the THz standards, basic techniques are in progress. 14