Activity report from NICT

Transcription

1 Activity report from NICT APMP 2017 / TCTF meeting November, 2017 National Institute of Information and Communications Technology (NICT) Japan 1 1

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

3 Space time standards laboratory Atomic clock & Precise freq. measurement RM: T. Ido H. Ishijima, S. Itoh Sr opt. lattice H. Hachisu N. Nemitz In + ion-trap (K. Hayasaka) N. Ohtsubo Y. Li THz S. Nagano M. Kajita Cs primary M. Kumagai CSAC M. Hara Y. Yano VLBI 34m Antenna RM: M. Sekido M. Tsutsumi T. Kondo Super wideband Feed Japan Standard Time Analysis software E. Kawai H. Ujihara K. Takefuji Space time standards lab. Director: T. Ido H. Nezu (Technical Expert) (M. Hosokawa) (Y. Koyama) (Y. Hanado) RM: K. Imamura M: H. Saito H. Narita, M. Mizuno H. Usui Timescale LF station TelJJY, NTP, F. Nakagawa K. Matsubara Calib. Service H. Ito S. Tsuchiya (A. Machizawa) N. Kotake T & F transfer RM: R. Ichikawa M. Aida R. Tabuchi GNSS T. Gotoh TWSTFT M. Fujieda Wireless 2way N. Shiga T. Yasuda 3

4 Timescale JST : Time scale generation Clocks for generating UTC(NICT) : Cs 5071A : 18 (ensemble timescale) Anritsu H Masers : 1(source) + 2(backup) The behavior of UTC(NICT) : UTC UTC(NICT) < 20 ns. Stability ~ 2E 10 30d Allan deviation (log scale) -12 [UTC-UTC(NICT)]/ns manual frequency correction MJD freq. correction (1e-15) UTC(NICT) -HM3 (=HM4+AOG ) HM4 NET HM3- HM Averaging time (sec) 4

5 JST : Time scale generation Distributed system for Japan Standard Time generation Features NET from all distributed clocks linked via satellites Multiple generation of ensemble timescale (ET) by common database at remote sites (NET: NICT Cs Ensemble Timescale) 現在の状況 Synchronization of Kobe ensemble timescale (ET) to NET confirmed to be a few ns level Service in projected in June 2018 HQ-Kobe (ns) HM Cs 5

6 JST : Dissemination and Calibration LF stations LF40 : 1999 ~ LF60 : 2001 ~ System renewed (FY2012 FY2015) hagane-yama station 60kHz 23kW Ohtakadoya -yama station 40kHz 13kW Time stamping service ISO /IEC :2015 Calibration service Telephone JJY Access > 150 k /month. Accesses are increasing. 5,10M On site : 22 Remote: 1 ( ) FPGA based NTP server can accept up to 1 million requests / sec. Public NTP Accesses > 13 billion / day. (Oct. 2017) Leap second ( ) Well done. 6

7 Satellite T&F Transfer GNSS time link International time link For domestic link 3 receivers : 2 : Septentrio PolaRX 1 : Dicom GTR50 Real time Common view (RTCV) was developed for the link of NICTHQ Kobe, two LF stations. Calibrated by BIPM G1 trip (Apr. 2016, ub= 2.2 ns) TWSTFT Regular time link Asia and Domestic : Eutelsat 172A * The systems at Hawaii was terminated at the end of March * No Asia Europe link. Effort for resumption underway with other Asian & European laboratories. New system New TWSTFT modem is under development. 7

8 T&F Transfer : VLBI VLBI for T&F transfer Super-wideband system: Super wideband feed for 34m antenna ( GHz) Portable, wideband system (~2m) ready for T&F comparison Direct sampler, Analysis software Preliminary result of obseravtion UTC(NMIJ) UTC(NICT) comparison using 34m+ 2 2m antenna 8

9 T&F Transfer : ACES Join to ACES mission by ESA ACES (Atomic clock ensemble in space) Laser cooled Cs atomic clock & Active H maser in ISS. Launch in 2018, operation for 3yrs. NICT/NMIJ/Univ. Tokyo/RIKEN will join to ACES for a global link of optical clocks. One of 7 MW Ground Terminals will be settled at NICT (delegate of Japan). Platform for the MWL GT was completed on the rooftop of the NICT HQ building. Power delivery system under construction ACES MWL GT Ground Station NICT Google map UT NMIJ Developing optical clocks Univ.Tokyo: Sr, Yb, Hg NICT: Sr, Ca+, In+ NMIJ: Yb, Sr 9

10 Atomic clocks and Advanced techniques Microwave clocks Cs Fountain THz standard THz comb Chip Scale Atomic Clock (CSAC) NICT CsF1 (2006~) NICT CsF2 (under development) Optical clocks z r U Newly started since 2016 In + /Ca + Ion trap Sr Optical lattice 10

11 Optical clocks Sr optical lattice In operation since 2011 Uncertainty lately reduced to Correctio n(10-17 ) Uncer. (10-17 ) Blackbody radiation Lattice scalar/tensor dc Stark Quadratic Zeeman Density Line pulling Servo error Total New absolute frequency measurement (18) Hz Agreement with others of various institutes Uncertainty reduced to using the TAI-link H. Hachisu et al., Opt. Express 25, 8511 (2017) 11 In + ion with two Ca + as coolant CLK transition observed Abs. Freq. measured With uncertainty reduced to Correctio n(10-15 ) Uncer. (Hz) 1 st order Zeeman CLK laser stark BBR 0 <0.1 2 nd order Doppler secular micromotion Total Abs. freq.: (6.9) Hz N. Ohtsubo et al., Opt. Express 25, (2017)

12 CSAC (Chip Scale Atomic Clock) Test bench using Rb started clock oscillation in a desktop size Higher bandwidth of servo achieved by phase modulation (PM) instead of conventional frequency modulation (FM) THz reference frequency transfer via optical fiber Y. Yano et al., Appl. Phys. Lett. 111, (2017) 4 x precision at 0.3THz was demonstrated. S. Nagano et al., Appl. Phys. Express 10, (2017) 12

13 MRA MRA related activities ISO/IEC carried-in freq. calibration accredited since 2003 remote freq. calibration since 2006 will reconstruct management system for the accordance to the revision of ISO/IEC made on Nov CMC 5e-14 since 2007, KCDB updated in October 2016 GNSS calibration G2 trip KRISS, calibration implemented in May 2017, accepted by BIPM CSIR-NPL, projected in 1Q 2018 SG, hopefully follows, but schedule not yet forseen. 13

14 Japan Standard Time: Summary of topics Kobe sub station hopefully in service in mid T&F transfer: TWSTFT CP : KRISS NICT link continues. VLBI : super wideband system to be employed for frequency comparison Atomic clocks: Sr : Accuracy Abs. Freq. 4.3 x In + : Accuracy Abs. Freq. contributed to LoR in CCTF. CSAC: clock operation in a desktop test bench Integrated works projected: ACES : 1/7 Ground stations will be settled at NICT (in 2018). TWCP link with KRISS, VLBI link with INRIM Sr Time scale based on optical clocks 14