Status Report on Time and Frequency Activities at CSIR-NPL India (APMP -TCTF 2016) S. Panja, A. Agarwal, D. Chadha, P. Arora, P. Thorat, S. De, S. Yadav, P. Kandpal, M. P. Olaniya and V. N. Ojha (Da Nang, Vietnam Nov 2016) 1
Time and Frequency Metrology Generation of UTC(NPLI) BIPM Link using GNSS BIPM Link using TWSTFT Calibrations Major activities Atomic Clocks (Rb & Cs Freq Standards), Time Interval Counter, Hour Meter, Teleclocks, GPS timing receivers and Stopwatch. Providing traceability to IRNSS time scale. Time Dissemination Dissemination by Telephone Time broadcast (Teleclock), and NTP server. Cs Fountain Frequency Standard Evaluation of the first Cs Fountain in progress. Design and development of the second Cs Fountain. Optical Frequency Standards activities on single trapped 171 Yb + based frequency standard.
10 MHz out out out 5 MHz Schematics of Generation of UTC(NPLI) To Fountain Lab To Calibration Lab Hydrogen Maser - HM1 MHM2010 5 MHz 1 PPS 5 MHz out Distribution Amplifier-1 IN 5 MHz IN Micro Phase Stepper 5 MHz UTC(NPLI) FREQUENCY DOUBLER Cs Clock 2 5071A-C001 Cs Clock 3 5071A-C001 Cs Clock 6 5071A-C001 1 4 2 3 6 7 5 Automatic Switching Unit START START STOP Time interval counter (25psec resolution) - - - @ To Satellite Links Cs Clock 7 5071A-C001 Cs Clock 8 5071A-C001 Controller Workstation
Typical Set-up for Timing Traceability Link Between CSIR-NPL and BIPM A-Hydrogen MASER / 5MHz Distribution Amplifier Micro Phase Stepper UTC (NPLI ) Distribution Amplifier Correction Bank of Cs- Clocks Clock Inter Comparison Data Processing Unit LAN/WAN NTP Server UTC(NPLI) GNSS Receiver UTC-UTC (NPLI) BIPM Server NPLI Server TWSTFT
Photograph of the Clock Setup at NPLI
10 MHz 1PP S 10 MHz Data 10 MHz Schematics of GNSS and TWSTFT Links TTS4 Multi Freq GNSS Rx Saw Filter 2.5MHz Antenna Control unit PolaRx3eTR Multi Freq GNSS Rx Beacon Receiver Workstation for controlling SATRE MODEM operation - - - @ - - - @ Workstation for controlling GNSS Rx operation 10 MHz Distribution Amplifier-2
Photographs of GNSS and TWSTFT Links
UTC(NPLI)-UTC(PTB), ns Typical GPS P3 Link Results MJD σ = 1.2 ns
UTC-UTC(NPLI) and UTC-UTCr (NPLI), ns UTC(NPLI) and UTCr(NPLI) Results from April, 2012 to August, 2016 UTCr(NPLI) UTC(NPLI) MJD Note: From MJD56019 to 56349 added -190.0 in UTC(NPLI) and UTCr(NPLI)
Time Dissemination Teleclock Service Internet Time Service Domain name: time.nplindia.org
Calibration Services We are providing UTC Traceability to the Time scale of the Indian Regional Navigational Satellite System (IRNSS). This Time scale is known as the IRNWT and is maintained by the Indian Space Research Organization (ISRO). The technique used presently is all in view GPS P3. Now recently we started to supplement this with a dedicated TWSTFT link. We are providing Time & Frequency in house Calibration Services to Test & Calibration Labs from Govt. and Industries for the calibration of Rb & Cs Atomic Clocks, Time Interval Counters, Hour meters, Teleclocks, GPS receivers and Stop watches
Remote Calibration using GNSS Common View Set up at Remote Location Set up at NPL
400 300 236. 125 150 972 490 First Cs Fountain (India-CsF1) Front View 2 x 55 l/s Ion Pumps Cs Free Flight UHV Chamber 3 Layers of Magnetic shields C-Field Solenoid Microwave Cavities Detection Zone Octagonal MOT Chamber 2 x 20l/s Ion Pumps 850 India Cs-F1 is fully Operational and is presently being evaluated
Typical Uncertainty Budget Effect 2 nd Order Zeeman Shift 50.46 Black Body Radiation -17.27 Gravitational Red Shift 19.6 Cold Collisional Shift -12.0 2.4 Light shift 0.0 0.2 Background gas collisions Cavity pulling Rabi, Ramsey Pulling Majorana transitions 0.0 0.0 0.0 0.0 Spectral impurity 0.0 0.2 Microwave leakage 0.0 0.1 DCP 0.0 0.2 0.1 0.01 0.1 0.1 Total(U B ) 39.8 2.45 Total u A = 1.74 x 10-15 d -1
Live contribution of NPLI-CsF1 to TAI* ( appears in Circular-T) ftp://ftp2.bipm.org/pub/tai//publication/cirt/cirt.335 (December 2015) *The fountain is not working at the moment as the environmental control needs to be replaced.
2 nd Cs Fountain at CSIR-NPL Design features: (1, 1,1) geometry for cooling and launching to reduce light shifts. Optical pumping to enhance the S/N ratio. Four-feed cavity design to reduce phase shifts. Better estimation of systematic shifts. Improved accuracy and stability
India-CsF1 Typical Results Effect Bias (x 10-15 ) Uncertainty (x 10-15 ) 2 nd order Zeeman 50.8 0.1 AC Stark (BBR) -16.5 0.2 Collisions * 1.0 (approx) Gravity 19.4 0.1 Other effects * 0.1 (approx) Total, u B 1.0 * to be evaluated (u total ) 2 = (u A ) 2 +(u B ) 2 +(u link/lab ) 2
Single Trapped Ytterbium Ion Optical Standard Presently, we are up to: (I) Design and fabrication of the ion trap and vacuum chamber suitable for precision experiments (II) Estimation of the systematic uncertainties outcomes are fed for better trap design (III) Lasers & Optics design and alignment (IV) Design and fabrication of the helical resonator and atomic oven (V) Design and fabrication of RF drivers of laser frequency modulation (VI) Electronic modules and subsystems for the experimental setup
Basic Principal and Energy Levels repump 1 RF Trap Energy levels of 171 Yb + 2 4f 13 5d6s 1 D[3/2] 3/2 1 4f 13 5d6s 3 D[3/2] 1/2 0 1 4f 14 6p 2 P 1/2 1 0 atom ion Continuum 4f 14 5d 2 D 3/2 935.2 nm 760 nm (quadrupol 2 e) 1 4f 14 6s6p 1 P 1 4f 14 6s 2 1 S 0 369.5 nm 399 nm 4f 14 6s 2 S 1/2 1 0 369.5 nm 6s 2 4f 13 2 F 7/2 4 3
Expected Systematics: Comparison of two Clock Transitions For frequency standards -> Octupole transition (E3) is a better choice than the quadrupole transition (E2)
Ion in the trap
Identifying The Suitable Trap Geometry
New Developments and future plans: Want to participate in APMP region Inter-country inter-comparison of stop watch and timer Want to calibrate our receivers with a calibrated travelling Receive of Gr-I lab. Work in progress about developing new frequency standard in The optical region based on single trapped ytterbium ion Work in progress about establishing a new Time Scale in the New Metrology Building of CSIR-NPL We are working towards Improving Tele-clock service and replacing with Fonoclock and also working towards improving NTP service facility.
Thank You for your Attention