Transcript Document

Status Report on
Time and Frequency Activities
at NPL India
(APMP -TCTF 2012)
A. Sen Gupta, A. Chatterjee, A. K. Suri, A. Agarwal,
S. Panja, P. Arora, S. Yadav, P. Kandpal, M. P. Olaniya
(Wellington – Nov 2012)
1
Major activities
Time and Frequency Metrology
– Generation of UTC(NPLI)
– BIPM Link using GNSS
– BIPM Link using TWSTFT
Cs Fountain Frequency Standard
– Evaluation of the first Cs Fountain – in progress.
– Design and development of the second Cs Fountain.
Time Dissemination
– Dissemination by Telephone Time broadcast (Teleclock), and NTP server.
Calibrations
– Atomic Clocks (Rb & Cs Freq Standards), Time Interval Counter, Hour Meter,
Teleclocks, GPS timing receivers and Stopwatch.
– Providing traceability to IRNSS time scale.
Optical Frequency Standards
– Plans and initial activity on single trapped Yb+ ion standard.
IN
MHM2010
1PPS
IN Ф resolution= 2π(2-32)rad.
Freq. Resolution = 5E-19
out
1 PPS
Distribution
Amplifier-1
out
Hydrogen
Maser HM1
55 MHz
MHz
5 MHz out
Micro Phase
Stepper
out
5 MHz
5 MHz
To
Calibration
Lab
FREQUENCY
DOUBLER
UTC(NPLI)
1PPS
1PPS
1PPS
Cs Clock 2
10 MHz
To Fountain Lab
1PPS
5 MHz
Schematics of Generation of UTC(NPLI)- 1
1PPS
Cs Clock 3
1PPS
1PPS
5071A-C001
Cs Clock 6
1PPS
5071A-C001
1PPS
1PPS
5071A-C001
1
4
Automatic
2
3 Switching Unit
6
7
5
START
START
STOP
STOP
Time interval
counter 1
(25psec resolution)
@
Cs Clock 7
5071A-C001
Cs Clock 8
5071A-C001
Controller
Workstation
1PPS
To
Satellite
Links
5MHz
Cs Clock 3
5MHz
1PPS
5071A-C001
Cs Clock 6
5MHz
5071A-C001
1PPS
@
5MHz
Controller
Workstation
Multi-Channel
DMTD Phase
Comparator
IN
Micro Phase
Stepper(Aux)
out
5071A-C001
Freq. Resolution = 5E-19
UTC(NPLI)
5MHz
Cs Clock 2
IN Ф resolution= 2π(2-32)rad.
FREQUENCY
DOUBLER
5 MHz
UTC(NPLI) - Aux
To
Satellite
Links
1PPS
5MHz
Cs Clock 7
5071A-C001
Cs Clock 8
5071A-C001
5MHz
10 MHz
MHM2010
1PPS
out
IN
Distribution
Amplifier-1
out
1 PPS
55 MHz
MHz
5 MHz out
out
Hydrogen
Maser HM1
Micro Phase
Stepper
out
5 MHz
5 MHz
1PPS
To Fountain Lab
To
Calibration
Lab
1PPS
5 MHz
Schematics of Generation of UTC(NPLI)- 2
@
Photograph of the Clock Setup at NPLI
Schematics of GNSS and TWSTFT Links
@
1PPS
Workstation
for
controlling
SATRE
MODEM
operation
10 MHz
Beacon Receiver
Data
Antenna Control
unit
10 MHz
10 MHz
Saw Filter 2.5MHz
Pik Time TTS2A
Sngl Freq GPS Rx
Pik time TTS4
Dual Freq GPS Rx
PolaRx3eTR
Dual Freq GPS Rx
@
Workstation for
controlling GPS
Rx operation
10 MHz
1PPS
Distribution Amplifier-2
1PPS
1PPS
1PPS
Photographs of GNSS and TWSTFT Links
UTC(NPLI)-UTC(PTB), ns
Typical GPS P3 Link Results
MJD
σ = 1.2 ns
UTC(NPLI)-UTC(PTB), ns
Typical GPS Carrier Phase PPP Results
MJD
σ = 0.030 ns
Using NRCAN PPP Software developed by
Dept of Naural Resources, Canada
UTC(NPLI)-UTC(PTB), ns
Typical TWSTFT Results on the Eu-Asia Network
MJD
σ = 0.309 ns
UTC - UTC(NPLI) from BIPM Circ-T
UTC - UTC(NPLI), ns
200
195
190
185
180
175
170
56000
200
UTC - UTC(NPLI), ns
uA = 0.309 ns
uB = 7 ns
56050
56100
MJD
56150
56200
56250
UTCr - UTC(NPLI) – BIPM Pilot Expt
195
190
185
180
175
170
56000
56050
56100
56150
MJD
56200
56250
First Cs Fountain (India-CsF1)
Front View
490
2 x 55 l/s Ion Pumps
Cs Free Flight UHV Chamber
150
972
3 Layers of Magnetic shields
125
Microwave Cavities
236
.
300
C-Field Solenoid
Detection Zone
400
Octagonal MOT Chamber
2 x 20l/s Ion Pumps
850
India Cs-F1 is fully Operational and is presently being evaluated
India-CsF1 – Typical Results
Effect
Bias (x 10-15)
Uncertainty (x 10-15)
2nd 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, uB
* to be evaluated
1.0
(utotal)2 = (uA)2+(uB)2+(ulink/lab)2
Second Cs Fountain (India-CsF2)
• (1, 1,1) geometry for cooling and launching
• Two coils in anti-Helmholtz configuration
• Three pairs of rectangular Helmholtz coils
• Two detection beams of 10 mm x 10 mm
• Optical pumping to enhance the mf = 0 population
Time Dissemination
Teleclock Service
Internet Time Service
Domain name:
time.npli.in
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. We are planning 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
New Developments
We have just received funding to start work on a Single Trapped
Ion Optical Frequency Standard. We plan to work on Yb+ ions.
We plan to move some our activities to the New Metrology
Building next year.
Thank You for
your Attention