NIM, Changping, Beijing, China, 31 October, 2015

Development of Comparison System of Several

Atomic Clocks for Contribution to TAI and UTC

Asep Hapiddin, A. M Boynawan, Ratnaningsih

Research Center for Metrology-Indonesian Institute of Sciences, Puslit Metrologi-LIPI Komplek PUSPIPTEK Building 420, Setu, Tangerang Selatan, Indonesia 15314

Email: aseph@kim.lipi.go.id

Asia Pacific Workshop on Time and Frequency 2015

Outline

Motivation of work

Comparison System for 2 Atomic Clocks against UTC(KIM)

Result of Reference Time Delay Measurement

Conclusion and Future Plans

Motivation of Work

Atomic Clocks Ensemble and Status in RCM-LIPI

For performance checking purposes, the

operating parameters of all clocks

Using manual procedure once per day

All clocks are in normal condition

Continuously monitored

results

using

Motivation of Work

Atomic Clocks Ensemble and Status in RCM-LIPI

As supernumerary clock, Cs3 and Cs4 have not

contribute to TAI and UTC

Comparison System of Atomic Clocks for

Contribution to TAI and UTC

Reference Time Delay Measurement of Cs3 and Cs4

was initial research Activity Time interval Measurement Methods

Need

1st step

Comparison System for 2 Atomic Clocks against UTC(KIM)

Cs3,

Symmetricom

5071A

Arbitrary

Point

rear panel

Time Interval Counter, SR620

1 pps

1 pps

StopStart

10 MHz,

Ext. Ref

Cs1

Arbitrary

Point

rear panel

Time Interval Counter, SR620

1 pps

1 pps

StopStart

10 MHz,

Ext. Ref

Cs1,

HP5071A

10 MHz

Pulse Distribution

Amplifier

UTC(KIM)

input Cs3,

Symmetricom

5071A

Arbitrary

Point

rear panel

Time Interval Counter, SR620

1 pps

1 pps

StopStart

10 MHz,

Ext. Ref

Cs1

Cs4,

Symmetricom

5071A

Cs3,

Symmetricom

5071A

Time delay measurement of Cs3, UTC(KIM) and Cs4 against arbitrary point (AP).

Comparison Cs3 - AP UTC(KIM) - AP Cs4 - AP

ns

Time Delay 0.774 11458.600 9450.836

1st step: time delay measurement of UTC(KIM), Cs3 and Cs4 against arbitrary point (AP) directly. 1 pps front panel output of Cs3 was decided as arbitrary point

Comparison System for 2 Atomic Clocks against UTC(KIM)

rear panel

Time Interval Counter, SR620

1 pps1 pps

StopStart

10 MHz,

Ext. Ref

Cs1,

HP5071A

10 MHz

Pulse Distribution

Amplifier

UTC(KIM)

input

1 pps

Cs3,

Symmetricom

5071A

Cs4,

Symmetricom

5071A

rear panel

Switch,

Agilent 3499B

Time delay measurement results of Cs3 and Cs4 against UTC(KIM) using switch

The second step was time delay measurement of 1 pps rear panel output of Cs3 and Cs4 against UTC(KIM) using switching by Agilent 3499B.

Comparison Cs3 - UTC(KIM) Cs4 - UTC(KIM)

ns

Time Delay -11471.800 -2022.184

Arbitrary Point

9450.836 ns

11458.600 ns

0.774 ns

Cs3 Cs4 UTC(KIM)

0

2000

4000

6000

8000

10000

12000

Dela

y T

ime (

ns)

1 pps Signal of

Cs3-UTC(KIM) = -11471.800 ns

Cs4-UTC(KIM) = -2022.184 ns

The result of time delay measurement of Cs3 and Cs4

So, the reference time delay of Cs3 and Cs4 can be determined by: 𝒌𝑪𝒔𝟑 = ∆𝒕𝟑 − ∆𝒕𝟏 = 𝟏𝟑. 𝟗𝟕 ns and 𝒌𝑪𝒔𝟒 = ∆𝒕𝟒 − ∆𝒕𝟐 = 𝟏𝟒. 𝟒𝟐 ns

The result of time delay measurement Cs3 and Cs4

Result of the reference time delay measurement of Cs3

Dt1

Cs3 UTC(KIM)

Cs3 UTC(KIM)

= 11457.8 ns

Dt3= 11471.8 ns

Time Delay of Cs3 against

UTC(KIM) without switch

Time Delay of Cs3 against

UTC(KIM) using switch

Reference time

delay of Cs3 =

13.97 ns

Cs4 UTC(KIM)

Cs4 UTC(KIM)

Dt4 = 2022.2 ns

Time Delay of Cs3 against

UTC(KIM) without switch

Time Delay of Cs4 against

UTC(KIM) using switch

Reference time

delay of Cs4 =

14.42 ns

Dt2 = 2022.2 ns

Result of the reference time delay measurement of Cs4

Conclusion and Future Plans

By the manual monitoring of all clocks in the RCM-LIPI time scale system, it

was known if Cs1 as master clock for UTC(KIM) and two other clocks (Cs3 and

Cs4) are running in normal condition.

The initial research activity in developing comparison system of three

commercial Cs atomic clocks in RCM-LIPI has done. Then, the reference time

delay of two clocks (Cs3 and Cs4) as supernumerary clocks of Cs1 was

measured against UTC(KIM).

In the near future, we have planned to develop the automatic monitoring

system of all clocks.

We will improve the comparison system by continuous measurement with

automatic system. Then, we will report the reference time delay of each clock

to BIPM. So, all clocks may contribute to TAI and UTC.

Operating Parameters of Cs1, Cs2 and Cs4 From MJD 57174 - MJD 57234

57180 57200 57220 57240

-2

0

2

4

6

8

10

12

Cs-1

Cs-2

Cs-3

Ion

Pu

mp

(u

A)

MJD

Ion Pumps of Cs1, Cs3 and Cs4 (MJD57174 – MJD57234). Based on data in specification, normal condition is in the range 0-40 uA.

Operating Parameters of Cs1, Cs2 and Cs4 From MJD 57174 - MJD 57234

Oven monitors of Cs1, Cs3 and Cs4 (MJD57174 – MJD57234). Based on data in specification, normal condition is in the range 0-10 V for CBT and -10 to -5 for Osc

57180 57200 57220 57240

-10

-8

-6

-4

-2

0

2

4

6

8

CBT Cs-1

Osc Cs-1

CBT Cs-3

Osc Cs-3

CBT Cs-4

Osc Cs-4

Ov

en

Mo

nit

or

(V)

MJD

Operating Parameters of Cs1, Cs2 and Cs4 From MJD 57174 - MJD 57234

Osc Frequency Control of Cs1, Cs3 and Cs4 (MJD57174 – MJD57234). Based on data in specification, normal condition is in the range -95% to 95%.

57170 57180 57190 57200 57210 57220 57230 57240

-30

-25

-20

-15

-10 Cs-1

Cs-3

Cs-4

Os

c F

req

Co

ntr

ol (%

)

MJD

Operating Parameters of Cs1, Cs2 and Cs4 From MJD 57174 - MJD 57234

C-Field Control Current of Cs1, Cs3 and Cs4 (MJD57174 – MJD57234). Based on data in specification, normal condition is in the range 10.00 mA to 14.05 mA

57180 57200 57220 57240

12.12

12.13

12.14

12.15

12.16

12.17

12.18

12.19

12.20 Cs-1

Cs-3

Cs-4C

-Fie

d C

on

tro

l C

urr

en

t (C

s-1

,3, 4-m

A)

MJD

Operating Parameters of Cs1, Cs2 and Cs4 From MJD 57174 - MJD 57234

RF amplitude of Cs1 (MJD57174 – MJD57234). Based on data in specification, normal condition of RF amplitude A and B are in the range 0 to 100%.

57180 57200 57220 57240

26.0

26.5

27.0

27.5

28.0

28.5

29.0

A(%)

B(%)

RF

-Am

plitu

de (

A,B

,%)

MJD

Operating Parameters of Cs1, Cs2 and Cs4 From MJD 57174 - MJD 57234

Electron multiplier voltage of Cs1, Cs3 and Cs4 (MJD57174 – MJD57234). Based on data in specification, normal condition of electron multiplier voltage is in the range 1000 up to 2553 V

57180 57200 57220 57240

1000

1200

1400

1600

1800

2000 Cs-1

Cs-3

Cs-4E

lec

tro

n M

ult

iplie

r V

olt

ag

e (

Cs

-1,3

,4, V

)

MJD

Operating Parameters of Cs1, Cs2 and Cs4 From MJD 57174 - MJD 57234

Signal gain of Cs1, Cs3 and Cs4 (MJD57174 – MJD57234). Based on data in specification, normal condition of signal is in the range 14.4% up to 58%.

57180 57200 57220 57240

13

14

15

16

17

Cs-1

Cs-3

Cs-4S

ign

al G

ain

(%

)

MJD