National Institute of Metrology (NIM), China

APMP/TCTF 2016, Da Nang, Viet Nam

Time KeepingØ UTC(NIM) : Time and Frequency Primary Standard in ChinaØ Clock ensemble: 6 active H-masers(MHM2010)+ 7 Cs Frequency Standards(5071A) Master clock-- H maser(No.35) 2 new H-masers(VCH 1003M) have joined the clock ensemble this year.

Time KeepingPerformance of UTC(NIM) (Oct. 2015-Sep. 2016)

BIPM G1 Calibration

BIPM 2016 G1 calibration in July

3 receivers at NIM have been calibrated by BIPM. Preliminary results are reasonably in line with the 2014 results.

NTSC calibration by NIM

The values are verificated by BIPM

Calibration values

TWSTFT system of NIM

u NIM01: AM22 linku NIM02: China sat-10u Temperature control

system: 25±1℃

NIM02NIM01

NIM01

NIM02

The uncertainty @ 1σ (Type A, Type B and link between NIM5 and H-271)

MJD y(NIM5-UTC) [×10-15] Duty cycle [%] utotal [×10-15]

57459.0 - 57479.0 -1.05 99.2 1.75

57604.0 - 57629.0 -0.53 96.9 1.52

57634.0 - 57654.0 0.68 97.5 1.53

NIM5 reports published on circular T

uA [×10-15] 0.6

uB [×10-15] 1.4

ulink/lab [×10-15] 0.2

utotal [×10-15] 1.5

Typical uncertainty budget of NIM5

Fountain NIM5

Target accuracy: 5e -16

Vacuum system Optical system

Ramsey cavity

MOT signal

Fountain NIM6

Strontium Optical Clock I

• NIM's first Sr clock– run out of Sr after 10 years,

build a new Sr oven and refill Sr

– leakage on the vacuum system, replace those old parts, better vacuum pressure, 2×10-10 Torr

– a new clock laser based on a 30 cm long reference cavity is being built

Strontium Optical Clock II

• NIM is going to build the second Sr clock on NIM's Changping Campus

• The vacuum system is under constructing• The laser system is under designing

Thank you for your attention!