1. Hydrogen atomic clocks J. Mauricio López R. División de Tiempo y Frecuencia

2. Outline 1. The Maser effect 2. Hydrogen Maser clocks 0. Introduction 3. Frequency stability of a Hydrogen maser clock 4. Metrology applications 5. Conclustions

3. INTRODUCTION

4. The Nobel Prize in Physics 1989 "for the invention of the separated oscillatory fields method and its use in the hydrogen maser and other atomic clocks" "for the development of the ion trap technique" Norman F. RamseyHans G. DehmeltWolfgang Paul 1/2 of the prize 1/4 of the prize USA Federal Republic of Germany Harvard University Cambridge, MA, USA University of Washington Seattle, WA, USA University of Bonn Bonn, Federal Republic of Germany b.1915b.1922b.1913 d.1993

5. MASERMASER mplification by mission of adiation timulated icrowave

6. 1958 invensión del láser Charles H. Townes Arthur L. Schawlow Bell Labs “Infrared and optical Masers”, Phys. Rev., 1958

7. The MASER effect

8. Spontaneous emission Quantum system of two energy states EaEa EbEb

9. Spontaneous emission Quantum system of two energy states EaEa EbEb

10. Spontaneous emission Feymann diagram for the spontaneous emission effect EbEb EaEa h 1 Space Time

11. Stimulated emission Quantum system of two energy states Albert Einstein EaEa EbEb

12. Stimulated emission Feymann diagram for the stimulated emission Espacio Tiempo EbEb h 1 EaEa

13. Efecto Láser Short life time state Long life time state Ground state E1E1 E2E2 E3E3 The three basic energy levels configuration for a laser effect Optical pumping Quick decay Laser effect Short life time state Long life time state Ground state E1E1 E2E2 E3E3 The three basic energy levels configuration for a laser effect Laser radiation

14. Laser effect -Light amplification - Ground state Excited state photon

15. Basic elements of a Maser clock =Resonance cavity+Gain medium Interface+ Maser

16. Energy Ground state Energy levels of He Energy levels of Ne E2E2 E1E1 E3E3 Collisions He-Ne Long life time state Pumping (electric discharge) Quick decay Laser light 632.8 nm 0 eV 20 eV 18 eV Energy levels of a HeNe laser

17. F=2 F=1 F=0 F=1 F=0 F=1 F=0 1S 2S 2P P 1/2 P 3/2 121.6 nm 10.969 GHz 1.0578 GHz 1.420 GHz 59.19 MHz 177.6 MHz 23.7 MHz Electric interaction Fine structureHyperfine structure Energy levels of a Hydrogen maser clock Energy levels involve on the maser effect

18. Hydrogemn Masers realization

19. Magnetic shielding Coild Microwave cavity Glass bulb antenna Hydrogen atoms beam Depósito de Hidrógeno Selector de estados cuánticos Basic architecture of a Hydrogen Maser clock Vacuum chamber 27 cm TE 011

20. F=1 F=0 0% 25% 0% F=1 F=0 0% 25% F=1 F=0 0% 25% Quantum states selection F=1 F=0 25%

21. MixerAmplifier Phase detector Syntheziser  250 5 MHz Frequency output 1.420 405 752 GHz 1.4GHz 20.405 752 MHz VCXO 5 MHz Frequency synthesis chain for a Hydrogen Maser clock Phase lock loop

22. Actual architecture of a Hydrogen maser clock (KVARZ)

23. Active Hydrogen Maser

25. Frequency stability of a Hydrogen maser clock

26. Log (  y (  )) Log (  ), seconds -3.0 -2.00.01.02.03.04.05.06.07.0 1 Day 1 Month -9 -10 -11 -12 -13 -14 -15 -16 Hydrogen maser Rubidium Quartz Cesium Frequency stability of atomic clocks

27. Hydrogen maser Metrology applications

28. 123n... BIPM n-1 “independent” measurements n clocks CENAM´s clock ensemble of the ETP-1 M2M2 2 d Master Clock (Hydrogen Maser)

29. 1... Master clock 2 x 21 3 x 31 n x n1 x 23 =x 21 -x 31 ij

30. Log (  y (  )) Log (  ), seconds 0 |234567897.0 1 Day1 Month -9 -10 -11 -12 -13 -14 -15 -16 Time scale generation philosophy Hydrogen Maser Time scale algorithm UTC Time scale

31. . mauricio.lopez@cenam.mx + 52 (442) 211 0543 Hydrogen atomic clocks J. Mauricio López R. División de Tiempo y Frecuencia