Hydrogen atomic clocks

Hydrogen atomic clocks

J. Mauricio López R.División de Tiempo y Frecuencia

Outline

1. The Maser effect

2. Hydrogen Maser clocks

0. Introduction

3. Frequency stability of a Hydrogen maser clock

4. Metrology applications

5. Conclustions

INTRODUCTION

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. Ramsey Hans G. Dehmelt Wolfgang Paul 1/2 of the prize 1/4 of the prize 1/4 of the prize

USA 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.1915 b.1922 b.1913d.1993

MASER

mplification by

mission of

adiation

timulated

icrowave

1958 invensión del láser

Charles H. Townes

Arthur L. Schawlow

Bell Labs

Bell Labs

“Infrared and optical Masers”, Phys. Rev. , 1958

The MASER effect

Spontaneous emission

Quantum system of two energy states

Ea

Eb



Ea

Eb ab EEhE


Feymann diagram for the spontaneous emission effect

Eb

Ea

h1

Spac

e

Time

ba EhE 1

Stimulated emission


Albert Einstein

Ea

Eb

Stimulated emission

Feymann diagram for the stimulated emission

Espa

cio

Tiempo

Eb

h1

Ea

h1

h1

11 2 hEhE ab

Efecto Láser

Short life time state

Long life time state

Ground stateE1

E2

E3

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 stateE1

E2

E3

The three basic energy levels configuration for a laser effect

Laser radiation

Laser effect

-Light amplification - Ground state

Excited state

photon

Basic elements of a Maser clock

= Resonance cavity + Gain medium

Interface +

Maser

Ener

gy

Ground state

Energy levels of He

Energy levels of Ne

E2

E1

E3

Collisions He-NeLong 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

F=2

F=1

F=1

F=0

F=1

F=0

F=1

F=01S

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 structure Hyperfine structure

Energy levels of a Hydrogen maser clock

Energy levels involve on the maser effect

Hydrogemn Masers realization

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

27 c

m TE011

F=1

F=0

0%0%

25%25%

0%

F=1

F=0

0%25%

25%

F=1

F=0

0%0%

0%25%

Quantum states selection

F=1

F=0

25%25%

25%25%

Mixer Amplifier

Phase detector

Syntheziser

250

5 MHz Frequency output

1.420 405 752 GHz

1.4GHz20.405 752 MHz

20.405 752 MHz

VCXO

5 MHz

Frequency synthesis chain for a Hydrogen Maser clock

Phase lock loop

Actual architecture of a Hydrogen maser clock (KVARZ)

Active Hydrogen Maser

Active Hydrogen Maser

Frequency stability of a Hydrogen maser clock

Log

(y(

))

Log (), seconds-3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0

1 Day 1 Month

-9

-10

-11

-12

-13

-14

-15

-16Hydrogen maser

Rubidium

Quartz

Cesium

Frequency stability of atomic clocks

Hydrogen maser Metrology applications

1 2 3 n...

BIPM

n-1 “independent” measurements

n clocks

CENAM´s clock ensemble of the ETP-1

M2

2d Master Clock (Hydrogen Maser)

1

...

Master clock

2

x21

3

x31

n

xn1

x23=x21-x31

jjiiiiij xxxx ,12,11, ...

)(...)()( 1,1,11,21,11,11, jjiiii xxxxxx

)( 1,1

1

1,

1

1,

k

j

ikk

j

ikkk xxx

i j

Log

(y(

))

Log (), seconds0 | 2 3 4 5 6 7 8 9 7.0

1 Day1 Month

-9

-10

-11

-12

-13

-14

-15

-16

Time scale generation philosophy

Hydrogen Maser

Time scale algorithm

UTC

Time scale

[email protected]

+ 52 (442) 211 0543

Hydrogen atomic clocks

J. Mauricio López R.División de Tiempo y Frecuencia

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Hydrogen atomic clocks