GB875242A - Atomic stabilized frequency source - Google Patents
Atomic stabilized frequency sourceInfo
- Publication number
- GB875242A GB875242A GB6027/59A GB602759A GB875242A GB 875242 A GB875242 A GB 875242A GB 6027/59 A GB6027/59 A GB 6027/59A GB 602759 A GB602759 A GB 602759A GB 875242 A GB875242 A GB 875242A
- Authority
- GB
- United Kingdom
- Prior art keywords
- resonance
- frequency
- generator
- vessel
- photo
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000003287 optical effect Effects 0.000 abstract 7
- 238000010521 absorption reaction Methods 0.000 abstract 6
- 230000007704 transition Effects 0.000 abstract 5
- 230000005855 radiation Effects 0.000 abstract 4
- 125000004429 atom Chemical group 0.000 abstract 3
- 239000007789 gas Substances 0.000 abstract 3
- 125000004436 sodium atom Chemical group 0.000 abstract 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 abstract 2
- 230000003595 spectral effect Effects 0.000 abstract 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 abstract 1
- 239000003513 alkali Substances 0.000 abstract 1
- 229910052786 argon Inorganic materials 0.000 abstract 1
- 239000002585 base Substances 0.000 abstract 1
- 230000001419 dependent effect Effects 0.000 abstract 1
- 230000000694 effects Effects 0.000 abstract 1
- 238000005086 pumping Methods 0.000 abstract 1
- 230000002441 reversible effect Effects 0.000 abstract 1
- 229910052708 sodium Inorganic materials 0.000 abstract 1
- 239000011734 sodium Substances 0.000 abstract 1
- 230000003313 weakening effect Effects 0.000 abstract 1
Classifications
-
- G—PHYSICS
- G04—HOROLOGY
- G04F—TIME-INTERVAL MEASURING
- G04F5/00—Apparatus for producing preselected time intervals for use as timing standards
- G04F5/14—Apparatus for producing preselected time intervals for use as timing standards using atomic clocks
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
- H03L7/00—Automatic control of frequency or phase; Synchronisation
- H03L7/26—Automatic control of frequency or phase; Synchronisation using energy levels of molecules, atoms, or subatomic particles as a frequency reference
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
Abstract
875,242. Automatic frequency control systems. VARIAN ASSOCIATES. Feb. 20, 1959 [Feb. 21, 1958], No. 6027/59. Class 40(5) [Also in Group XL(b) ] An optical absorption system, for example for use as a standard frequency source or "atomic clock" comprises a vessel containing alkali vapour which is placed in a magnetic field, a source of optical radiation arranged to effect optical pumping of the atoms of the vapour whereby they become aligned in said magnetic field, a source of radio frequency energy at the hyperfine resonance transition frequency of said atoms to produce such hyperfine transition of the atoms in the vessel and means for detecting the optical radiation after it has passed through the vessel, the detecting means serving to measure changes in the intensity of the radiation due to the absorption of energy therefrom at the hyperfine resonance. In Fig. 1, the absorption vessel 11 contains metallic sodium in equilibrium with its vapour and argon acting as a buffer gas, and is positioned in a cavity resonator 13 contained in an oven kept at 120‹-145‹C. Lamp 21 forms the source of optical radiation and the aligning magnetic field H o is the earth's field, a radio frequency generator 29 being coupled to the cavity resonator to provide a radio frequency magnetic field and thereby induce the hyperfine transitions of the sodium atoms. A resonance of the sodium atoms occurs and results in a weakening of the light detected by a photo-cell 26, the output from which is amplified and displayed on an oscilloscope 28. The radio frequency of generator 29 is frequency modulated by a modulator 32 which also provides the time base for the oscilloscope so that the point of maximum hyperfine transition can be swept through periodically. The spectral frequency of the energy quanta separating the hyperfine levels is substantially constant and independent of the strength of (weak) field H o . A stabilized oscillator or "atomic clock" is described in Fig. 4 (not shown) in which a phase detector compares the output of the photo-cell and that of a sweep generator, the D.C. error output signal of the phase detector being dependent on the extent to which the resonance output signal from the absorption vessel is off maximum resonance, and tuning the radio frequency generator to maximum hyperfine resonance frequency, e.g. through a reversible D.C. motor. In order to compensate for any change in spectral frequency due to possible variations in H o , a second radio frequency generator 38 in addition to the one referred to with respect to Fig. 4 is provided in the embodiment of Fig. 5, the output of generator 38 being coupled to coils 39 in vessel 11 to induce a radio frequency field of the Larmor frequency of the sodium atoms. An additional sweep generator 41 coupled to coils 42 is provided to produce a modulation of H o and therefore a sweep through the Larmor frequency. Photo-cell 26 detects the optical absorption in vessel 11 due to both the hyperfine resonance and the Larmor frequency transitions and the output from amplifier 27 is fed to a second phase detector 43 the reference signal for which is obtained from sweep generator 41. The output of detector 43 is a D.C. error signal the sign of which depends on the side of maximum resonance on which the Larmor resonance signal is and the amplitude of which depends on the amount of resonance, and the output is fed to a bias coil 44 producing a correcting magnetic field for H o ; detector 37 and sweep generator 36 being used as before to adjust the radio frequency generator. The correcting information for the radio frequency generator 29 may be obtained without the use of frequency or phase modulation by varying the pressure of the buffer gas (Fig. 6). Absorption vessel 51 is separated into two parts 52, 53 having different buffer gas pressures (100 m.m. Hg, 90 m.m. Hg) two points of maximum resonance being therefore produced, which are detected by separate photo-cells 54, 55. The outputs from said cells are connected to a difference amplifier comprising a pair of triodes 57, 58, the potentials on the grids of said triodes varying with the light signals on the photo-cells, any difference in the light signals producing a D.C. output which tunes generator 29. In order to avoid errors due to arbitrary changes in light intensity on the photo-cell, two pairs of photo-cells are used in Fig. 7 (not shown) which are under continuous test by amplitude modulating the light from the optical source by a low amplitude signal, so that, if all four photocells are equal, meters connected thereto will read zero. Alternatively, one photo-cell only may be used which detects the light from each half vessel alternately.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US875242XA | 1958-02-21 | 1958-02-21 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB875242A true GB875242A (en) | 1961-08-16 |
Family
ID=22205685
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB6027/59A Expired GB875242A (en) | 1958-02-21 | 1959-02-20 | Atomic stabilized frequency source |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB875242A (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3158803A (en) * | 1962-02-21 | 1964-11-24 | Varian Associates | Apparatus for monitoring magnetic field gradients |
US3187251A (en) * | 1962-02-21 | 1965-06-01 | Varian Associates | Quantum oscillators |
US3242423A (en) * | 1962-01-10 | 1966-03-22 | Csf | Resonance cells for optical pumping |
US3256478A (en) * | 1963-12-26 | 1966-06-14 | Varian Associates | Optical pumping of hyperfine states by light pulsed at the zeeman frequency |
US3256500A (en) * | 1963-01-07 | 1966-06-14 | Varian Associates | Optical magnetometers |
GB2304185A (en) * | 1995-08-11 | 1997-03-12 | Fujitsu Ltd | Frequency variation compensated rubidium atom oscillator |
CN107068525A (en) * | 2017-05-08 | 2017-08-18 | 中国科学院武汉物理与数学研究所 | A kind of device for being used under vacuum environment produce Atomic Vapor |
CN112702060A (en) * | 2020-12-11 | 2021-04-23 | 兰州空间技术物理研究所 | Microwave amplitude control method for cesium atomic clock |
-
1959
- 1959-02-20 GB GB6027/59A patent/GB875242A/en not_active Expired
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3242423A (en) * | 1962-01-10 | 1966-03-22 | Csf | Resonance cells for optical pumping |
US3158803A (en) * | 1962-02-21 | 1964-11-24 | Varian Associates | Apparatus for monitoring magnetic field gradients |
US3187251A (en) * | 1962-02-21 | 1965-06-01 | Varian Associates | Quantum oscillators |
DE1289134B (en) * | 1962-02-21 | 1969-02-13 | Varian Associates | Vibration generator controlled by optical quantum transitions |
US3256500A (en) * | 1963-01-07 | 1966-06-14 | Varian Associates | Optical magnetometers |
US3256478A (en) * | 1963-12-26 | 1966-06-14 | Varian Associates | Optical pumping of hyperfine states by light pulsed at the zeeman frequency |
GB2304185A (en) * | 1995-08-11 | 1997-03-12 | Fujitsu Ltd | Frequency variation compensated rubidium atom oscillator |
US5712597A (en) * | 1995-08-11 | 1998-01-27 | Fujitsu Limited | Rubidium atom oscillator with temperature stabilized frequency output |
GB2304185B (en) * | 1995-08-11 | 1999-12-29 | Fujitsu Ltd | Rubidium atom oscillator for oscillating a microwave having a stable frequency |
CN107068525A (en) * | 2017-05-08 | 2017-08-18 | 中国科学院武汉物理与数学研究所 | A kind of device for being used under vacuum environment produce Atomic Vapor |
CN112702060A (en) * | 2020-12-11 | 2021-04-23 | 兰州空间技术物理研究所 | Microwave amplitude control method for cesium atomic clock |
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