표제지
목차
보고서 요약서 3
요약문 4
SUMMARY 6
제1장 서론 12
제2장 원자분수 1차 주파수표준기 개발 13
제1절 서론 13
제2절 세슘 원자분수시계 설계 및 제작 13
1. 마이크로파 공진기 제작 및 튜닝 13
2. 정자장 (C-filed) 솔레노이드 제작 15
3. 자유비행영역(free flight area) 튜브 및 진공펌프 조립 16
4. 물리부 조립 및 고진공 달성 17
5. 마이크로파 주파수 합성기 18
6. Ramsey 신호 관측 및 주파수 안정화 20
제3절 불확도 평가 21
1. 2차 Zeeman 효과 21
2. 공진기 당김 (Cavity pulling)과 흑체복사 (Blackbody radiation) 23
3. 냉각원자 충돌 (cold collision)에 의한 주파수 이동 25
4. 공진기 위상불균일 (DCP)에 의한 불확도 26
5. 기타 효과 및 불확도 결과 30
제3장 이터븀 광격자 시계 개발 31
제1절 서론 31
제2절 광격자 시계 개발 및 불확도 평가 32
1. TAI를 이용한 절대주파수 측정 계산 방법 연구 32
2. 이터븀 manipulation laser 시스템 33
3. 초미세 선폭의 시계레이저 개발 34
4. 이터븀 광격자 시계 불확도 평가 (2013 년) 44
제3절 광격자시계 2호기 개발 61
가. 진공 챔버 구성 61
나. 원자빔 deflector 62
다. An idea for moving optical lattice 63
라. Test of cryogenic spectroscopy chamber & cooler 64
마. 399 nm 레이저 66
바. 759 nm 레이저 67
제4절 광격자시계 1 호기 시스템 개선 68
제5절 GPS 위성을 이용한 광시계 주파수 국제 비교 75
제6절 결론 76
제4장 위성이용 국제시각 비교 77
제1절 GNSS 이용 시각비교 77
1. 상시 시각비교 및 유지 77
2. GPS 반송파 이용 수신기 평가 78
3. GLONA SS 이용 시각비교 85
제2절 통신위성 이용 양방향 시각비교(TWSTFT) 89
1. TW STFT 이용 시각비교 89
2. TW STFT 반송파 이용 기술 91
제3절 첨단동 시각비교 실험실 구축 102
1. 안테나 좌표 측정 102
2. 케이블 포설 및 지연 측정 104
3. GNSS 시각비교 수신기 이전 및 안정화 104
제4절 표준주파수국 운용 110
1. HLA 운용 이력 110
2. 표준주파수 수신율 향상 연구 110
3. HLA 기준시 동기 112
제5장 광파이버 이용 초정밀 시각비교 기술 개발 115
제1절 서론 115
제2절 RF 전송 115
1. 광섬유에 의한 잡음 115
2. 광학부 구성 116
3. 잡음 보상회로 118
4. 단기 및 장기 안정도 개선을 위한 노력 119
5. 실험실 내외에서의 시연 120
제3절 시각 전송 121
1. 시각 전송을 위한 시스템 및 보상 시스템 개발 121
2. 실험실 내외에서의 전송 실험 122
제4절 광주파수 전송 123
1. 설계 123
2. 제작 125
3. 전송 시연 결과 130
제5절 결론 135
제6장 원자중력계 개발 136
제1절 서론 136
1. 필요성 136
2. 연구개발의 기술개요 136
3. 국내외 기술 개발 현황 136
4. 연구 목표 136
제2절 레이저 실험장치 구성 및 실험 결과 (2013년) 137
1. 레이저 실험 137
2. 실험결과 143
제3절 레이저 실험장치 재구성 및 실험결과 (2014년) 146
1. 레이저 실험장치 재구성 146
2. 실험 결과 151
제4절 결론 159
Table 2-1. Current total uncertainty budget of KRISS-F1. 30
Table 3-1. Lattice induced frequency shift 51
Table 3-2. Total systematic uncertainty budget for 171Yb optical lattice clock in 2013 52
Table 3-3. Temperature variation inside vacuum chamber & AH-coil mount dependingon coil current of AH-coil. 70
Table 4-1. Summary of the GPS receivers for the time transfer at KRISS. 77
Table 4-2. Summary of the zero base-line experiment results. 80
Table 4-3. Summary of 10 times repeated measurement result. 84
Table 4-4. Parameters of phase measurement 93
Table 4-5. Frequency information for satellitecommunication 98
Table 4-6. Results of measurement 101
Table 4-7. Coordinates of antennas at Building 313 103
Table 4-8. Time delays of 4033A distribution amplifier(SN: 138536) 109
Table 4-9. Time delays of PD10 distribution amplifier(SN: 14AR20-08) 109
Table 4-10. Measurement results from KRISS to Geoje-do at each spots. 112
Table 4-11. Coordinates of GPS TT receiver at HLA 113
Table 5-1. Parts for Er-doped fiber 125
Table 5-2. Spec. of the laser. 127
Table 5-3. Types of frequency data for several frequency counters 133
Table 5-4. Current status of ability of time and frequency transfer via the optical fiber. 135
Table 6-1. Contents and scope about the developemet of an atomic gravimeter in 1st stage of WCL. 137
Fig. 2-1. Microwave cavity parts (left) and cavity body being polished precisely(right). 14
Fig. 2-2. Microwave resonance signal for Rb and Cs microwave cavities. 15
Fig. 2-3. 3D Model of solenoid bobbin (left) and C-field solenoid (right). 16
Fig. 2-4. 3D Model of flight tube and (left) and assembled flight tube (right). 17
Fig. 2-5. 3D Model of flight physics package (a) and assembled physics package without (b) and with magnetic shields (c). 18
Fig. 2-6. (a) Schematic diagram of microwave synthesis for Cs fountain clock, (b) phase/amplitude balanced 1×4 microwave distributer. 20
Fig. 2-7. (a) Ramsey fringes for clock transition with optical molasses operation. (b) Allan deviation of the frequency difference between the fountain and hydrogen maser H-4. 21
Fig. 2-8. (a) The time average of the magnetic field for different launching heights (b) Uncertainty of 2nd order Zeeman shift from spatial inhomogeneity for different launching heights.... 23
Fig. 2-9. Schematic diagram of measurement of cavity resonance with AC Zeeman effect. 25
Fig. 2-10. (a) Cavity resonance signal, (b) cavity resonance frequency vs. cavity temperature. 25
Fig. 2-11. Instability of high and low density ratio. 26
Fig. 2-12. m=1 DCP shift measured by feeding alternately from south and north (a) and east and west (b) for three different microwave amplitude b as a function of vertical tilt. 27
Fig. 2-13. Integrated time-of-flight signal in detection chamber as a function of tilt angle. 28
Fig. 2-14. Relative frequency offset against hydrogen maser H-4 for balanced feeds (both south and north feeds) as a function of tilt angle. 28
Fig. 2-15. Measured (circles) and calculated (lines) change in transition probability 29
Fig. 3-1. KRISS supercavity for the Yb lattice clock laser. (a) support position of the supercavity (x, z) (b) cut-out size of the supercavity. 36
Fig. 3-2. FEM calculation result of the vibration sensitivity on the support position and the support area (a) for the old KRISS cavity and (b) for the new KRISS cavity. 36
Fig. 3-3. (a) shaker for the vibration sensitivity measurement (b) viton pads for the cavity support. 37
Fig. 3-4. vacuum chamber for the vibration sensitivity measurement. 37
Fig. 3-5. (a) vertical, (c) transverse, and (e) longitudinal acceleration of the shaker, and (b), (d), (f) their respective cross-coupling to other direction. 39
Fig. 3-6. Experimental (marks with dotted lines) and theoretical (solid lines) result of the vibration sensitivity as functions of z for x=22 mm and c=18.45 mm. (a) fixed support model,... 39
Fig. 3-7. Experimental (marks with dotted lines) and theoretical (solid lines) result of the vibration sensitivity as functions of z for x=22 mm and c=19.45 mm. (a) fixed support model,... 40
Fig. 3-8. (a) reproducibility of vertical sensitivity measurement, (b) optical beat note between two independent clock laser after the improvement. 40
Fig. 3-9. Fourier-transform-limited Yb clock transition spectrum for the probe time of (a) 20 ms and (b) 80 ms. 41
Fig. 3-10. Experimental result of the vibration sensitivity as functions of z for x=22 mm and c=18.45 mm. (a) for longitudinal vibration, (b) for transverse vibration. 41
Fig. 3-11. Experimental result of the vibration sensitivity as functions of z for x=22 mm and c=19.45 mm. (a) for longitudinal vibration, (b) for transverse vibration. 41
Fig. 3-12. (a) reproducibility of transverse sensitivity measurement, (b) reproducibility of longitudinal sensitivity measurement. 42
Fig. 3-13. Experimental setup for the clock laser using second harmonic generation. 42
Fig. 3-14. optical spectrum without injection laser (black) and with injection laser (red). 43
Fig. 3-15. (a) 1156 nm amplifier output power as a function of the pump current without injection laser (red) and with injection laser (black), (b) optical spectrum of the amplified output... 43
Fig. 3-16. (a) phase matching temperature of the waveguide-PPLN for second harmonic generation, (b) output power of the second harmonic generation as a function of the IR input power. 43
Fig. 3-17. Scheme of optical pumping for Spin polarization of 171Yb atom in optical lattice 45
Fig. 3-18. Optical pumping for Spin polarization of 171Yb atom in optical lattice. 45
Fig. 3-19. Clock transition signal from spin-polarized 171Yb atom in optical lattice. 45
Fig. 3-20. (Top) Schematic diagram of the lattice drop method (Bottom) Estimated blue-sideband spectrum 47
Fig. 3-21. (LEFT) Sideband spectrum of the 200Er optical lattice. The red dashed line depicts the sideband spectrum at T = 4.9 μK. The blue solid line indicates the sideband spectrum after the... 47
Fig. 3-22. Energy level diagram 48
Fig. 3-23. Collisional frequency shift as a function of pulse area. 49
Fig. 3-24. (LEFT) Allan deviation of the measurement of the collisional frequency shift by the interlacing method (Right) Measured collisional frequency shi 50
Fig. 3-25. (LEFT) Frequency shift as a function of frequency of the optical lattice laser (Right) Magic frequency comparison with NIST’s reported one. 50
Fig. 3-26. Before(left) and after(after) of installation of additional MOT coil 51
Fig. 3-27. Zeeman splitting of clock transition (left), and Allan deviation of splitting(right). 52
Fig. 3-28. Chamber designation 62
Fig. 3-29. Atomic beam generator 62
Fig. 3-30. Atomic beam deflector design. 63
Fig. 3-31. Atomic beam deflector 63
Fig. 3-32. An idea for moving optical lattice to use the laser power efficiently 64
Fig. 3-33. Cryogenic cooler swing machine (left) and a copper test rod for measuring of temperature gradient of cryogenic chamber (right). 65
Fig. 3-34. Simulation of temperature gradient cryogenic rod in vacuum chamber (left) and experiment result (right). 66
Fig. 3-35. Compact cryogenic cooler (left) and splitted type cryogenic cooler (right). 66
Fig. 3-36. TA-SHG 399 nm Laser system. 67
Fig. 3-37. Tapered amplifier system for 759 nm laser. 68
Fig. 3-38. Atomic beam direction adjuster. 69
Fig. 3-39. Atomic beam nozzles : old design(left) & new design(newdesign) 69
Fig. 3-40. A radiometer used for temperature measurement (up-left). Temperature distribution outside of main chamber measured by radiometer (up-right). Temperature distribution inside of... 71
Fig. 3-41. Anti-Helmholtz(AH) coil mount with cooler water jacket (left). Assembly of AH coil mount and main vacuum chamber (Right) ; about 10 mm spaced between them. 72
Fig. 3-42. Temperature distribution inner surface of Zeeman slower depending on coil current (left). Zeeman slower’s hole viewed by atoms in optical lattice (Right). 73
Fig. 3-43. 1.33“ sapphire viewport and heater for Zeeman slowing laser entrance. 73
Fig. 3-44. Configuration of alignment for MOT laser, lattice laser, slowing laser, atomic beam, AH coils. 74
Fig. 3-45. A specially coated window for high transmission for 759 nm (left), and indium seal mount assembly (right). 75
Fig. 4-1. Time transfer receivers maintained at center for time and frequency. 77
Fig. 4-2. Unexpected jump of Z12T(3013) receiver 78
Fig. 4-3. Elevation and azimuth of the day of Z12T(3013) jump 78
Fig. 4-4. Block diagram of the zero base line experiment. 80
Fig. 4-5. Measurement results of the impact of the RF signal level variation on the performance. 81
Fig. 4-6. Block diagram of the short base line experiment. 82
Fig. 4-7. Compensation of the difference between two reference Cesium clocks. 82
Fig. 4-8. Conceptional block diagram of constructing UTC(KRIS) supplementary system at the new laboratory. 83
Fig. 4-9. Example of the repeated measurement result of Z12T(0201). 84
Fig. 4-10. A setup window of receiver control program. 86
Fig. 4-11. Observation data produced by a PolaRx3e receiver. 87
Fig. 4-12. GPS navigation data produced by a PolaRx3e receiver 87
Fig. 4-13. GLONASS navigation data produced by a PolaRx3e receiver 88
Fig. 4-14. Time comparisons among the receiver type and GPS and GLONASS. 88
Fig. 4-15. Time comparison result between KRISS and NICT without bandpass filter. 89
Fig. 4-16. Test of downlink(10.99 GHz) BPF filter 90
Fig. 4-17. Tracking the beacon signal of GE23 90
Fig. 4-18. Concept of TWCP 92
Fig. 4-19. Schematic diagram of ground stations 100
Fig. 4-20. Structure of receiver correlator 100
Fig. 4-21. Result of time difference between NICT and PTB by TWCP 102
Fig. 4-22. Structure of antenna frame (left: top view, right: front view) 103
Fig. 4-23. Cable delays and connector types of antennas and receivers 104
Fig. 4-24. Time difference between Z12T(3103) and Z12T(0201) (left side) and its residual (right side) by P-code 105
Fig. 4-25. Time difference between Z12T(3103) and Z12T(0201) (left side) and its residual (right side) by carrier phase 105
Fig. 4-26. C/A and P codes of GPS and GLONASS with ion free. 106
Fig. 4-27. Comparison between Z12T(3103) and TTS4 106
Fig. 4-28. Block diagram of estimation for TTS4 and PolaRx3e receivers 107
Fig. 4-29. GPS comparison between TTS4 and PolaRx3e 107
Fig. 4-30. GLONASS comparison between TTS4 and PolaRx3e 108
Fig. 4-31. P3 comparison of GPS and GLONASS by using TTS4 and PolaRx3e 108
Fig. 4-32. Hookup diagram and delays between UTC(KRIS) and each time transfer equipment 110
Fig. 4-33. Field measurement spots along the Daejeon-Tongyeong expressway. 111
Fig. 4-34. Monitor display of field measurement at Geoje-do where is located at 195 km of LOS from HLA station. 112
Fig. 4-35. Comparison between Z12T(3013) and PolaRx3e after the calibration of PolaRx3e receiver 113
Fig. 4-36. Drift rate of Cs 5071 at HLA 114
Fig. 5-1. (left) Cyoptics E2560 10Gb/s EML module (right) ILX LDM-4983 13-pin butterfly mount 117
Fig. 5-2. Setup for characterizing EML 117
Fig. 5-3. Allan deviation and phase noise of EML for different RF frequencies 118
Fig. 5-4. Noise cancellation RF circuit diagram 118
Fig. 5-5. servo PI circuit 119
Fig. 5-6. Allan deviation of 1GHz residual noise without temperature stabilization (blue open squares) and with temperature stabilization (green filled squares) 119
Fig. 5-7. Photo image of the noise cancellation RF circuit. at the local site (top) and at the remote site(bottom) 120
Fig. 5-8. Temperature stability at the local and the remote site circuit plates. 120
Fig. 5-9. Frequency stability for various fiber links. 121
Fig. 5-10. Time transfer system. TIC:time interval counter 122
Fig. 5-11. Daily variation of the delay time at the remote site (red or grey) and the delay time estimated from the reflected signal (black) for 23km fiber spool. Bottom curves in both plots... 123
Fig. 5-12. Daily variation of the delay time at the remote site (red or grey) and the delay time estimated from the reflected signal (black) for 2.4km fiber underground.. Bottom curves in... 123
Fig. 5-13. Schematic diagram for the optical frequency transfer and the noise cancellation system. 124
Fig. 5-14. Bi-directional EDFA 125
Fig. 5-15. EDFA gain for 55 μW input power 126
Fig. 5-16. recirculating delayed self-heterodyne setup 128
Fig. 5-17. Beat spectrum from RDSH setup 128
Fig. 5-18. Interferometer setup 128
Fig. 5-19. Digital PLL circuit diagram 129
Fig. 5-20. Digital PLL photo image 130
Fig. 5-21. Measured out-of-loop phase noise 131
Fig. 5-22. Window functions for different Allan deviations 132
Fig. 5-23. ADEV 134
Fig. 5-24. Λ-ADEV 134
Fig. 5-25. M-ADEV using 5125A and 53230A 134
Fig. 5-26. Frequency stability for All kinds of ADEV 134
Fig. 6-1. Concept of laser system for an atomic gravimeter. 138
Fig. 6-2. Sysmetic diagram of laser module. 139
Fig. 6-3. Energe levels of Rb87 and laser frequencies required for our atomic gravimeter. 139
Fig. 6-4. Ficture (a) and systematic diagram (b) of our laser system. 140
Fig. 6-5. Electronic scheme for the control of laser frequecies. 140
Fig. 6-6. PLDRO and phase noises of the phase-locked laser. 141
Fig. 6-7. Schematic diagram of the sequence control system. 142
Fig. 6-8. Block diagram of signanl generation and data acquisition. 142
Fig. 6-9. Raman spectrum of free-falling Rb 87 atom cloud. 143
Fig. 6-10. Raman transition of Rb87 atoms in F=1, mf=0 state 145
Fig. 6-11. Rabi oscillatios in tapered amplifiter(TA) current 1700ms (a) and 1300mA (b). 145
Fig. 6-12. Specta of Raman laser (a) and ratio of lasing intensity to ASE (b) versus TA injection current. 146
Fig. 6-13. Systematic diagram of our laser system. 147
Fig. 6-14. Energe levels of Rb87 and laser frequencies required in our atomic gravimeter 148
Fig. 6-15. Photograph of our laser sytem. 149
Fig. 6-16. Control modules of laser frequencies. 149
Fig. 6-17. Electronic scheme for the control of laser frequecies. 150
Fig. 6-18. Schematic diagram of the sequence control system. 151
Fig. 6-19. Timing sequencies of lasers and coil currents for measuring Rabi or Ramsey signals 152
Fig. 6-20. Rabi (a) and Ramsey signals (b) of free-falling atomic clouds. 153
Fig. 6-21. Timing sequecies of lasers and coil currents for measuring Rabi and MG interference signals. 154
Fig. 6-22. Rabi (a) and MG interference signal(b) obtained by using counter-propagating Raman laser. 155
Fig. 6-23. MG interference singnals vs pulse interval T. 155
Fig. 6-24. Zeeman shifts in the various positions of interference part of vacume chamber are measured by controling delay times of Raman pulse from the trigger signal. 156
Fig. 6-25. Second-order zeeman shifts vs various positions. 157
Fig. 6-26. MG interference singals (a) and fitting curves (b) as function of interval time T after compensation of the phase induced by 2nd odrer zeeman shift. 158
Fig. 6-27. Mignectic shield. 158