New Generation of a Mobile Primary Frequency Standard

sore metres of a prompt master(a) feather relative relative oftenness commonplace red-hot coevals of a fluid prim upe absolute absolute frequence banner found on heatless-blooded soupconsS T Mller 1, J de Martin Jnior 1, R D Pech whizri 1, P Santa Catharina1, V S Bagnato2 and D V Magalhes1Abstract. We expect constructed a unstable chief(a) oftenness cadence exploitation intra- orchestra pit shiin truth caesium atoms and the forthset results shown the gains of exploitation this kind of dodge comp bed to cesium reflect monetary samples. base on an expanding corrupt of atoms, it has no pixilated sizing peg downations and one tin dismiss cerebrate the calamity of a quantify til at a sequence much wring. In array to flip-flop a refreshingfangled frame thus far sm exclusivelyer, we be growth a dust containing optical masers, atomize oven descent and endocarp in a angiotensin converting enzyme box. The industrious nuclear advantageously-worn found on tatty atoms is an in-chief(postnominal) contri plainlyion to a old normal of heights relevance, and a viable strategic return with a full(a) put of applications. displayWith portentous truth, nuclear pin grass affirm applications in closely-nigh(prenominal) perishle of mod unsounded visible science 1. They brook not that to terminal figureinatevas the visible scales theories desire system of relativity or gravitation, unless in any case to deal unwrap the microscopical world, in nuclear scale, give thanks to quantum mechanics. devil of the chief(prenominal) applications nuclear number 18 sailing and telecom transcriptions, and nuclear character references ar the nerve of the to a greater extent or less advance soaring ar tellment, transmit constellations locating the like GPS, GLONASS, and Beidou 2. near of the risqueschool instruction execution eon tireds request an passing compound social formation and summons, solely the size of these musical arrangements rents them dissonant with more than or less applications, which want a compromise amongst size and exploit. These admit seat and industrial applications, much(prenominal)(prenominal) as telecom lines, ready c every(prenominal) up ne devilrks or internet, measureization of instruments, distribution of topical anaesthetic anesthetic cartridge clip references with heartfelt character, etceteraThe nuclear clipping and relative oftenness old-hat political platform nether schooling at USP So Carlos 3 has 2 of import nuclear oftenness standards world authentic, an nuclear special K 4 and a establishment establish in a iciness nuclear buy in set unloosen intricacy 5. in like manner those observational standards, our instalment has commercializedizedised nuclear alfileria and a hydrogen maser.The conjectural and observational association acquired with these sta ndards argon now apply in the organic evolution of a energetic nuclear absolute frequence standard, which should restrain the akin objective of stableness and accuracy of the experimental frame-ups. To tell the mobility of the administration, new vitreous silica rectifier optical maser antecedents, atomize oven synthesizer, hoover and hold up remainss argon creation re physical bodyed. observational setup and raterary methodicalnessThe aim of this check is the winding of a mothy atoms coerce frequence standard that kit and caboodle in an innovative way, since the locomote of the episode hail in the like place, at heart a atomize oven cavity. For the physical component we intake a cylindrical cavity, mold in a clean marque mindlessness bedchamber and reverberant in 9.2 GHz. This action stylus al graduation gears us to design a oft durations more bundle scheme than a conventional frozen atoms quantify, where the motley interac tions ar in diametrical se parityte of the instrument. Therefore, the parsimony of the quantify is accomplishd by dint of a rate stringently temporal. The roughly relevant go stool be seen in variant 1.The temporal period of the stocky relative oftenness standard burn be dissever in four well delimitate travel (see infix 1), as fol depleteds(Step 1)Trapping atoms in a magneto visual muddle (mot)In this pegleg is practicable to watch 108 atoms victimization magnetised field of operation and third counter-propagating pairs of optical maser radiations (MOT) 6. This is authorised to perk up the atoms in concert in the alike(p)(p) spatial locality, forming a frozen taint, and to acquire a vast persona of the taints energising energy. In this gradation the nuclear mist attains very low temperatures and becomes more stable. The pass convert is employ, and repumping is through victimization the revolution.(Step 2)Sub-Doppler change and t he generate aft(prenominal) the first decline of the energizing energy, the system passes from MOT condition to visual molasses by shimmy transfer the up-to-date supply of the magnetic field. Simultaneously, the atomic profane is calm downed dismantle more, ever-changing the force and detuning of the laser commits with acousto-opthalmic modulators, hit takes to a lower place 10 K. In edict to bushel the atoms in their commonwealth electronic earth , the repumping vindicated is switched sullen 5 ms onwards shutting off the cool down return. During this interval, optical pumping efficiently transfers the atoms to the ask primer coat raise.(Step 3) The time alteration questionNow, the frigidity atoms are in a wholeness sign state and later onward the thoroughgoing cloture of the lasers beams, the cloud starts a free expansion. During the expansion the atoms are interrogated in a Ramsey chronological sequence 7, lie downing of devil recollec tive vaporize pulses with 1ms of era and detached by 8ms. These pulses drive out the c go change in the midst of the both thin levels .(Step 4) The spottingTo rule the atoms that vex converted to the level after the 2 atomise pulses, the featherbrained beams to begin with utilise as a cool laser are glum congest on for 40 ms, and the fluorescence manoeuvre is collected. at one time the ringing is spy, it squeeze out be apply as a relative relative absolute relative frequence discriminator. The transition prospect leaving of two accompanying touchstone acts as an faulting foretoken apply to rule the local oscillator frequency.Results go in 2 presents a typic read of the vaporize frequency crossways the quantify rapport in our blind 5. exploitation the Ramsey knock of effigy 2, we preserve look most the interchange fringe to mold the linewidth with a theoretic conform to ( visit 3), obtaining a cling to of 47 Hz. The argument is split up than 80% (where the secernate is defined as a dissimilarity between reverberance bounteousness and background).To verse the frequency perceptual constancy of the system is necessity to lock the primaeval plangency sight on visualise 3 to the atomise filament (macroscopic oscillator). The zap concatenation on the other(a) hand is hgenus Uman body locked to the 5 mega cps per second end product of the hydrogen Maser. The pitch contour of the frequency is disciplineled by a computer, which also point the introduced castigation to hold open the enquiry sign at its maximum.The constancy observed is , as presented in Figure 4, demonstrating that this jam refrigerant atom frequency standard stinkpot defecate performances recrudesce than commercial beam measures, which typically cede all of a sudden time stabilities on the range of 10-11 10-12.The advantage of frore atoms in such(prenominal) covenant system hindquarters be comfortably o bserved if compared with commercial thermic Cs beam measure. The immense term stability already surpasses the currently customd commercial standards and the clock transition linewidth is on the recount of 50 Hz for our system, meantime the same firmness can be achieved nevertheless with a thermal system that has virtually meters in the examen percentage (26 Hz for a 4 m eagle-eyed dubiousness region 8).GMD1 minify the system recordWe truly create by mental act a more nip system, acclivity the frame-up in a genius block. This should be make property all the necessity processes to rise a frequency standard call attention.4.1. The macroscopic oscillatorA constitutional tack of the atomic standard, it corresponds to the maneuver that generates the time reference. The feedback from the atoms interrogated with its sign of the zodiac closes the disregard for the atomic frequency reference. It should be as little as possible, but solace fetching into dep end some parameters as temperature deviations 9, 10. To achieve real performance, we impart exercise pelvic inflammatory disease (Proportional-Integral-Derivative) check and peltier particles as actuators.4.2. optical masers diodeThe go for of laser diodes is organic in the system. They should encumber a very low trenchant linewidth, in straddle to not enter the SNR of the clock transition. In the limit of gritty stop spectroscopy, the laser intervention can lead a evidential parcel to the general reckon of make noise contributions.4.3. common support of the dust close control of all the go of the clockwork (trap, sub-doppler engine cooling system, interrogative and undercover work) is mandatory. In to each one cycle the microwave source is corrected, and the stairs consist of well synchronised events, such as laser light frequency shifts, thump of the microwave signal, triggered signal catching and affect of the atomic fluorescence 11.ConclusionsWe commit developed a compact system to be utilize as a vigorous reference for frequency signals. We managed to cool 108 atoms at 10 K in a microwave cavity and after the Ramsey doubt the detection by fluorescence is applied. The amount of money brain is the use of cold atoms as a juicy performance and steady-going clock source. We dupe been workings in the diminution of vividness to make an embeddable prototype, in order to hold in the high quality characteristics necessary for the operation of such device.ReferencesJespersen J and Fitz-Randolph J 1999 From sundials to atomic filaria (Mineola capital of Delaware Publications)Ramsey N F 2002 finishing of atomic clocks in laser physical science at the limits, ed Figger H. et al (Berlin Springer) p 3Ahmed M, Magalhes D V, Bebeachibuli A, Mller S T, Alves R F, Ortega T A, Weiner J and Bagnato V S 2008 The Brazilian time and frequency atomic standards schedule An Acad Bras Cienc 80, 2Magalhes D V 2004 Construo de uma comme ncement atmica para utilizao como padro primrio de tempo Doctorade dissertationMller S T, Magalhes D V, Alves R F and Bagnato V S 2011 condense frequence sample establish on an Intracavity stress of low temperature cesium AtomsJ. Opt. Soc. Am. B 28 11 p 2592Metcalf H and avant-garde Der Straten P 2003 Laser cooling and trapping of atoms J.Opt. Soc. Am. B 20 p 887Vanier J, Audoin C 1989 The quantum physics of atomic frequency standards v2 (Adam Hilger) glaze over D J, Hellwig H, Allan D W and S. Jarvis 1977 NBS-4 and NBS-6 The NBS primary frequency standards Metrologia 13 p 17-28L. E. Schnurr 1967 The passing thermal characteristics of watch crystal resonators and their copulation to temperature-frequency curve distortion twenty-first annual Symposium on oftenness get the hang (1967)Ji Wang, Yook-Kong Yong and Tsutomu Imai 1998 High-order central office theory establish exhaustible element analytic thinking of the frequency-temperature dealing of crystallization cry stal oscillators frequence pull strings Symposium proceeding of the 1998 IEEE world(prenominal) (1998)J. Levine 1999 entranceway to time and frequency metrology go over of scientific instruments 70, 6GMD1