The 4th Yamada Symposium on Advanced Photons and Science Evolution 2010 APSE 2010 2010.06.14RIKEN Nishina Center for Accelerator-Based ScienceYukari MatsuoAdvanced atomic photon spectroscopy

Outline(1) Advanced atomic photon spectroscopy- Atomic laser spectroscopy - High precision spectroscopy for fundamental physics nuclear physics

(2) Atomic photon spectroscopy in condensed helium- Characteristic of atoms in superfluid helium (He II)- Precision laser spectroscopy of atoms in He II

(3) Application of precision laser spectroscopy to atoms with unstable nuclei - Novel nuclear laser spectroscopy of RI atoms in He II : OROCHI

(4) Summary

Atomic spectroscopyOptical atomic spectra reflect structure of atoms and nuclei.

Laser spectroscopyconventional laser spectroscopic methods easily reach to an accuracy of 10-8 10-9Development of laser has dramatically improved measurement techniques

For the higher accuracyIt is necessary to reduce the factors to determine linewidth and uncertainty

State-of-the-art experiment

State-of-the-art experiment

For the higher accuracyIt is necessary to reduce the factors to determine linewidth and uncertaintyDoppler widthCollisional widthNatural widthFrequency uncertainty~ 10-19

Atomic laser spectroscopy and the study of nucleialkaline like atomsPrecision measurement of atomic sublevel structures can provide valuable information on nuclear structure because nuclear spins and moments are fundamental physical quantities of nuclei Nuclear laser spectroscopy

Brief summaryAdvanced atomic photon spectroscopyand so forth CPT violation?Search for EDMThe ultimate precision spectroscopic measurements can be regarded as a powerful tool to approach the fundamental physics and cosmology, including particle and nuclear physics

Outline(1) Advanced atomic photon spectroscopy- Atomic laser spectroscopy - High precision spectroscopy for fundamental physics nuclear physics

(2) Atomic photon spectroscopy in condensed helium- Characteristic of atoms in superfluid helium (He II)- Precision laser spectroscopy of atoms in He II

(3) Application of precision laser spectroscopy to atoms with unstable nuclei - Novel nuclear laser spectroscopy of RI atoms in He II : OROCHI

(4) Summary

Low temperature, trapping capability of He II would be a good environment for spectroscopyLarge collisional broadening by surrounding He atoms will be an obstacle for precision spectroscopyWhat is the behavior of atoms in superfulid helium ?

Impurities in superfluid heliumElectron bubbleSnowballAtomic bubbleOptical transition spectrum is observed in 1990Laser spectroscopy started in 1980sOptical emission is not observed~17 ~several 1s-1p transition; 5~7mm1s1p2pUV ~ visible ~ NIR region

Optical spectra (atomic-bubble model)broad,large blue-shiftsharp,small shiftsimple model describes spectra well

Typical LIF spectra of atoms/ions in He IIwavelength (nm)Intensity (arb.unit)absorption (broad)line positionin vacuumemission (sharp)133Cs in He IICs D1 spectrumenergy level in vacuumKyoto groupTakahashi, et.al., 1993

Atoms and ions observed using laser spectroscopic method in He II

Outline(1) Advanced atomic photon spectroscopy- Atomic laser spectroscopy - High precision spectroscopy for fundamental physics nuclear physics

(2) Atomic photon spectroscopy in condensed helium- Characteristic of atoms in superfluid helium (He II)- Precision laser spectroscopy of atoms in He II

(3) Application of precision laser spectroscopy to atoms with unstable nuclei - Novel nuclear laser spectroscopy of RI atoms in He II : OROCHI

(4) Summary

But, how one can do precision laser spectroscopy in superfluid helium?Combination of optical pumping & double resonance is a way out of the difficulty

Using superfluid helium as a matrix HFS transition is observable using laser microwave double resonancefor CsTakahashi, et.al. Z. Phys. B 98 (1995) 391Multiple HFS levels can be optical pumped simultaneously large shift, broad spectrumcould be an obstacleintroducing atoms quietly was difficult...

Experimental setupIn 2000s

Double resonance spectroscopyMearsurement of atomic sublevel structures

Optical Pumping in He II Polarization ~90 %(Cs) ~50 %(Rb) Pumping time : ~1 ms (Cs & Rb)

Zeeman splitting measurement

Hyperfine splitting measurement

Hyperfine anomalyT. Furukawa, Doctoral thesis, Osaka Univ. (2007)T. Furukawa, et. al., Hyp. Int., 196, 191 (2010). for the 1st order hyperfine anomaly (Bohr-Weisskopf effect)

Hyperfine anomaly85D 87This work (from AHeII) 0.330 (5) %literature value 0.3474 %difference5(1) %

Atomic hyperfine structure in He II 1% increasementA=mI/IJ is different in He IIAtoms are pressurized by Hevalence electron orbital is affected HeII (GHz)vacuum (GHz)Hyperfine coupling constatns HeII/vacuum ratio133CsRb85872.31283(3)2.298157941.01700(3)3.43514(5)3.417341311.011910921.00638(1)1.00503(3)1.00521(1)Changes in CsRbPreliminary

Further developmentoptical pumping of atoms other than alkalisIn vacuumIn He IINeeds many lasersA single laser can excite all the atomic levelsAbsorption spectra are broadenedIt is plausible to optical pump atoms with complicated energy levels?wavelength do not need to be exactly tunedspin polarization is generated if pumping rate is larger than the relaxation ratepulsed laser can be used as well as cw lasersTaking advantage of characteristic feature of He II freedom to choose lasers Group 11 elements (Ag, Au) are spin polarized

Outline(1) Advanced atomic photon spectroscopy- Atomic laser spectroscopy - High precision spectroscopy for fundamental physics nuclear physics

(2) Atomic photon spectroscopy in condensed helium- Characteristic of atoms in superfluid helium (He II)- Precision laser spectroscopy of atoms in He II

(3) Application of precision laser spectroscopy to atoms with unstable nuclei - Novel nuclear laser spectroscopy of RI atoms in He II : OROCHI

(4) Summary

Laser spectroscopy of atoms in He II for the study of unstable nuclei : OROCHIOptical RI-atom Observation in Condensed Helium as Ion-catcherAdvantageous for the study of low yield and short-lived unstable nuclei

Advantages of using He II for the limited number of accelerator generated nucleiAdvantages of laser spectroscopyAdvantages of He II matrix+

the first laser experiment @ RIKEN RIPS beam lineinject high speed ion beam, and observe laser induced fluorescence from the neutralized atomsD1D2F1F2F3F2-slitF1-slit87Rb primary beamHe IIRI beam injectioncryostatLarge solid angle optical detection systemvariable Al degrader,plasticoptical pump & laser RF/MW double resonance84,86Rb secondary beamtarget1st experiment Towards beam-line experiment2nd experiment Laser

87Rb beamLiq. He dewerHe II cryostatPumping system for He II Optical detection systemLaserBeam-line experiment setup

87Rb beamLiq. He dewerHe II cryostatPumping system for He II Optical detection systemLaserBeam-line experiment setup

Summary The ultimate precision spectroscopic measurements can be a powerful tool to approach the fundamental physics and cosmology, including particle and nuclear physics. Precision spectroscopy of atoms in superfluid helium is possible by using the combination of optical pumping and double resonance spectroscopy. We have successfully demonstrated that superfluid helium provides a new environment of optical spectroscopy through the measurement of long spin relaxation time and the precision laser spectroscopy of Rb and Cs. Laser spectroscopy of atoms in superfluid helium will be a powerful technique to study nuclear structure of short-lived radioisotopes (RIs) generated at accelerator facilities; OROCHI (Optical RI-atom Observation in Condensed Helium as Ion-catcher) project.

Spokesperson: Takeshi Furukawa (Tokyo Institute of Technology), Yukari Matsuo (RIKEN)

RIKEN; H.Ueno, N.Aoi, A.Yoshimi, K. Yoneda, M.Takechi, Y.Togano, Y. Ichikawa, S.Takeuchi, S.Nishimura, M.Nishimura, T. Kobayashi, M.Wada, T.Sonoda, T.Motobayashi Tokyo Tech.; K.Asahi, Y.Kondo.. CYRIC, Tohoku U.; A. Sasaki, T.Wakui, H.Ouchi, S.Izumi, T. Shinozuka Osaka U.; T. Shimoda, A.OdaharaTokyo U. Agr. Tech.: A. Hatakeyama Meiji U.: Y. Matsuura, Y. Kato, Y. Yamaguchi, K. ImamuraAoyama-gakuin U.: A.TakamineCNS, U.Tokyo; S.Kubono, Y. Ohshiro

Acknowledgement to OROCHI collaborators

Thank you for your attention !