Fast beam laser

COLL INEAR FAST-BEAM LASER SPECTROSCOPY... 

As mentioned above, the radon and radium sequences have been investigated by collinear fast-beam laser spectroscopy, whereas in francium all three atomic-beam methods, ABMR, atomic-beam laser spectroscopy and collinear laser spectroscopy, have contributed. 

Abstract. Laser spectroscopy of hydrogen-like and helium-like ions is reviewed. Emphasis is on the fast-beam laser resonance technique, measurements in moderate-/ ions which provide tests of relativistic and quantum-electrodynamic atomic theory, and future experimental directions. 

Fig. 1. (a) Energy levels of F8+ relevant to the measurement of the n = 2 Lamb shift (b) Schematic illustrating the fast-beam laser resonance technique... 

Abstract. Using Doppler-tuned fast-beam laser spectroscopy the ls2p 3Po - 3Pi fine structure interval in 24Mg10+ has been measured to be 833.133(15) cm-1. The calibration procedure used the intercombination ls2s 1So - ls2p 3Pi transition in 14N5+. The result tests quantum-electrodynamic and relativistic corrections to high precision calculations, which will be used to obtain a new value for the fine structure constant from the fine structure of helium. 

For various ions the 2S /2 — 2P1/2 and 2,S - /2 — 2P3/2 transitions match the wavelengths of certain efficient lasers enabling spectroscopy with the fast-beam laser-resonance technique [9], The most precise measurement of this type, achieved after considerable experimental development, was of the 2Si/2 — 2P3/2 transition in P14+ [10], where an uncertainty equivalent to 0.15% of the 2Si/2 — 2Pi/2 interval was obtained. A high-power pulsed dye-laser producing intensities of over 10 MW/cm-2, but with a duty cycle of about 10-5, was required to obtain a good signal-to-background ratio. 

Abstract. Using Doppler-tuned fast-beam laser spectroscopy the ls2p Po - Pi fine structure interval in has been measured to be 833.133(15) cm . The cah-... 

Fig. 5.47. Simplified scheme of the experimental set-up for detector of Sr by collinear fast beam laser excitation and resonance ionization detection.

The combination of collinear fast-beam laser spectroscopy and P-RADOP (radiation-detected optical pumping) has been used to measure nuclear spins and moments of neutron-rich isotopes of the light alkali elements jLi [72-74] and Na [75]. Here, the optically pumped fast atomic beam is implanted into a single crystal placed in a static magnetic field. The NMR signal is destroying the nuclear polarization detected by measuring the p-decay asymmetry. 

The nuclear spins and moments of the strongly deformed rare-earth nuclides have been discussed in detail previously within die Nilsson model in connection with the ABMR experiments mentioned above [79]. The addition of the data fiom coUinear fast-beam laser spectroscopy [48, 50, 71], the new reference values on spectroscopic quadrupole moments from muonic and pionic hfs [1], and the refined calculations within the partice-rotor model, including a number of orbitals close to the Fermi surface, have however resulted in a more complete picture and a better understanding of tiie nuclear single-particle stmcture in this region. 

Among the odd-proton rare-earths, the element europium (Z = 63) has been thoroughly investigated at ISOLDE by coUinear fast-beam laser spectroscopy in the range Eu [47]. The ABMR works include spin measurements in ... 

With laser beams, the effect can be observed in absorption. This is the basis for collinear fast-beam laser spectroscopy. Among the Doppler-free techniques (described in Part A, Chapter 15 by W. Demtroder) it is the only one using linear absorption without velocity selection as in collimated atomic beams. 

The crucial parameter for the resolution in fast-beam laser experiments is the kinetic energy spread of the ions. For low-energy beams ( < 100 keV) it is determined by the ion source and typically of the order 1 eV, if the acceleration voltage is well stabilized. To meet this value, plasma sources have to be operated with special care with regard to the pressure and potential distribution within the source. Surface ionization sources may almost reach the thermal energy spread of fcT, but this requires very homogeneous and clean surfaces. 

Figmre 5. Experimental setup for fast-beam laser-rf double resonance spectroscopy. (From Ref. 

Table 1. Measurements on Radioactive Nuclides by Collinear Fast-Beam Laser Spectroscopy... 

Figure 10. Essential components of the ISOLDE setup for collinear fast-beam laser spectroscopy. The postacceleration and scanning...

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