A Single-Mode, Diode-Pumped Lma Laser To Probe The Spin Orientation Of Ensembles Of 3he And 4he

A diode-pumped Nd:Lanthanum Magnesium Hexaluminate laser was constructed which provides up to 15 mW of single-mode, tunable CW emission at 1083 nm. By appropriately polarizing the narrow-band laser emission (< 10 MHz), the laser can be used to determine the populations of the magnetic substates of the He ( 23S1) atoms. The laser is tuned to one of the absorption peaks of the helium metastable atom by tilting a thin (1 mm) solid, coated etalon placed inside the laser cavity and the absorption is measured. The relative absorption is used to determine the ensemble polarization ; the absolute absorption yields the metastable density

Argon Metastable-cadmium Dihalide Energy Transfer Collisions In A Flowing Afterglow

The energy dependence of dissociating collisions between argon metastable atoms and cadmium dihalide molecules have been studied in a flowing afterglow apparatus. The fluorescence spectra obtained in the range of 3000-7600 Å which result from the Ar(3P2) + CdX2 interactions indicate a dominant dissociative excitation production mechanism. The emission spectra are used to narrow the uncertainty in the currently accepted values for the dissociation energy of the CdX2 molecules. The Wigner spin rule (conservation of total electronic spin) was verified for these processes as shown by the dominance of final state triplet production as compared to the virtual absence of singlet spin state production. © 1988 American Institute of Physics

Spin-polarized 3He nuclear targets and metastable 4He atoms by optical pumping with a tunable, Nd:YAP laser

Several Nd:YAP lasers were constructed which could be broadly tuned in the 1083-nm region which includes the helium 23S-23P transition, using a Lyot filter and thin, uncoated etalons within the laser cavity. 1 W of power could be extracted at 1083 nm through a 1% transmitting output coupler. This laser beam was used to optically pump metastable 4He and 3He 23S helium atoms in a weak discharge cell, spin polarizing the metastable ensemble. In a 3He cell the polarization is transferred to the nuclear spin system. A 3He target cell at 0.3 Torr was polarized to 52% in a few minutes. We describe the application of this system to the design of polarized targets for experiments in nuclear physics

A High Power Lna Laser For Application To A New Polarized Electron Source

The recent development of high energy electron accelerators has generated a renewed interest in high current, high polarization electron sources. We have investigated several modifications to a method based on a pumped helium afterglow from which we expect improvements over the performances. These ones include the development of a high power, tunable LNA laser and the application of a new optical pumping scheme to the metastable helium atoms

Production of a high‐density state‐selected metastable neon beam

We have developed a high-density source of metastable neon and have selectively quenched both metastable species using a standing-wave dye laser. The source is compact, stable, and produces an average intensity of 3.6 x 1014 sr -1 s -1 and a density on target of 7.7 x 106 cm-3

Population policies and education: exploring the contradictions of neo-liberal globalisation

The world is increasingly characterised by profound income, health and social inequalities (Appadurai, 2000). In recent decades development initiatives aimed at reducing these inequalities have been situated in a context of increasing globalisation with a dominant neo-liberal economic orthodoxy. This paper argues that neo-liberal globalisation contains inherent contradictions regarding choice and uniformity. This is illustrated in this paper through an exploration of the impact of neo-liberal globalisation on population policies and programmes. The dominant neo-liberal economic ideology that has influenced development over the last few decades has often led to alternative global visions being overlooked. Many current population and development debates are characterised by polarised arguments with strongly opposing aims and views. This raises the challenge of finding alternatives situated in more middle ground that both identify and promote the socially positive elements of neo-liberalism and state intervention, but also to limit their worst excesses within the population field and more broadly. This paper concludes with a discussion outling the positive nature of middle ground and other possible alternatives

Laser Initiated Afterglow In A High Pressure K-Kr Mixture

We ionized potassium atoms in a K-Kr ([K] = 6 x 1014 cm-3: [Kr] = 2 x 1019 cm-3) mixture with a 120 μJ, 404 nm dye laser pulse in a stepwise absorption process and monitored the fluorescence spectra as a function of time. We saw a fast (≲20 ns) initial component due to electron excitation and a slow decay tail (≈10 μs) due to electron ion recombination. © 1978