Buffer gas cooling and trapping of atoms with small magnetic moments

Buffer gas cooling was extended to trap atoms with small magnetic moment (mu). For mu greater than or equal to 3mu_B, 1e12 atoms were buffer gas cooled, trapped, and thermally isolated in ultra high vacuum with roughly unit efficiency. For mu < 3mu_B, the fraction of atoms remaining after full thermal isolation was limited by two processes: wind from the rapid removal of the buffer gas and desorbing helium films. In our current apparatus we trap atoms with mu greater than or equal to 1.1mu_B, and thermally isolate atoms with mu greater than or equal to 2mu_B. Extrapolation of our results combined with simulations of the loss processes indicate that it is possible to trap and evaporatively cool mu = 1mu_B atoms using buffer gas cooling.Comment: 17 pages, 4 figure

A trimodal resonator for three mutually perpendicular magnetic fields

We describe a trimodal resonator for the simultaneous delivery of three perpendicular magnetic fields. The resonator consists of a shielded loop single-mode radio frequency (rf) resonator placed inside of a bimodal waveguide microwave resonator. The microwave modes are nondegenerate, tunable over a range of 100 MHz, and have typical Q factors of 150 and 200. The rf mode is tunable over a range of 125 MHz, and has a typical Q of 45. Control of the relative phase between the three fields is demonstrated. The resonator will be used to drive three magnetic dipole transitions coherently between Zeeman states in the ground state of 87Rb.87Rb. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71204/2/RSINAK-70-3-1780-1.pd

Deep superconducting magnetic traps for neutral atoms and molecules

The design, construction and testing of deep superconducting magnetic traps for neutral atoms and molecules were studied. The support structure was designed to be simple in order to avoid unforeseen stress concentrations which led to catastrophic mechanical failure. Optical access to the trapping region along the axial direction was provided by the 76.5 mm bore of the magnet. The results show that the magnet temperatures much below 4.2 K necessitate the use of a different material for the support structure in the applications which required the magnet to be run at low currents

Using USP I and USP IV for discriminating dissolution rates of nano- and microparticle-loaded pharmaceutical strip-films.

Recent interest in the development of drug particle-laden strip-films suggests the need for establishing standard regulatory tests for their dissolution. In this work, we consider the dissolution testing of griseofulvin (GF) particles, a poorly water-soluble compound, incorporated into a strip-film dosage form. The basket apparatus (USP I) and the flow-through cell dissolution apparatus (USP IV) were employed using 0.54% sodium dodecyl sulfate as the dissolution medium as per USP standard. Different rotational speeds and dissolution volumes were tested for the basket method while different cell patterns/strip-film position and dissolution media flow rate were tested using the flow-through cell dissolution method. The USP I was not able to discriminate dissolution of GF particles with respect to particle size. On the other hand, in the USP IV, GF nanoparticles incorporated in strip-films exhibited enhancement in dissolution rates and dissolution extent compared with GF microparticles incorporated in strip-films. Within the range of patterns and flow rates used, the optimal discrimination behavior was obtained when the strip-film was layered between glass beads and a flow rate of 16 ml/min was used. These results demonstrate the superior discriminatory power of the USP IV and suggest that it could be employed as a testing device in the development of strip-films containing drug nanoparticles

Buffer gas cooling and trapping of atoms with small effective magnetic moments

We have extended buffer gas cooling to trap atoms with small effective magnetic moments µeff . For µeff ≥ 3µB, 1012 atoms were buffer gas cooled, trapped, and thermally isolatedin ultra high vacuum with roughly unit efficiency. For µeff < 3µB, the fraction of atoms remaining after full thermal isolation was limitedby two processes: windfrom the rapid removal of the buffer gas anddesorbing helium films. In our current apparatus we trap atoms with µeff ≥ 1µB, andthermally isolate atoms with µeff ≥ 1.8µB. This triples the number of atomic species which can be buffer gas cooledandtrappedin thermal isolation. Extrapolation of our results andsimulations of the loss processes indicate that it is possible to trap and evaporatively cool 1µB atoms using buffer gas cooling.Physic