210 research outputs found
Observation of Spin Flips with a Single Trapped Proton
Radio-frequency induced spin transitions of one individual proton are
observed for the first time. The spin quantum jumps are detected via the
continuous Stern-Gerlach effect, which is used in an experiment with a single
proton stored in a cryogenic Penning trap. This is an important milestone
towards a direct high-precision measurement of the magnetic moment of the
proton and a new test of the matter-antimatter symmetry in the baryon sector
Resolution of Single Spin-Flips of a Single Proton
The spin magnetic moment of a single proton in a cryogenic Penning trap was
coupled to the particle's axial motion with a superimposed magnetic bottle.
Jumps in the oscillation frequency indicate spin-flips and were identified
using a Bayesian analysis.Comment: accepted for publication by Phys. Rev. Lett., submitted 6.June.201
Demonstration of the Double Penning Trap Technique with a Single Proton
Spin flips of a single proton were driven in a Penning trap with a
homogeneous magnetic field. For the spin-state analysis the proton was
transported into a second Penning trap with a superimposed magnetic bottle, and
the continuous Stern-Gerlach effect was applied. This first demonstration of
the double Penning trap technique with a single proton suggests that the
antiproton magnetic moment measurement can potentially be improved by three
orders of magnitude or more
Albuterol metered dose inhaler performance under hyperbaric pressures
Comparative Medicine - OneHealth and Comparative Medicine Poster SessionINTRODUCTION: The stimulus for this presentation was an asthma attack suffered on the first dive by a victim of a severe industrial electrical burn. The patient's response to albuterol metered dose inhaler (MDI) treatment given at depth was felt to have been poor. We thus wondered what the output of these devises (chlorofluorocarbon or CFC) was at therapeutic depth versus normobaria. As the current MDIs were being phased out of use we also wondered what the comparable output characteristics of the replacement MDIs (hydrofluoroalkane or HFA) would be.
MATERIALS AND METHODS: The dose and aerosol particle size and number delivered by MDIs were measured in a hyperbaric chamber at pressures ranging from one atmosphere absolute (1 ATA, 0 feet of seawater, fsw, 101 kPa) to three ATA (66 fsw, 304 kPa). Mass delivered was measured by a Sartorius B120 analytical balance, and particle size analysis by a TSI 3080L electrostatic classifier with a TSI 3776 ultrafine condensation particle counter.
RESULTS: Dose delivery per actuation by CFC and long canister HFA powered MDIs was 13±1% and 12±1% less, respectively, at 3 ATA compared to 1 ATA. However, dose delivery by short canister HFA MDIs was not significantly changed with pressure. The geometric mean diameters of nano particles from the CFC and short canister HFA MDIs decreased from 50 nm at 0 fsw to 32 nm at 66 fsw whereas the long canister HFA aerosol diameters were not affected. The numbers of nanometer size particles delivered at 66 fsw were only 4-7% of those delivered at 0 fsw for the CFC and long canister HFA MDIs; whereas for the short canister HFAs it was 26%.
CONCLUSIONS: The doses of albuterol and the sizes and numbers of aerosol particles emitted from albuterol MDIs actuated in a hyperbaric environment vary by canister type; CFC MDI loss is probably unimportant
Direct high-precision measurement of the magnetic moment of the proton
The spin-magnetic moment of the proton is a fundamental property of
this particle. So far has only been measured indirectly, analysing the
spectrum of an atomic hydrogen maser in a magnetic field. Here, we report the
direct high-precision measurement of the magnetic moment of a single proton
using the double Penning-trap technique. We drive proton-spin quantum jumps by
a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic
field. The induced spin-transitions are detected in a second trap with a strong
superimposed magnetic inhomogeneity. This enables the measurement of the
spin-flip probability as a function of the drive frequency. In each measurement
the proton's cyclotron frequency is used to determine the magnetic field of the
trap. From the normalized resonance curve, we extract the particle's magnetic
moment in units of the nuclear magneton . This
measurement outperforms previous Penning trap measurements in terms of
precision by a factor of about 760. It improves the precision of the forty year
old indirect measurement, in which significant theoretical bound state
corrections were required to obtain , by a factor of 3. By application
of this method to the antiproton magnetic moment the fractional
precision of the recently reported value can be improved by a factor of at
least 1000. Combined with the present result, this will provide a stringent
test of matter/antimatter symmetry with baryons.Comment: published in Natur
The magnetic moments of the proton and the antiproton
Recent exciting progress in the preparation and manipulation of the motional
quantum states of a single trapped proton enabled the first direct detection of
the particle's spin state. Based on this success the proton magnetic moment
was measured with ppm precision in a Penning trap with a superimposed
magnetic field inhomogeneity. An improvement by an additional factor of 1000 in
precision is possible by application of the so-called double Penning trap
technique. In a recent paper we reported the first demonstration of this method
with a single trapped proton, which is a major step towards the first direct
high-precision measurement of . The techniques required for the proton
can be directly applied to measure the antiproton magnetic moment
. An improvement in precision of by more than
three orders of magnitude becomes possible, which will provide one of the most
sensitive tests of CPT invariance. To achieve this research goal we are
currently setting up the Baryon Antibaryon Symmetry Experiment (BASE) at the
antiproton decelerator (AD) of CERN
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