BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:1
UID:UW-Physics-Event-4830
DTSTART:20180420T183000Z
DURATION:PT1H0M0S
DTSTAMP:20260414T225342Z
LAST-MODIFIED:20180418T171159Z
LOCATION:2241 Chamberlin Hall
SUMMARY:UW Laboratory Astrophysics\, JIMFEST 2018\, Elizabeth DenHarto
 g\, University of Wisconsin-Madison
DESCRIPTION:In this talk I will describe the laboratory astrophysics p
 rogram of the Jim Lawler group at the University of Wisconsin – Madi
 son\, focusing on the laboratory techniques and instruments used for t
 he measurement of transition probabilities.  Transition probabilities 
 are determined from the combination of radiative lifetimes and branchi
 ng fractions.  Radiative lifetimes are measured using time-resolved la
 ser-induced fluorescence on a slow atomic/ionic beam.  This experiment
  has been extremely productive over the 3+ decades of its operation.  
 The atomic beam source at the heart of this experiment was designed by
  Jim in the early 1980’s\, and can produce a gas phase neutral and s
 ingly-ionized sample of any metal\, and many non-metals.  This source 
 is a big reason for the success and productivity of this experiment.  
 Branching fractions are measured in emission using Fourier transform o
 r grating spectroscopy\, or a combination thereof.  Fourier Transform 
 spectrometers have many advantages for branching fraction work\, but h
 ave one major drawback.  As with any interferometric device\, the nois
 e from all lines in the spectrum distribute evenly throughout the spec
 trum\, making the measurement of very weak branches difficult to impos
 sible.  I will describe a more recent instrument of Jim’s design –
  the 3 meter echelle spectrograph – which is ideal for the measureme
 nt of the branching fractions of very weak spectral lines.
URL:https://www.physics.wisc.edu/events/?id=4830
END:VEVENT
END:VCALENDAR