3 research outputs found
Optogalvanic Spectroscopy of Metastable States in Yb^{+}
The metastable ^{2}F_{7/2} and ^{2}D_{3/2} states of Yb^{+} are of interest
for applications in metrology and quantum information and also act as dark
states in laser cooling. These metastable states are commonly repumped to the
ground state via the 638.6 nm ^{2}F_{7/2} -- ^{1}D[5/2]_{5/2} and 935.2 nm
^{2}D_{3/2} -- ^{3}D[3/2]_{1/2} transitions. We have performed optogalvanic
spectroscopy of these transitions in Yb^{+} ions generated in a discharge. We
measure the pressure broadening coefficient for the 638.6 nm transition to be
70 \pm 10 MHz mbar^{-1}. We place an upper bound of 375 MHz/nucleon on the
638.6 nm isotope splitting and show that our observations are consistent with
theory for the hyperfine splitting. Our measurements of the 935.2 nm transition
extend those made by Sugiyama et al, showing well-resolved isotope and
hyperfine splitting. We obtain high signal to noise, sufficient for laser
stabilisation applications.Comment: 8 pages, 5 figure
HEPA respirators and tuberculosis in hospital workers
Adal et al. (July 21 issue)1 demonstrate that at the University of Virginia Hospital, where the incidence of tuberculosis is low, the infection controls already instituted may be sufficient and the cost of adding respirators with high-efficiency particulate air filters (HEPA respirators) for their 3852 workers is impressively high. The situation is different at our hospital, Lincoln Medical and Mental Health Center in South Bronx, New York. In contrast to their figure of 11 patients with documented tuberculosis per year, we have over 160 such patients per year, of whom approximately 30 percent have multidrug-resistant tuberculosis