FAST-ION-BEAM ATOMIC SPECTROSCOPY

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FAST-ION-BEAM ATOMIC SPECTROSCOPY

• Toledo Heavy Ion Accelerator
• (THIA)
• Laboratory

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700 Li beam (v4.4 mm/ns) incident on a thin (3
?g/cm2) carbon foil. The blue light is H-like
4f-5g in Li2 (?4500Å, ?3 ns, ?x1.3 cm). The
green light is He-like 2s 3S-2p 3P in Li
(?5485Å, ?44 ns, ?x19 cm).
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McMaster Hall Room 1019
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Multiplexed Simultaneous PSD Efficient
detection of a range of ?s Allowed
forbidden transitions are manifest Time-dep
beam fluctuations cancel in ratios
line profiles reveal blends
bkgds obtained between lines
ANDC possible in real time
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Fast ion beams incident on a thin foil can
produce highly ionized atoms like those found in
the solar corona
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1951 King Gustav IV Adolf
Professor Bengt Edlén
Discoverer of highly ionized atoms in the solar
corona.
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The emitted radiation from an impulsively
excited level diminishes exponentially with
time. If the level is repopulated from higher
lying levels, and/or is blended with light from
other transitions with similar wavelengths, the
decay is a sum of exponentials. These
non-orthogonal functions can be untangled by the
ANDC technique devised in the UT laboratory.
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Adjusted Normalization of Decay Curves
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ANDC Method
Eliminate Cascading
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Because the beam foil excitation time is short
compared to the uncertainty,
and excitation is anisotropic because
of the preferred direction of the Beam, the
wave function is revealed as Quantum
Beats.
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Differential Quantum Beat Measurements
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The lifetime of a decay is a measure of rate of
depopulation of the upper level. This
depopulation may occur by multiple decay channels
to lower levels. To determine intensities of
individual channels, both the Lifetime and the
Branching Fractions must be known.
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Ca II
Branching fractions VIS, IR, UV,
VUV calibrations needed
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Determination of branching fractions
Requires intensity calibration of detection
apparatus as a function of wavelength
Standard lamps continuum radiation
fixed in laboratory
beam light Doppler shifted
Line standards available in Visible, but not UV
Need in-beam ions with known intensity ratios
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X-ray laser
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Mission-Driven Development
and Curiosity-Driven Research
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Thanks to John Delos, College of William Mary
In 1903, the transportation industry in the US
was dominated by the railroads. (Below the
Empire State Express, which set the world speed
record of 112.5 mph in 1893)
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They had laid a 1/4 million miles of track (the
distance from the earth to the moon) and were
still expanding, laying down 6000 miles/year
(equivalent to twice across the continent.
(Below a map of the railroads in America in 1890)
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They had over 1.5 million employees, their
investment was over 12 billion in 1903 dollars,
they carried 30 billion passenger-miles, and
their major stations were like monuments or
temples, built to last (like their industry)
forever.
Their leaders were among the most intelligent,
powerful, aggressive and wealthiest men in the
world, and they had the power to do whatever they
wanted in transportation.
That year, 1903, the first working airplane was
built by two guys from Dayton who worked in
a bicycle shop.
- John Delos