FAST-ION-BEAM ATOMIC SPECTROSCOPY Toledo Heavy Ion Accelerator (THIA) Laboratory

FAST-ION-BEAM ATOMIC SPECTROSCOPY

Toledo Heavy Ion Accelerator

(THIA)

Laboratory

700 Li+ beam (v=4.4 mm/ns) incident on a thin (3 g/cm2) carbon foil. The blue light is H-like 4f-5g in Li2+ (4500Å, =3 ns, x=1.3 cm).

The green light is He-like 2s 3S-2p 3P in Li+ (5485Å, =44 ns, x=19 cm).

McMaster Hall Room 1019

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

Fast ion beams incident on a thin foil can produce highly ionized atoms like those found in

the solar corona

1951

King Gustav IV Adolf

Professor Bengt Edlén

Discoverer ofhighly ionized atoms in the solar corona.

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.

Adjusted Normalization of Decay Curves

ANDCMethod

EliminateCascading

Because the beam foil excitation time is short compared to the uncertainty, andexcitation is anisotropic because ofthe preferred direction of the Beam,

the wave function is revealed as “Quantum Beats”.

Differential Quantum Beat Measurements

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.

Ca II

Branching fractions:VIS, IR, UV, VUVcalibrations needed

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

X-ray laser

Mission-Driven Development

and

Curiosity-Driven Research

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)

Thanks to John Delos, College of William & Mary

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)

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