highly charged ion astrophysics in the laboratory: a new ...hci beam x-rays electrons sputtered...
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Highly Charged Ion Astrophysics
in the Laboratory:
A New User Facility at
Clemson University
Chad E. Sosolik
Dept. of Physics and Astronomy
Clemson’s New User Facility
Highly charged ion (HCI) production
◦ Electron Beam Ion Trap (EBIT)
Ion extraction and transport
◦ Custom beamline
HCI-materials interactions
◦ UHV vacuum chambers (target, prep, etc.)
◦ Measurement/Detection tools
ions, electrons, mass loss, x-rays
Proposal – MRI-R2
Five Emphasis Areas
◦ Surface and Interface Nanoscience
◦ Electronic Materials and Devices
◦ Fusion-Relevant Materials Studies
◦ Laboratory Astrophysics
◦ Radiation Effects on Electronics
Proposal – MRI-R2
Building a User/Collaborator Base Five Emphasis Areas
◦ Surface and Interface Nanoscience
◦ Electronic Materials and Devices
◦ Fusion-Relevant Materials Studies
◦ Laboratory Astrophysics
◦ Radiation Effects on Electronics
Clemson University
Electron Beam Ion Trap (CUEBIT)
Funded (March 15, 2010)
◦ National Science Foundation
Equipment/Facilities Funds ($1.65 million)
◦ Clemson University
Staff Operator/Technician (search soon!)
Fully renovated laboratory space (in progress)
Three years of committed shop time
The EBIT in CUEBIT
Mort Levine and Ross Marrs with the first EBIT at LLNL.
Born 29 October 1986
LLNL
The EBIT in CUEBIT
A Penning trap with an intense, monoenergetic,
electron beam down the axis.
The EBIT in CUEBIT
Energy
(q*V)
X (position)
E1
(200 V)
E2
(100 V)
E3
(200 V)
B field
Trapped Ions
(or electrons)
Highly Charged Ions
Definition(s)
◦ An atom missing more than 1or 2 electrons
◦ An atom missing several dozen electrons
◦ Any atom that has been stripped of a large
number of electrons (Q » 1) such that the
total energy yielded during reneutralization
(E0) is outside the realm of ordinary
experience with laboratory ions (E0 » 10 eV)Ref: J.D. Gillaspy, J. Phys. B. 34, R93 (2001).
Highly Charged Ions
Neutralization Energy
◦ the sum of all the ionization energies of the
charge states at and below the ion
Highly Charged Ions
Neutralization Energy
Xenon(isonuclearsequence)
Hydrogen(scaled)
Highly Charged Ions
Neutralization Energy
HCI-Materials Interactions
The Basic Picture
q+
q-
e-e-
e-
x-rayx-ray
Resonant
neutralization
e- and x-ray
emission
Desorption and
sputtering
e-
“hollow atom”
q+
q-
e-e-
e-
x-rayx-ray
Resonant
neutralization
e- and x-ray
emission
Desorption and
sputtering
e-
“hollow atom”
CUEBIT: The Plan
CUEBIT: The Plan
HCI Beam
CUEBIT: The Plan
HCI Beam
X-rays
Electrons
Sputtered Particles
Scattered Ion/Atoms
Real-time mass loss
Sample control (heated/cooled)
HCIs: Laboratory Astrophysics
Cosmic chronometers (Cosmochronometry)
◦ time span of nucleosynthesis in our galaxy
◦ Example: decay products of Re-187 in meteorites
Neutral Re – half life of 4.2 x 109 yrs
Highly ionized Re – half life of 33 yrs
Ref: F. Bosch et al., Phys. Rev. Lett. 77, 5190(1996).
◦ Decay proceeds more rapidly through electron capture
than escape
HCIs: Laboratory Astrophysics
X-ray astrophysics
◦ radiation encountered is signature of complex events
exploding stars, matter falling into black holes
highly ionized matter
◦ Two facts:
Earth’s atmosphere is opaque to x-rays
HCIs don’t occur naturally on Earth
◦ How do you test detectors and the theoretical models
used to interpret your data?
............with an EBIT............
HCIs: Laboratory Astrophysics
Charge Exchange Measurements
◦ Neutral gas injected into the EBIT
◦ Detection of emitted X-rays
Comet in a lab
Charge exchange between O8+, Ne10+ and various targets (e.g.
H20, CH4, and CO2)
Ref: S. Otranto, R.E. Olson, andP. Beiersdorfer, Phys. Rev. A 73, 022723(2006)
Absolute excitation cross sections
Calibration of intensity ratios
the 3d-2p to 3s-2p transitions in neon-like Fe16+
HCIs: Laboratory Astrophysics
Materials synthesis in space
◦ Nanodiamond dust postulated in the interstellar medium
Related to spectral signature of quasars
Ref: L. Binette et al., Ap. J. 631, 661(2005).
Found in meteorites
◦ HCI irradiation of graphite (in the laboratory)
Nanoscale diamond-like structure formation
Ref: E. Sideras-Haddad et al., Nucl. Instrum. Meth. B 267, 2774 (2005).
CUEBIT: What should we plan for?
HCI Beam
X-rays
Electrons
Sputtered Particles
Scattered Ion/Atoms
Real-time mass loss
Sample control (heated/cooled)
From the NSF-MRI-R2 proposal:
“We will: i) operate as a user facility for ground-based exposures of astrophysically
relevant surfaces, and ii) conduct fundamental research into astrophysical ices and dust
on supported substrates as they relate to the evolution of interstellar matter. ”
CUEBIT: What should we plan for?
HCI Beam
X-rays
Electrons
Sputtered Particles
Scattered Ion/Atoms
Real-time mass loss
Sample control (heated/cooled)
Thanks to
◦ The Organizers
◦ National Science Foundation
Highly Charged Ion Astrophysics
in the Laboratory:
A New User Facility at
Clemson University
Chad E. Sosolik
Dept. of Physics and Astronomy
Email: [email protected]
864-656-0310