highly charged ion astrophysics in the laboratory: a new ...hci beam x-rays electrons sputtered...

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: sosolik@clemson.edu

864-656-0310