Development of a Carbon Nanotube Stripper Foil Karl

Development of a Carbon Nanotube Stripper Foil Karl von Reden and Enid Sichel Geology and Geophysics Department Presented at the Symposium of Northeastern Accelerator Personnel 2003, Strasbourg, FR

Outline • • • Introduction: reasons for doing this State of the art in nanotube R&D Problems Our progress (so far) What is next?

Reasons for doing this Compact Accelerator Mass Spectrometry systems with accelerating voltages < 500 k. V are under development. Stripper* thickness needed: 2 – 5 mg/cm 2 Gas stripping requires large effort in vacuum pumping to reduce background from scattering outside of the stripper canal Characteristics of nanotubes and their (purified) aggregates might be superior to “traditional” amorphous, graphite, even diamond-like films…

State of the art in nanotube R&D “armchair” “zigzag” “chiral” STM: Venema et al. , 1998 M. Daenen et al. , 2003

SWNT ropes (from R. Smalley’s group) ~10 nm Thess et al. , 1996 Rinzler et al. , 1998

Who How Typ. Yield SWNT MWNT PRO CON M. Daenen et al. , 2003

Properties of single-walled carbon nanotubes (SWNT) and other forms of carbon SWNT Diamond Graphite Average diameter (nm) Length/diameter ratio Density (g/cm 3) Band gap (e. V) metallic SWNT semiconducting SWNT Resistivity (Wcm) Max. Current Density (A/m 2) Thermal Conductivity (k. W/m/K) 1. 3 » 1000 1. 35 0. 0 ~0. 5 10 - 4 1013 ~2 10+16 ~10 - 3 N/A ~2 0. 08 -0. 25 Young’s Modulus (Tpa) Max. Tensile Strength (Gpa) 1 ~100 0. 05 3. 5 5. 5 1. 8 0. 0

Problems? Homogeneity (pin holes, clusters) Required condition: Beam spot large compared to nano structure Constant average foil thickness (no taper or other macroscopic changes across the foil)

Thickness variability of foils (from AFM images) AD foil DLC foil Liechtenstein et al. 1999

Graphite foils Jeschke et al. , 2001

Progress (so far) Collaborations or contacts started with Doug Chrisey, NRL “MAPLE” Facility Gary Wnek, VCU “Electro-spinning Facility” Frank Hennrich, Uni. Karlsruhe, FZK Commercial Suppliers Testing possible at Paul Skipper’s biomedical AMS Facility at MIT or at the NRL TEAMS Laboratory

MAPLE Pique, Mc. Gill, Chrisey, 2000

Electro-spinning D. Li et al. (UW), 2003

DC glow discharge, RF glow discharge Liechtenstein et al. , 1997

Laser plasma ablation deposition Maier-Komor, 1995

Laser ablation Lebedkin et al. , FZK (2001)

Hennrich et al. 2002

Hennrich et al. 2002 Hennrich - 2

Commercial SWNT films

What is next? Try out Karlsruhe type film in one of the AMS labs with accessible terminals Follow SWNT R&D (mats of highly aligned few-mm-long SWNT ropes desirable) Consider other structures: Stripper canals filled with “nano wool”? This work is supported by a grant from WHOI’s “Cecil H. & Ida M. Green Technology Innovation Awards”