Dispensing with magnets?
Just as with single crystals, SWNTs open up the possibility of bending, focusing and accelerating high-energy particle beams without the use of large electromagnets. The relatively small dechannelling effects in SWNTs could even lead to revolutionary designs for high-luminosity colliders at energies greater than 0.1-1 TeV.
Unfortunately, current nanotechnology cannot produce nanotubes oriented with angular deviations less than the critical Lindhard angles that are necessary to provide the particle channelling. No methods for producing regularly deformed nanotubes have been developed, so these dreams cannot yet be realized.
However, other nanotube applications do appear to be realistic. Experiments carried out from 1995 until 2000 with static electric fields show that nanotubes have intriguing electron field emission properties. MWNTs with hemispherical fullerene tips provide more intense and stable beams. No experimental data exist for pulsed electric fields.
On the other hand, experiments on self-amplified spontaneous emission on advanced methods of particle acceleration and the production of higher-brightness photon beams require low emittance intense electron femtosecond beams.
At present, such beams are produced using field-, thermo- or photo-emission from various cathodes in radiofrequency guns, the very high accelerating fields of which protect the pulses from being blurred by strong space-charge repulsion.
Experiments using other materials suggest that higher breakdown voltages and current brightness can be achieved using shorter pulses, so it is reasonable to begin the study of the field- and photo-emission from nanotubes in pulsed regimes and in radiofrequency guns, although the corresponding theory of the field emission from the tips of nanotubes with a very small curvature radius has not yet been developed.
Further reading
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X Artru and T Qasmi (in press) Nucl. Instr. and Meth.
R O Avakian et al. 1999 Proc. RREPS-99 (Baikal, Russia).
R O Avakian et al. 2000 (in press) Nucl. Instr. and Meth.
J M Bonard et al. 2000 Appl. Phys. A, Mater. Sci. & Proc. 69 245.
W A de Heer, A Chatelain and D Ugarte 1995 Science 270 1179.
L A Gevorgian et al. 1997 Pisma Zh. Eksp. Teor. Fiz. 66 304.
L A Gevorgian, K A Ispirian and R K Ispirian 1997 Proc. RREPS-1997 (Tomsk, Russia).
L A Gevorgian, K A Ispirian and R K Ispirian 1998 Nucl. Instr. and Meth. B145 155.
V V Klimov and V S Lethokhov 1996 Phys. Lett. A222 424.
V V Klimov and V S Lethokhov 1997 Phys. Lett. A424 226, 244.
R Saito, G Dresselhaus and M S Dresselhaus 1998 Physical Properties of Carbon Nanotubes (Imperial College Press, London).
A Thess et al. 1996 Science 273 483.
N K Zhevago and V I Glebov 1998 Phys. Lett. A250 390.
N K Zhevago and V I Glebov 2000 (in press)Zh. Eksp. Teor. Fiz.