<< Chapter < Page Chapter >> Page >

In electron microscope the electron can be accelerated to higher energy to obtain a finer resolution. It can resolve on the scale of molecules but can barely perceive the atoms.

To resolve at atomic and sub-atomic level we need to go to particle accelerators. Particle Accelerators are gargantuan machines which can be regarded as giant microscopes for probing into the innermost recesses of matter - an awesome complement to the giant telescopes which probe to the edges of the Universe .

To arrive at the resolving power of particle accelerator we must know Special Theory of Relativity and we must make relativistic corrections in order to arrive at the correct resolving power of the particle accelerators. These are described in the Appendix XXXXIV . Here we will just use them to arrive at the resolving power of the particle accelerators.

Relativistic momentum is related to the total energy E by the following relation ship:


de Broglie wavelength associated with this particle is:


Using Equation (1.99), the resolving power of various particle accelerators operational around the world is tabulated in Table(1.13).[Taken from Table(9.1), “Overview of Particle Physics”, by Abdus Salam, New Physics, edited by Paul Davies, Cambridge University Press, 1992]

Table 1.13. The resolution of the particle accelerators around the World.

Name&Location Energy reached Year Resolution Particle detected
Rutherford*Manchester,UK. Alpha decay10MeV,alpha particle’s velocity= 2×10 7 m/s, Alpha particle=4He nucleus; 1911 4.5×10^ -15 m Nucleus size= 10^ -14 m; Rutherford determined the size to be 30fmBut the correct estimate is 7fm;
1919 1.24×10^ -15 m Protonssize= 10^ -15 m=1fm;
1932 1.24×10^ -15 m Neutronssize= 10^ -15 m =1fm
1GeV 1.24×10^ -15 m
Bepc(e + e - ) Beijing 4GeV 1987
TRISTAN(e + e - ) Japan 60GeV 1987
10GeV 1979 1.24×10^ -16 m Quarks size= 10^ -16 m
SLC(e + e - ) Stanford,California,USA; 100GeV 1987 1.24×10^ -17 m W - , W + &Z 0 detected
LEP(I) (e + e - ) Large electron-positron collidorCERN, Geneva; 100GeV 1987 1.24×10^ -17 m
LEP(II) (e + e - ) CERN,Geneva 200GeV 1995 6.2×10^ -18 m Top Quarksdetected
HERA(ep)Hamburg 320GeV 1991 3.87×10^ -18 m
SpSCERN, Geneva 900GeV 1986 1.38×10^ -18 m
TevatronFermiLab,USA 1TeV 1987 1.24×10^ -18 m No excited state of quarks or leptons detected size= 10^ -18 m
TevatronFermiLab,USA 2TeV 1987 6.2×10^ -19 m
UNKSerpukhov,Russia 3TeV 1995 4.13×10^ -19 m
EeSerpukhov,Russia 4TeV ? 3×10^ -19 m
Large HadronCollider(LHC),CERN,Geneva 16TeV ? 7.75×10^ -20 m
SSC(super particle superconductingCollider),USA; 40TeV ? 3.1×10^ -20 m
1PeV ? 1.24×10^ -21 m
1EeV ? 1.24×10^ -24 m

* the first particle accelerator was established at Cavendish Laboratory, Cambridge University. In 1919 Rutherford became the first Director and he was instrumental in establishing the particle accelerator.

In Metal the wavelength is comparable to the lattice constant. This is like light falling through a narrow aperture whose dimension is comparable to the wavelength. Incident light will form a circular diffraction pattern behind the aperture on the target screen. This implies that conducting electron in a metallic lattice is strongly scattered by the lattice centers. Hence it has a very low mobility.

In Semiconductor, the de Broglie wave length is much larger than the lattice constant. Hence lattice scattering is weak and only the gross imperfections cause the scattering. These gross imperfections could be phonons and dislocations extending over several lattice constants. This is what makes conducting electrons much more mobile in semiconductor as compared to that in metal.

In metal, conducting electrons behave like degenerate gas and not quite like ideal gas whereas in semiconductors they behave like non-degenerate gas which is more like ideal gas obeying ideal gas law.

In ideal gas the molecules are far apart, independent of one another and possessing average energy of (3/2)kT whereas in degenerate gas the molecules are closely packed and average kinetic energy is much larger than (3/2)kT. In Table(1.14),

Metals and Semiconductors parameters have been tabulated in the same table.

Table(1.14). Conductivity(σ), Fermi Level(E F ), Mean Free Path(L*) and Mean Free Time(τ) at 0°C for monovalent metals and semiconductors.

Metal σ (10 6 S/cm) ρ(Ω-cm) n (10^ 22 / cm 3 ) μ e cm^ 2 / (V-s)= σ/(nq) E F (eV) L*(A°) τ(fs)= m e μ/q ×10^ -4
Li 0.12 8.3 ×10^ -6 4.62 16.2 4.7 110 9
Na 0.23 4.35 ×10^ -6 2.65 54.17 3.1 350 31
K 0.19 5.26 ×10^ -6 2.1 370 44
Cu 0.64 1.67 ×10^ -6 8.5 47 7.0 420 27
Ag 0.68 1.47 ×10^ -6 5.9 72 5.5 570 41
Ge 47 n i = 2.25 ×10^ 13 3900 2106 2217
Si 300k n i = 1.15 ×10^ 10 1350 729 767.6
GaAs 70.5M n i =2 ×10^6 8600 4645.5 4890

Questions & Answers

How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
Researchers demonstrated that the hippocampus functions in memory processing by creating lesions in the hippocampi of rats, which resulted in ________.
Mapo Reply
The formulation of new memories is sometimes called ________, and the process of bringing up old memories is called ________.
Mapo Reply
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Solid state physics and devices-the harbinger of third wave of civilization. OpenStax CNX. Sep 15, 2014 Download for free at http://legacy.cnx.org/content/col11170/1.89
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Solid state physics and devices-the harbinger of third wave of civilization' conversation and receive update notifications?