Chris Jeynes

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PhD: "Carbonado and the diamond polishing process", Department of Physics,  University of Bristol, 1981 with Andrew Lang (now Prof.A.R.Lang FRS).  See:  C.Jeynes,  A proposed diamond polishing process, Phil.Mag. A42 (1983) 169-197 and C.Jeynes,  Natural polycrystalline diamond,  Ind.Diamond Rev.39  (1978) 14-23

1981:  Joined University of Surrey to work on epitaxial silicon deposition with Ian Wilson.  See:  M.Milosavljevic, C.Jeyens (sic), I.H.Wilson,  Low-temperature epitaxial growth of (100) silicon,  Elec.Letts. 19 (1983) 669-671, M Milosavljevic,  C Jeynes,  I H Wilson, Solid phase epitaxy of evaporated amorphous silicon films, Appl. Phys. Lett. 45 (8) 874-876 (1984), M Milosavljevic,  C Jeynes,  I H Wilson, Epitaxial (100) silicon films grown at low temperatures in an electron-beam evaporator, J. Appl. Phys.  57 1252-1255 (1985)48 (2): 169-197 1983

1982:  Joined the University of Surrey Ion Beam Centre as Liaison Fellow

1989:  Promoted to Senior Liaison Fellow


Accurate Ion Beam Analysis

I have long believed that we do not generally get as much information from IBA spectra as we could.  Our first contribution to more detailed RBS analysis was a code to fit joined half-Gaussians (JHG) to data  (C Jeynes,  A C Kimber, High accuracy data from Rutherford backscattering spectra: Measurements of the range and straggling of 60-400 keV As implants into Si, J. Phys. D. 18 L93-L97 (1985);  A C Kimber,  C Jeynes, An application of the truncated two-piece normal distribution to the measurement of depths of arsenic implants in silicon. J. Roy. Stat. Soc. C36(3) 352-357 (1987)).

There were a number of useful application of this JHG code:  U Bangert,  P J Goodhew,  C Jeynes,  I H Wilson, Low energy (2-5 keV) argon damage in silicon, J. Physics. D. 19 (1986) 589-603;  R P Webb,  C Jeynes,  I H Wilson, The effect of angle of incidence on interface broadening, Nuclear Instr. & Methods B13 (1986) 449-452; Z.H.Jafri, C.Jeynes, R.P.Webb, I.H.Wilson, Observation of swelling and sputtering of a Si target under Ar ion irradiation using a double marker technique, Vacuum 39 (1989) 1119-21;  Z.H.Jafri, C.Jeynes, R.P.Webb, I.H.Wilson, Mass transport of Silicon during Argon irradiation employing a double marker system, Nucl. Instruments & Methods B48  (1990) 457-460.

I have also used this JHG code participating in a Round Robin to use RBS to measure the thickness of Ta2O5 layers on Ta organised by Martin Seah of the National Physical Laboratory:  M P Seah,  D David,  J A Davies,  C Jeynes,  C Ortega,  C Sofield,  G Weber, An intercomparison of absolute measurements of the oxygen and tantalum thickness of Ta2O5 reference materials BCR 261 by Six laboratories, Nucl.Instruments & Methods B30 (1988) 140-51.

We were the first to critically demonstrate 1% absolute accuracy in determining the stoichiometry of InGaAs films by RBS:  C.Jeynes, Z.H.Jafri, R.P.Webb, M.J.Ashwin,  A.C.Kimber, Accurate RBS measurements of the In content of InGaAs thin films,  Surf.Interface Anal. 25 (1997) 254-260.  In this work we also proposed and demonstrated a simple pulse pileup calculation that can be incorporated in spectrum simulation.

We have critically demonstrated that, with care, the electronic gain of the spectroscopy system for standard He RBS can be determined to 0.5%:  C.Jeynes,  N.P.Barradas,  M.J.Blewett,  R.P.Webb, Improved ion beam analysis facilities at the University of Surrey,  Nucl. Instr. and Methods B136-138 (1998) 1229-1234.  It is surprising that in fact it is pretty difficult to get better than this,  and no-one has demonstrated better accuracy.  For example,  Lennard (et al, NIM B45, 1990, 281) in his work on the pulse height deficit of detectors implicitly gets the same accuracy.

The IBA DataFurnace

Really,  this is a continuation of the "Accurate IBA" theme.  Nuno Barradas and I (with support from Roger Webb) invented the DataFurnace in 1997 as an automated way of getting depth profiles out of "hard" RBS spectra.  We were the first to use the simulated annealing algorithm to do this,  and no-one to date can invert IBA spectra as easily, robustly and accurately as we can.  

We first published this work as: N.P.Barradas,  C.Jeynes,  R.P.Webb, Simulated annealing analysis of Rutherford backscattering data, Appl.Phys.Lett. 71 (1997) 291-3.
There is now a large literature on DataFurnace and a full-length Topical Review has been published (C.Jeynes et al  J.Phys.D 36, 2003, R97-R126).  See the DataFurnace web pages.

Other interests >>>

Page updated by C.Jeynes 9th February 2011

University of Surrey Ion Beam Centre,  Nodus Centre,  Stag Hill,  Guildford GU2 7XH
tel: (+44) 1483 689829