Gabriele Cosmo
46 lines
2.0 KiB
Plaintext
46 lines
2.0 KiB
Plaintext
By R.P.Kokoulin, May 12th, 2000
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Multiple Coulomb Scattering – some questions and problems
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Apart from the problems of creation and development of convenient
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procedure for fast simulation of the effect, some principal questions are to be
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answered (possibly, most of them have already been investigated)
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General
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Is it possible to use cross section formulae without magnetic formfactor and spin effects:
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a) for nucleus (probably yes);
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b) for proton (possibly yes);
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c) for electron (probably no).
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Should the scattering on the screened nucleus and on atomic electrons be considered
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separately? (likely, they should; they probably can be combined later, but…)
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Scattering on the nucleus:
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a) influence of the choice of the elastic atomic formfactor (TF, HF, hydrogen-like, …);
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there is a hope that the difference is small (with a proper choice of the parameters) but
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it should be estimated;
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b) influence of the nuclear size (it should influence RMS angle and distribution shape on
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the tail);
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c) influence of the choice of nuclear formfactor (exponential, Gaussian, Fermi model,
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etc.); probably, it is small (only RMS nucleus radius is crucial) but it is better to
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compare directly;
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d) contribution of inelastic nucleus formfactor (incoherent scattering on protons of the
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nucleus);
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e) necessity of taking into account proton formfactor (for incoherent scattering); last two
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points are expected to give small effect but need evaluation.
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Scattering on atomic electrons:
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a) introduction and influence of the choice of inelastic atomic formfactor (TH,
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hydrogen-like exponential, what else?) – it should be evaluated; more simple
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approaches, such as Z(Z+1) substitutions, seem to be incorrect;
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b) problem of a double account for scattering on electrons if explicit simulation of the
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elastic scattering of the projectile on electrons (possibly, above the cut Tcut) is
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included (knock-on electron production with full kinematics) – the possible way is to
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consider restricted multiple scattering (below Tcut).
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