1 | By R.P.Kokoulin, May 12th, 2000 |
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2 | |
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3 | Multiple Coulomb Scattering some questions and problems |
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4 | |
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5 | Apart from the problems of creation and development of convenient |
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6 | procedure for fast simulation of the effect, some principal questions are to be |
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7 | answered (possibly, most of them have already been investigated) |
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8 | |
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9 | General |
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10 | |
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11 | Is it possible to use cross section formulae without magnetic formfactor and spin effects: |
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12 | |
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13 | a) for nucleus (probably yes); |
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14 | b) for proton (possibly yes); |
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15 | c) for electron (probably no). |
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16 | |
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17 | Should the scattering on the screened nucleus and on atomic electrons be considered |
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18 | separately? (likely, they should; they probably can be combined later, but
) |
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19 | |
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20 | Scattering on the nucleus: |
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21 | |
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22 | a) influence of the choice of the elastic atomic formfactor (TF, HF, hydrogen-like,
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23 | there is a hope that the difference is small (with a proper choice of the parameters) but |
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24 | it should be estimated; |
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25 | b) influence of the nuclear size (it should influence RMS angle and distribution shape on |
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26 | the tail); |
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27 | c) influence of the choice of nuclear formfactor (exponential, Gaussian, Fermi model, |
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28 | etc.); probably, it is small (only RMS nucleus radius is crucial) but it is better to |
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29 | compare directly; |
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30 | d) contribution of inelastic nucleus formfactor (incoherent scattering on protons of the |
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31 | nucleus); |
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32 | e) necessity of taking into account proton formfactor (for incoherent scattering); last two |
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33 | points are expected to give small effect but need evaluation. |
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34 | |
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35 | Scattering on atomic electrons: |
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36 | |
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37 | a) introduction and influence of the choice of inelastic atomic formfactor (TH, |
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38 | hydrogen-like exponential, what else?) it should be evaluated; more simple |
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39 | approaches, such as Z(Z+1) substitutions, seem to be incorrect; |
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40 | b) problem of a double account for scattering on electrons if explicit simulation of the |
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41 | elastic scattering of the projectile on electrons (possibly, above the cut Tcut) is |
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42 | included (knock-on electron production with full kinematics) the possible way is to |
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43 | consider restricted multiple scattering (below Tcut). |
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44 | |
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45 | |
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