Below you will find short instructions how to use CRYSON by Dmitri Svergun. Instructions for CRYSOL are here.
The information below corresponds to the file /hosts/lass2/d1/lss/svergun/Crysol/cryson.ins.

At the ILL, use the command cryson.

C R Y S O N

This is a short information on how to use beta-release of Cryson,
which is a version of CRYSOL for neutron scattering.

IBM-PC version:

Hardware requirements: IBM-PC compatible (486 and higher)
with 2 Mb RAM and VGA or SVGA graphic card.

Operating systems:

DOS/Win3.1/Win95/WinNT.
The program works in a full-screen DOS window.
Under Win3.1 one should call a full-screen DOS prompt.
Under Win95, one should invoke a Real DOS mode.
Under WinNT, one should reboot in DOS mode or
                          switch off the EMS usage in the properties of the DOS window.

The programs CRYSON.EXE requires the same DOS-extender
as Crysol, namely, DOSXMSF.EXE (Phar Lap), and also
the font file COURB.FON to be in the current directory
or in the root directory C:\.

SGI version was compiled under IRIX 6.4, Fortran compiler 7.4

For the general information see file Crysol.ins in the Crysol
distribution file. The differences between Crysol and Cryson are:

(i) instead of the solvent density in e/A**3 required by
    Crysol, Cryson prompts for the D2O content in the solvent.
    The solvent density SD is then evaluated as

    SD = ROH2O*(1.- Y) + ROD2O*Y

    where Y is the D2O concentration (ranges from 0 to 1)
    ROH2O = 0.562 is the H2O scattering length density (10**10 cm**-2)
    ROD2O = 6.404 is the D2O scattering length density (10**10 cm**-2)

    The user may change the solvent density value manually.

(ii) if Y is not zero, Cryson prompts for the fraction of nonexchanged NH
    peptide DNEXCH. It is assumed that all exchangeable hydrogens (which
    belong to NH, NH2, NH3, OH and SH groups) are
    replaced by deuteriums in proportion Y, except for the main-chain NH
    groups, for which the probability is Y*(1-DNEXCH). Default value
    DNEXCH = 0.1 is generally accepted. The scattering length density B of
    any atom/atomic group at the D2O concentration Y is evaluated as

    B(Y) = B(0) + EXCH * Y * ( BD - BH ) * Afac

    where B(0) is the scattering length in H2O,
    BH = -0.3742 is the scattering length of hydroden (10-12 cm),
    BD = 0.6671 is the scattering length of deuterium (10-12 cm),
    EXCH is the number of exchangeable hydrogens in the group,
    Afac = 1-DNEXCH for the main chain NH groups, otherwise 1.

The scattering lengths and the number of exchangeable hydrogens are taken as below:

    Scattering lengths at 0%D2O (in 10-12 cm)

Number of exchangeable protons

- by default, Cryson searches for the contrast in the hydration shell in the range 0 < DroShell < 0.2*ABS(SD) [10**10 cm**-2]. For proteins in H2O and D2O, positive DroShell means more dense solvent in the shell, as seen from the figure below. One can, however, also imagine the situation when the positive DroShell would mean less dense solvent in the shell. The user can perform the search both in positive and negative ranges of DroShell, if necessary.