Prefactor calculation when there are both P(Q) and S(Q) (Trac #1259)

[sasview-bot]

The models for vesicle and sphere systems ( P(Q) ) with the hard sphere interaction ( S(Q) ) have two volume fraction: phi_PQ and phi_SQ.
phi_PQ is the volume fraction from the form factor.
phi_SQ is the volume fraction from the structure factor.

Based on the testing of the two models, the prefactor of the scattering intensity is currently set up to be proportional to scalephi_PQphi_SQ.

If the scale is set up to one, the prefactor with the absolute intensity should be proportional to phi_PQ only.
It should not be phi_PQ*phi_SQ.

It is suggested to remove phi_SQ from the calculation of the prefactor.

Migrated from http://trac.sasview.org/ticket/1259

{
    "status": "new",
    "changetime": "2019-03-26T10:22:38",
    "_ts": "2019-03-26 10:22:38.069970+00:00",
    "description": "The models for vesicle and sphere systems ( P(Q) ) with the hard sphere interaction ( S(Q) ) have two volume fraction: phi_PQ and phi_SQ. \nphi_PQ is the volume fraction from the form factor.\nphi_SQ is the volume fraction from the structure factor.\n\nBased on the testing of the two models, the prefactor of the scattering intensity is currently set up to be proportional to scale*phi_PQ*phi_SQ.\n\nIf the scale is set up to one, the prefactor with the absolute intensity should be proportional to phi_PQ only. \nIt should not be phi_PQ*phi_SQ.\n\nIt is suggested to remove phi_SQ from the calculation of the prefactor.\n",
    "reporter": "yunliu",
    "cc": "richardh",
    "resolution": "",
    "workpackage": "SasModels Model Issues",
    "time": "2019-03-26T10:13:25",
    "component": "sasmodels",
    "summary": "Prefactor calculation when there are both P(Q) and S(Q)",
    "priority": "minor",
    "keywords": "scale",
    "milestone": "SasView 5.0.0",
    "owner": "yunliu",
    "type": "enhancement"
}

[sasview-bot]

Trac update at 2019/03/26 10:16:46: yunliu changed attachment from "" to "TestResults-SphereVesicles-SASView.docx"

[sasview-bot]

Trac update at 2019/03/26 10:21:09: yunliu changed milestone from "SasView 5.1.0" to "SasView 5.0.0"

[sasview-bot]

Trac update at 2019/03/26 10:22:38: yunliu commented:

Forgot to mention that the prefactor calculation is the same for both V4.1.2 and V5.0.