New term request: Compton Scattering

[spc93]

New term label (required)

compton scattering

Definition (required)

A form of deep inelastic x-ray scattering, typically involving the kinematic excitation of a single electron and providing information about the initial electronic momentum.

Position in the hierarchy or the parent class (required)

Subclass of: http://purl.org/pan-science/PaNET/PaNET01182 (inelastic x-ray scattering)

Synonyms

None

Cross-references

https://en.wikipedia.org/wiki/Compton_scattering

[hgoerzig]

@spc93 just for understanding. is there any useful way of creating two/three parent classes. One would be the inelastic scattering and the other kinematic excitation of a single electron. Could the latter be either a experimental physical porcess or a functional dependency? Or defined by purpose: providing information about the initial electronic momentum?

[spc93]

Yes - this is very important, as you suggest. The terms can be given multiple superclasses in the spreadsheet.

[paulmillar]

If I remember correctly (and read the Wikipedia article correctly), Compton scattering could involve either gamma rays and x-ray.

So, should we have a wavelength-agnostic term "Compton Scattering" node (child of "inelastic scattering") with a subclass "X-ray Compton Scattering" (child of "Compton scattering" and "x-ray scattering")?

[spc93]

Good points! Stating with @hgoerzig second point, which I didn’t comment on. The problem here is that there are inadequacies in the precision of current naming conventions. We would probably need a new definition for this. Compton scattering typically has measurement of initial momentum as a purpose, but not always. I think our project is to take existing definitions that are ‘understood’ by the community and formalizing them, rather than making up new definitions. If there existed a technique ‘Compton scattering for electron momentum studies’ then we could formalize it. On x-rays and gamma rays, these are the same and are distinguished by (1) the tendency for gamma rays to be higher in energy and (2) for gamma rays to be emitted by nuclei and x-rays by atoms. Historically, we have referred to high energy synchrotron photons as x-rays, but we could (and possibly should) have called them gamma rays. So I think within the PaN domain, there is no need to make a distinction. However, this is quite extensible. We could, in the future, include techniques with a gamma-ray probe (radioactive source) and then create and create gamma-ray Compton scattering. Perhaps a more relevant (to PaN domain) question relates to deep inelastic neutron scattering, sometimes referred to as neutron Compton scattering. But I would argue that this is a different thing.

[spc93]

Replying to @hgoerzig : is there any useful way of creating two/three parent classes. One would be the inelastic scattering and the other kinematic excitation of a single electron. Could the latter be either a experimental physical porcess or a functional dependency? Yes, we can make Compton scattering a subclass of 'inelastic x-ray scattering' and also of 'kinematic excitation of a single electron'. It would need some work and more terms, e.g. defined by experimental physical process excitation technique electron excitation technique single electron excitation technique kinematic excitation of a single electron technique

or something similar. We could then use some of these terms as additional superclasses of existing terms, giving them a slightly richer definition. So I think it makes sense but requires quite a lot of work so I would be inclined to keep it simple for now, focussing on what we need for catalogue searches. (In fact, there is also two-electron Compton scattering, but that is another story...).

Or defined by purpose: providing information about the initial electronic momentum? Yes we could, and this is mostly true, but not always. For example, there are imaging techniques based on Compton scattering where the electron momentum is not probed.

[hgoerzig]

@spc93 are excitation techniques maybe used in other techniques? The experimental physical process 'excitation techniques' on a high level might be worth it to be created. We should be able in the future to put a classes between a class and its subclasses. I mean 'kinematic excitation of a single electron technique' should stay a subclass of 'excitation technique' even if we put something inbetween and delete the direct subclass relation. Or would there be a conflict in the versions of the ontology? Just wondering how this with the inheritance of ontologies works.