Scattering characteristics of both are expected to be different by two techniques i.e. X rays and neutrons
The xray scattering cross section is essentially proportional to Z^2. Therefore the signal will be largely dominated by scattering from heavy atoms. In contrast the neutron scattering cross section varies from element to element. You can get an overview of scattering cross sections for thermal neutron energies at https://www.nist.gov/ncnr/planning-your-experiment/sld-periodic-table .
Since xrays scatter strongly from electrons it carries information about a scattering volume at the surface which is determined by the energy-dependent penetration depth. Neutrons interact weakly with matter and unless your sample contains some strongly absorbing element like cadmium or boron will probe the bulk of the sample. Also xrays can be focused onto a tiny scattering volume and can often give a lot of information from tiny samples. For neutrons usually large samples are needed to get a decent signal.
These are the most obvious general differences. Depending on your specific project other qualities can become relevant. What are you planning to do?
A comprehensive source of information on xray, electron and neutron scattering is volume C of the international tables on crystallography. (https://it.iucr.org/C/)
Also, the absence of scaling with the size of the electron cloud makes neutrons sensitive to different isotopes of the same element (with the possibility to implement isotopic-substitution experiments) or different atoms with similar Z’s (case in point: adjacent transition metals). The variation in neutron scattering length is also independent of the momentum transfer Q, which means that,
unlike the X-ray case, no hurdle is encountered at large Q-values with no severe
limit on the information content from data, especially when Fourier transforms are
calculated.
Further, neutrons enable the study of nuclear-spin correlations, due to the interaction of the neutron magnetic dipole moment with non-zero spins of some nuclei.
Simon and Alexandra both have correct things to say. I just want to emphsize something implicit in their answers. The fact that x-ray scatting is from electrons butneutron scattering is from nuclei; also x-ray scatting intensity is proportional to the atomic number squared (Z^2) but neutron scattering intensity depends on the isotope in a non-obvious way. The implication that is very important to whole branches of science is that x-ray diffraction signals are insensitive to hydrogen atoms; neutron diffraction experiments (expecially with deuterated samples) can have very good sensitivity to hyrdogen atoms. If you have a compound that contains hydrogen and you want to determine the crystal structure, XRD may suffice if you can deduce where the hydrogen atoms reside from where everything else is, but if you can't deduce if from other considerations or your want to measure the hyrdrogen atoms locations, neutron scattering experiments can be indispensible. Thus, neutron scattering is widely used for biological samples and for polymers.
Also, for experiements where very low q is needed (that is very large d-spacing), very low scattering angles are needed, or longer wavelengths. Long wavelength x-rays (such as 4 keV, from a Ti anode) need hardly penetrate sufficiently to penetrate through x-ray source windows and detector windows (or air), so have limited value. I don't know of any conventional x-ray tube with lower Z than Ti. Maybe you can get lower angles and lower energies at specialized facilities, such as national lab synchrotrons. But to look at really low q, you want ≥ 1 nm wavelength neutrons; they can be created by cold moderator and they will still penetrate significanly through samples. So neutrons excel for very low q experiments (SANS = small angle neutron scattering).
- Badges
- Science topic
- Similar topics
- Chemistry
- Nanotechnology
- Nanostructures
- Thin Films