The best MCNP manual for your needs will depend on your level of experience with the software and your specific application. It is recommended to start with the MCNP Primer, which provides a comprehensive introduction to the software. From there, you can consult the other manuals for more specific guidance.
Yes, there are several free MCNP manuals available online. The MCNP Primer, as well as the MCNPX User's Manual and MCNPX Primer, can be downloaded from the Los Alamos National Laboratory website. Additionally, many universities and research institutions have made their own MCNP manuals available online for free.
This is a matter of personal preference. Both physical and electronic copies of the MCNP manual are available for purchase. However, keep in mind that electronic copies may be more convenient for searching and referencing specific topics.
MCNP manuals are typically updated every few years, with new versions and revisions being released by Los Alamos National Laboratory. It is important to check the publication date of the manual you are using to ensure you have the most up-to-date information.
In general, it is recommended to use the MCNP manual that corresponds to the version of the software you are using. However, many of the basic principles and techniques outlined in older versions of the manual are still applicable to the latest version of MCNP. It is always best to consult the most recent version of the manual for the most accurate and up-to-date information.