name attribute must be less than 64 characters Do not start names with "NX" (reserved by NeXus) names must start with a letter or "_" names must start with a letter or "_" names must start with a letter or "_" names must start with a letter or "_" names must start with a letter or "_" names must start with a letter or "_" names must start with a letter or "_" names must start with a letter or "_" names must start with a letter or "_" names must start with a letter or "_" names must NOT start with whitespace names must not contain a space names must not contain a "&" names must not contain a ">" names must not contain a "<" names must not contain a "!" names must not contain a "#" names must not contain a "%" names must not contain a "(" names must not contain a ")" names must not contain a "*" names must not contain a "+" names must not contain a "," names must not contain a "-" names must not contain a "." names must not contain a "/" names must not contain a ":" names must not contain a ";" names must not contain a "?" names must not contain a "@" names must not contain a "[" names must not contain a "\" names must not contain a "]" names must not contain a "^" names must not contain a "{" names must not contain a "|" names must not contain a "}" names must not contain a "~" /NXroot must contain at least one NXentry group NXentry must contain at least one NXdata group NXdata must contain one dataset with type="pArray" (image data) NXdata must contain a dataset with attribute "signal" must provide a "source" attribute for ND_ATTR must use type="ND_ATTR" when specifying a source Group needs a type="UserGroup" attribute NeXus group must have a "name" attribute