If its an integrated MS/PhD, seven years doesn't seem long for experimental science. If you already have an MS, which normally takes two years, then its maybe another 4-5 years.
At least in Princeton experimentalists do complete integrated MS/PhD within 5 years. Having a separate MS is atypical for American-educated students, plenty of schools (all the top schools IIRC) don’t even have a program, the MS is only offered as an incidental degree of the PhD program.
