A senior scientist at a research company recommended me for a position in both his research group and another research group. I am also applying at other companies, and these require references. Would it be disingenuous to ask for him to be a reference for positions at different companies?
Is it ok to have a reference who recommended me for one job be a reference for another job?
You absolutely can and should use both . It is not only appropriate it is also what is to be expected.
If you are not sure, it's a matter of common courtesy to ask your senior scientist instead of asking us, who are totally irrelevant to your situation.
I don't know why it's so challenging to you to ask your scientist "Will you act as my reference?"
Not a problem and it's pretty standard. Make sure you let your reference know though, so they aren't surprised when they suddenly get a call from company X when they only knew about company Y.
"Hey, just so you know, I'm also applying for a job at company Y. I hope you don't mind if I use you as reference for this aswell? The job description is here . Pretty similar as the first one, but this includes project management as well, so if they call, I'd appreciate if you mentioned the time I worked as scrum master."