Hi there, I am applying for PhD's and was wondering if the PhD that you do limits the jobs that you can apply for.

For example. If I was to do a PhD in medical physics, would it stop me from applying for jobs in astrophysics or would it not matter?

Cheers,

as long as you have the skills for the job - post docs are more about what you can do - although I do know some who have taken on entirely different fields

My two penneth: I've seen a lot of job adverts that state the candidate needs (say) three years' experience of cell culture, or enzyme assays. You may be able to get a job in a different field, but it may not be at a very high level.

I find it hard to believe that a PhD in medical physics would be suitable for a job in astrophysics, but hey, what do I know. Skills, especially technical and experimental skills are generally transferable.

You can transfer between some fields relatively easy but not between others. In Physics some fields are significantly harder to get into than others and post doctoral positions are harder to find. For example, astrophysics is a tough subject to get into - there's a lot of competition. This could be due to how much funding there is available. Geophysics, on the other hand, is a lot easier to get into. This is probably because of the sheer amounts of money available thanks to all the oil and gas companies.
You *may* be able to transfer over to Astrophysics if you're coming from a field of Biophysics where you worked mostly on computer simulations and you were going to an area of Astrophysics that's mainly based on computer simulations. Otherwise it'd be pretty tough.

Have you already got a place in a different field and are having second thoughts?

I'm not having second thoughts as such. I was using the astro/medical thing as an example. I have been offered a PhD in condensed matter physics which is about semiconductors/vacuum systems etc. However, I have also been offered a PhD in an astrophysics, which is all about developing computer simulations etc. I don't really like the supervisor on the condended matter PhD, but the topic sounds really good. I think i'd have a really good time on the astro PhD - great supervisor and interesting/easy topic. I'd really like to go into inductry when I finish my PhD possibly doing research and development and generally using building stuff. This is the problem though, as the condended matter PhD would give me all the experience I need whereas the astro one would not. What do you think?

Cheers

Tough choice, but if you are really sure about going into industry then obviously the one that will give you the most appropriate skills would be the sensible choice. But I can definitely see the lure of astrophysics. I'd find that hard to resist myself.

I think someone else said this earlier, but it's not the subject of the PhD that's important, it's the skills that you take out of it. If you're doing an astrophysics PhD that allows you to learn the skills necessary in a role in contendede matter (whatever they might be!!) you would be fine.
It's also important to realise that coming out with a good PhD in a related field is probably better than coming out with a mediocre PhD in the field of interest. If you think you'll enjoy the astrophysics Phd and come up with better standard work than in the other, it might be worth thinking about.
If I were you, have a chat with someone in the field, and see what they suggest...