Source space of MSR

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I'm trying to track down an external source of noise with our MEG system.
To that end, I'd like to build a source space of evenly spaced dipoles with
free orientation, spanning an area approximately the size of the MSR.
Hopefully inverting the data onto this space within the frequency band of
the noise could give me a clue where it's coming from.

Is there a straightforward way to do this in MNE-Python without hacking a
lot of low-level functions?

Jeff Hanna
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External Email - Use Caution

You probably want to set up a "discrete" source space, like:

mne.setup_volume_source_space
<https://www.martinos.org/mne/stable/generated/mne.setup_volume_source_space.html>(pos=dict(rr=...,
nn=...))

You need to specify `rr` in meters in the MRI coordinate frame. (You can
make the MRI, MEG, and head coordinate frames identical to make your life
easier, too.) The `nn` won't really matter as long as you use `loose=1.`
when computing the solution.

For the `rr` you could use a sphere around the MEG helmet. You can use the
private (meaning it could stop working at any time!)
mne.surface._get_ico_surface(5)['rr'] to get a unit (1 meter radius)
sphere, for example, and scale and/or shift these points as you see fit.

Eric