[Halld-tagger] goni resolution

[Richard Jones]

Hovanes,

Rather than obsolete I would say, "in need of review".  That is the correct order of magnitude, but it needs to be reviewed.  One microradian is overkill and 10 microradians is marginal.  I would be willing to stand and defend the 5 microradian number at this point, because it is the natural width (FWHM) of ideal diamond 2,2,0 so it sets a scale below which one is not very interested.  But we all need to sit together and review it with the arguments in front of us.

Of course step size is not the same thing as accuracy.  Reproducibility is a related spec, but not the same as step size.  One of us needs to put all of the arguments for target angle resolution together on one wiki page, in preparation for that discussion.  Is that something you would be prepared to do?

-Richard J.


On 11/29/2011 10:18 AM, Hovanes Egiyan wrote:
> Hi Richard,
>
> Is Table 4.2 in the Hall D CDR obsolete or these are our current specs?
> The specs for
> the angular precision there are 10urad, which is 0.57x(10^-3 deg), about
> factor
> of two better than the number for the Mainz goniometer. I think
> the number you gave during the last meeting was 1 arcsecond, which
> is 4.8urad, which is factor of ~ 2 better than the spec in Table 4.2, and
> factor of  ~3.5 better than the Mainz spec.
>
> I am pretty sure that Ken is working with an assumption that 17 urad is
> enough for
> GlueX. If we want better step size then we probably should let him know
> about it.
>
> Hovanes.
>
>


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