Re:

[Elton Smith <elton@jlab.org>]

Hi Pavel,

Thanks for your prompt response. Yes, we have considered addition vertical
bend magnets. These also complicate issues related to background due to
the bremstrahlung tail, fail-safe operation; also our belief is that the
neutron background will be reduced very little. The electromagnetic
background is still a question, but generally another magnet may very well
enlarge the aperture into the tagger building which needs to be shielded.
Also for a small angle, I don't know how effective it would be.

Elton.

Elton Smith
Jefferson Lab
elton@jlab.org
(757) 269-7625

On Fri, 7 Jul 2000, Pavel Degtiarenko wrote:

> Hi Elton,
> Have you considered/rejected the idea to use the second magnet in the middle
> of electron beam dumpline, which would solve the two problems: (1) place the
> dump back under ground and (2) eliminate the direct line of sight for the
> backscattered photons and neutrons at the tagger.
> However, I do not see a Big problem to have the dump placed above ground with
> a proper shielding.
> Regards,
> Pavel
> 
> Elton Smith wrote:
> 
> > Hi Pavel,
> >
> > There has been considerable discussion about the difficulties of properly
> > aligning the phase space of the beam if we incline the tagger magnet
> > relative to horizontal. Therefore, our current feeling is that we should
> > not incline the magnet plane, which means that the electron beam dump will
> > be above ground along with the rest of the beamline. Please let me know if
> > this presents issues which cannot be address with proper shielding.
> >
> > Thanks, Elton.
> >
> > Elton Smith
> > Jefferson Lab
> > elton@jlab.org
> > (757) 269-7625
> 
>