[Halla12_software] BaBar magnet yoke question (two more questions then my last email)

[Paul E. Reimer]

Hello Zhiwen,

> 1.
> I notice the there is a overllap between two parts of yoke just around
> the coil, as you can see from the lines of the am file
I'll have to look at this in more detail
>
> 2.
> for the cryo of the coil, there's the outer part made of Iron. It's
> not included in AM file. But I think it should because it will affect
> the field. Or is there other reasons to exclude it?
I don't know what the material is. 
> 3.
> Both PVDIS and SIDIS used Babar magnets in their first version of
> proposal, then used CDF in the second version. Why is the change?
> Maybe the reason was made clearer before I join in?
In fact, I was under the impression that Babar was used for the
acceptance of both detectors, while CDF was used for the engineering
report.  This was because we had engineering reports and access to the
CDF magnet at Argonne and our engineer's worked on this.  At the
proposal stage, since we were just dealing with a concept, that seemed
to work.
> 4.
> in SIDIS second version proposal, CDF yoke design was very similar to
> Babar design, only longer. What's the reason you design CDF yoke very
> differently now, Paul?
I spent more time looking at the field shape this time.  In particular,
I tried to obtain the same footprint for the detector area with minimal
magnetic field in that area.  In reality, the question goes back to the
detector designers--how much space to you need?  The other thing that I
did on the recent CDF design is to assume that the target is moved
forward in the magnet.

Paul

-- 
Paul E. Reimer                  reimer at anl.gov
Argonne National Laboratory     (630)252-4037
9700 S. Cass Ave.               (630)252-3903 (fax)
Argonne, IL  60439              (630)840-5708 (Fermilab)
                                (630)344-9207 (cell)
http://www.phy.anl.gov/mep/staff/Reimer_P_E.html

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