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

[Zhiwen Zhao]

On 02/09/2011 10:30 AM, Paul E. Reimer wrote:
> 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
Eugene answered this. one of them is commented out in am file, I will 
correct it in geometry file.
>>
>> 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.
shape	materiel   inner	outer	half length
Tube	Iron 	   142.  	177.  	192.5
Tube    Air        147. 	172.  	187.5
Tube	Al	   152. 	154.  	175.0
>> 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.
refer to Xin's reply
>> 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.
Besides the two end cups, the middle part of the yoke are different.
Are those middle part come with magnet so we can't really modify them?
BaBar design has many more details in the middle part which I think 
Eugene did it not only for field but also engineering concern. Do want 
CDF to take advantage of that?
>
> Paul
>
Zhiwen