[Frost] draft of nstar

[Christopher Keith]

Natalie,
Eugene's description of transferring the butanol beads from storage in 
LN2 to the FROST refrigerator is correct.

I would also edit the bottom two bullets on that slide, describing the 
magnets.
-- Target sample is dynamically polarized at 250 mK using an external 5 
T solenoid;
-- An internal racetrack coil (0.5 T) is used to rotate and hold the 
polarization transverse to the electron beam during data acquisition;

Chris


On 5/22/13 9:54 PM, Eugene Pasyuk wrote:
> Hi Natalie,
>
> Looks good.
> I have a few suggestion for your slides.
>
> Slide 9: "Butanol: C4H9OH dripped into LN2 bath and then cooled down very low to <1K and LN2 is replaced by LHe
> bath" This is a bit confusing. If you want to describe how the target was prepared, then it goes like this.
> Butanol doped with TEMPO dripped into LN2 bath where droplets solidify into bids. They were kept in LN2 until the in-beam cryostat is cold and ready to be loaded with target material. Butanol bids were loaded in to the target cup which is still kept in LN2. At this time LHe is removed from the mixing chamber, cryostat is open. The cup with butanol bids is taken out from the LN2 and quickly inserted in cold but empty mixing chamber. Then cryostat is closed, pumped and filled with 4He and 3He mixture and cooled down. After that it is ready to be polarized.
> However, I think these details probably are not necessary for this presentation.
>
> slide 10: Don't use terms like GPID, EVNT, Tpho. Nobody outside of CLAS knows what it means and will cause unnecessary questions which will require lengthy answer. Just describe event selection in terms of physics variables (time, velocity, momentum, mass etc.) I also don't quite understand statement: Protons and kaons fall nicely in
> opposite sectors. Why do you exclude events where pi- may be detected?
>
> slide 11: you may want to define on this slide what is delta beta which you use. Something like difference between measured and calculated velocity. You can write equation. You may be asked why the momentum cut off for protons and kaons is 400 MeV/c.
>
> slide 12: Define what are the missing mass you compute. You have different missing masses on different plots. Also define what is M_det. Titles on the plots are confusing
>
> slide 14: some of the equations in white boxes look fuzzy.
>
> slide 15: for the plot with missing pion mass use missing mass squared to avoid problem with negative. Titles on the plots also confusing.
>
> slide 17: Legend is incomplete. This is important slide which shows you results. Use large symbols for CLAS data so that they stand out form everything else on the plot. Same for 18 and 19.
>
> -Eugene
>
> ----- Original Message -----
>> From: natalie at jlab.org
>> To: frost at jlab.org
>> Sent: Wednesday, May 22, 2013 2:32:05 PM
>> Subject: [Frost] draft of nstar
>>
>> Hi all,
>> I am out of the country right now, so haven't been able to attend the
>> past
>> few meetings. However, here are my draft slides for Nstar for my
>> invited
>> talk. One slide is blank because I am rerunning the data, but it will
>> be
>> filled out by the time I email the hadron group. Please let me know
>> if you
>> have any comments or suggestions.
>>
>> http://www.jlab.org/Hall-B/secure/g9/natalie/nstar13.pdf
>>
>> Thanks,
>> Natalie
>>
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>>
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-- 
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Christopher D. Keith
Jefferson Lab               email: ckeith at jlab.org
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