sPHENIX HCal discussion

[Edouard Kistenev <kistenev AT bnl.gov>]

HInner small tiles:

The fiber pattern on small tiles is from design made by Richie. It reflects the desire to keep all tile covered. Rather  complicated on rhomboidal tiles. The only purpose for further modifications to it would be to spread fibers apart at exit  as much as possible (by moving exit point to the center of the edge). The problem - comparing designs (manufacturing samples, scanning etc). Most likely the differences will be minimal except probably limited to  points like corners and fiber exits. Using beam may help to speed it.

HOuter large tiles.

The right-left asymmetry in muon signal measured in HB is worrisome. Most likely it reflects the fact that I missed the pattern modification made to bring both fiber ends together - pattern is very asymmetric right-left with respect to distance the light travels in the fiber. The proposal is to move the exit to the middle of the edge and to bring together two ends of fiber from right and left (option 1) or to cut the fiber into two parts and bring together 4 fiber ends. It is almost useless to discuss at this stage unless we have measurements to prove that such modifications are useful and doable (again - test beam may help). 

UNIPLAST agreed to help with this study free (no charge to BNL). Probably because the problem is common to sPHENIX and new project they just got. If we want more we’ll need a new development contract and … time.

Edward

 

On Mar 16, 2016, at 11:26 AM, Megan Connors <meganEconnors AT gmail.com> wrote:

Hi Edward,

To follow up with John's statement about the inclusion of the light blocks in addition to the new fiber configuration, I was wondering if we had tiles with light blocks with the old fiber design or the new fiber design without the light blocks to help decouple the two effects when comparing to the current tiles.

Best,

-Megan 

On Wed, Mar 16, 2016 at 11:19 AM, Lajoie, John G [PHYSA] <lajoie AT iastate.edu> wrote:

Hi Edward,

    This looks very interesting - I note that in addition to the modified fiber pattern they also incorporate the light blocks you had spoke about before.

    I don't recall much discussion about the fiber patterning - what is the goal of the new pattern? What deficiencies are there with the old pattern, and how will the beam test of the new pattern at FNAL be used to benchmark the new against the old?

John

On 3/16/2016 8:02 AM, Edward Kistenev wrote:

Attached are few pictures of tiles which will hopefully be available for beam testing at FNAL (towards the middle of the run). The three small tiles will have no/white/black paint over the  epoxy layer above fibers. Plans are also to produce three large tiles with modified fiber patterning proposed by UNIPLAST (tile manufacturer) to improve symmetry and uniformity of light collection. 

Edward

Edward Kistenev, PhD

PHENIX Physicist

--

John Lajoie

Professor of Physics

Iowa State University

 

(515) 294-6952

lajoie AT iastate.edu

Contact me: john.lajoie

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