sPHENIX HCal discussion

[Stefan Bathe <bathe AT bnl.gov>]

Hi John,

I just answered most of your questions in my other message.  But let me 
repeat here:

> On Jun 14, 2019, at 9:58 AM, Lajoie, John G [PHYSA] <lajoie AT iastate.edu> 
> wrote:
> 
> Hi Stefan, 
> 
> Awesome!
> 
> A few more detailed questions that can't be determined from the photographs 
> - 
> 
> 1) How snug were the tiles? Any problems? 
You mean in terms of thickness?  No issue whatsoever!  (Of course we only 
tested one gap, and the gaps vary.  But we check all gaps with the gap gauge 
when the sectors arrive.  So I’m confident there will be no issue here.)  

> 2) I seem to recall we were planning to some sort of foam spacer at the end 
> of the tiles to help them stay centered in the gap. Was this also 
> implemented, or am I remembering this wrong. 

We discussed this again yesterday as we went along.  But we don’t have this 
in hand yet.  (This is to fill out the empty triangle that arises between the 
straight edge of the sector and the diagonal edge of the last tile, to make 
sure the tiles don’t fan out in the front where there is no clip to hold 
them).  I still think this is a good idea.  Richie thinks it’s a lot of 
material, and in principle not necessary since the front edge of the tiles 
lines up with the front edge of the steel, and therefore the tiles can’t 
pivot.  The line-up is not perfect.  So there is a small gap, allowing for 
some pivoting.  But we plan to fill this gap with a strip of foam.  As I 
said, I still think we should put a filler into that triangular space.  This 
way we just avoid any issues with creating gaps between the tiles.

> 3) How snug were the tiles laterally? We've been a bit worried because the 
> shape measurements with the cardboard templates might not be very 
> indicative with the wrapped tiles and they could be a bit snug laterally. 
> 
It worked very smoothly.  We started from the center and worked our way out 
to the edges, just nudging the tiles to each other one by one as we installed 
them with a long cardboard strip (we will use wood in the future).  There was 
no issue whatsoever getting the last tile in, and there was no gap whatsoever 
at the end.  Couldn’t have been better, I’d say.  (There is some wiggle room 
that comes from the not perfectly tight wrapping of the tiles, I think, which 
made it appear just perfect.)
As I said in my other message, we did not install the clips (waiting for 
hardware).  I’m confident the holes will lign up.  But this needs to be 
confirmed with an actual test, of course.

Regards,
Stefan


> Thanks to the group that completed this!
> 
> John
> 
> -----Original Message-----
> From: sPHENIX-HCal-l <sphenix-hcal-l-bounces AT lists.bnl.gov> On Behalf Of 
> Stefan Bathe
> Sent: Friday, June 14, 2019 12:10 AM
> To: sphenix-hcal-l AT lists.bnl.gov
> Subject: [Sphenix-hcal-l] First fit of all 24 tiles into a single 
> gap--success!
> 
> Dear All,
> 
> This afternoon a bunch of us made sure that we can actually fit all 24 
> tiles into a single gap of an outer HCal sector along eta.—It worked!
> Here are some photos for your enjoyment:
> 
> https://urldefense.proofpoint.com/v2/url?u=https-3A__photos.app.goo.gl_wWNGACoDgLHuLhgz9&d=DwIGaQ&c=aTOVZmpUfPKZuaG9NO7J7Mh6imZbfhL47t9CpZ-pCOw&r=3Kef6foBA0XguSdT48aDjQ&m=KsYSgX3zoDTcdYNe_UW9CPwzhTGVEsUISp2D8w-mA0c&s=KwjCJWigVYf_Nq9gz92GfHUTaS_YHlfcTxnKcPu_kjo&e=
>  
> 
> Regards,
> Stefan
> -- 
> ---------------------------------------------------------------------------------
> Stefan Bathe
> Professor of Physics
> Baruch College, CUNY
> 
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