sPHENIX MAPS tracker discussion

[Anthony Frawley <afrawley AT fsu.edu>]

Hello Ming and All,

Regarding the item in the review charge "Status of the simulation to optimize the MVTX and INTT for tracking in sPHENIX and timescale for its completion", we will have to agree on what we mean by "optimize the MVTX and INTT for tracking". We should do this ASAP.

I will not be available to call into the EC meeting tonight, so let me comment now.

The roles of the MVTX and INTT in sPHENIX are largely orthogonal, and therefore so is their optimization.

The role of the MVTX is to measure the track DCA using three high resolution space points that are matched to the track from the TPC and INTT. I think it would be hard to argue that we need to optimize the present MVTX design further. What we have is essentially what ALICE intends to build after careful consideration on their part, and what we have simulated extensively in sPHENIX - and found to work very well. We could consider dropping back to 2 layers of MVTX, but I think that would be extremely hard to justify. The reasons for choosing 3 layers are clear and compelling.

The primary role of the INTT is also clear - it adds space points to a track that can only come from the triggered beam crossing. It will also provide several precise space points in the r-phi plane between the MVTX layers and inner TPC, which may turn out to be important when we have to deal with space charge effects. Presently, in simulations we seem to be able to track adequately in high luminosity Au+Au without the INTT. I would not be willing to bet the ranch that this will be true in real life.

It is in p+p collisions that the INTT will likely be crucial. There we expect the TPC to contain hits from 340 collisions at any given time, and the MVTX to contain hits from approximately 130 collisions. The ability of the INTT to resolve a beam crossing will eliminate all but the collisions from the beam crossing of interest (1.3 events on average). 

We do not yet have full tracking simulations for high luminosity p+p. I think that to really evaluate how the INTT performs versus number of layers we will need to address that.

Best regards

Tony

---

From: sPHENIX-MAPS-l <sphenix-maps-l-bounces AT lists.bnl.gov> on behalf of mxliu <ming AT bnl.gov>
Sent: Wednesday, June 27, 2018 12:19 PM
To: sPHENIX-MVTX; sPHENIX LDRD
Cc: Mickey Chiu; Ross Corliss; Rachid Nouicer
Subject: [Sphenix-maps-l] July 19-20 MVTX Directors Review preparation

 

Hi all,

As you know, there will be a MVTX Directors Review July 19-20.

I have put together documents and slides for the reviews,

 

Review charge and preliminary answers,

https://www.phenix.bnl.gov/WWW/publish/mxliu/sPHENIX/Reviews/BNL-072018/sPHENIX-MVTX-Review-Charge-Answers-062018-v1.pptx

 

and my draft overview slides,

https://www.phenix.bnl.gov/WWW/publish/mxliu/sPHENIX/Reviews/BNL-072018/MVTX-Overview-BNL-DirectorsReview-07192018-v1.pptx

 

I will also post others’ slides there once available.

 

 

John Haggerty will chair an internal dry run on July 9^th , mark your calendar!    

 

Cheers,

Ming

 

-- 

Ming Xiong Liu

P-25, MS H846                     TEL:505-667-7125 

Physics Division                             631-344-7821(BNL)

LANL                                               630-840-5708(FNAL)

Los Alamos, NM 87545      FAX:        505-665-7020