sPHENIX MAPS tracker discussion

["Hao-Ren Jheng" <hrjheng AT mit.edu>]

Hi Grazyna,

Thank you for your comments. Please see my response below. 

——————————

My main concern is:

I am not sure that it is a good idea to complain about huge original background in the way you do in “Initial sample of Au+Au” window.

It sounds like complain against CAD and their performance, and this does not sound right. They are terrific. And BTW they fixed this background by closing collimator a bit. The start is usually difficult, it is normal. Please, ask Ming for the advice.

I think it will be enough if you say that the originally higher background was eliminated with the cut on cluster size. And this topic does not deserve the entire window.

I prefer to keep this section, for the following reasons:

1. This is one of the most critical issues for the MVTX and it has a significant impact on our plan for the first physics measurement, dNdEta.

2. This issue is mentioned in the commissioning status report [1], and it will be mentioned in the sPHENIX plenary talk and probably other presentations. I want to provide a consistent and detailed explanation of this issue in my poster.

3. I have been involved in the initial study of the beam background issue. I want to showcase the work that I have contributed to.

My intention is not to complain against or criticize CA-D, but to present the facts and the current situation. I hope I convey a positive tone by stating that “The MVTX group has been working closely with CA-D to understand and improve the beam conditions”, which emphasizes that this is a joint effort that both sides are committed to.

Abstract:

3^rd line:

….to be performed by sPHENIX concerns the charged-particle multiplicity, which  … ->... to be performed by sPHENIX is the charged-particle multiplicity, which …

Last line:

…will be discussed. -> … is discussed.

Thanks. Texts are modified.

Status of commissioning the MVTX:

More than 99.99 % … Why not 100%? (are there any pixels dead?)

to my knowledge all were active upon arrival to BNL

The number is quoted from the commissioning status report, which was approved last week on Aug. 25th.

Analysis:

point a:

I am not sure if I understand this:

... The vertex candidate Z position is calculated by linearly extrapolating the Z position of the constituent clusters in the tracklet to the beam …

Do you mean that you extrapolate line which connects the z coordinates (positions) of two constituent clusters? (your statement does not say it, it is my guess) or you mean something else ?

Yes, it is exactly how it’s done. 

——————————

Best,

Hao-Ren

[1] https://indico.bnl.gov/event/20373/attachments/49393/84311/Commissioning_Status_August_2023.pdf

On Aug 31, 2023, at 01:25, Grazyna Odyniec <g_odyniec AT lbl.gov> wrote:

Hi Hao-Ren,

A very nice poster.

A few comments for your consideration:

My main concern is:

I am not sure that it is a good idea to complain about huge original background in the way you do in “Initial sample of Au+Au” window.

It sounds like complain against CAD and their performance, and this does not sound right. They are terrific. And BTW they fixed this background by closing collimator a bit. The start is usually difficult, it is normal. Please, ask Ming for the advice.

I think it will be enough if you say that the originally higher background was eliminated with the cut on cluster size. And this topic does not deserve the entire window.

A few other remarks:


Abstract:

3^rd line:

….to be performed by sPHENIX concerns the charged-particle multiplicity, which  … ->... to be performed by sPHENIX is the charged-particle multiplicity, which …

Last line:

…will be discussed. -> … is discussed.


Status of commissioning the MVTX:

More than 99.99 % … Why not 100%? (are there any pixels dead?)

to my knowledge all were active upon arrival to BNL


Analysis:

point a:

I am not sure if I understand this:

... The vertex candidate Z position is calculated by linearly extrapolating the Z position of the constituent clusters in the tracklet to the beam …

Do you mean that you extrapolate line which connects the z coordinates (positions) of two constituent clusters? (your statement does not say it, it is my guess) or you mean something else ?

Thanks and best regards,

Grazyna



On 8/30/23 8:08 PM, Hao-Ren Jheng via sPHENIX-MAPS-l wrote:

Dear all,

I have updated my QM poster based on the feedback and suggestions during the plot approval today: https://sphenix-invenio.sdcc.bnl.gov/communities/sphenixcommunity/requests/4cba182a-7fd4-4b3f-b9dc-8267b282874a.

Please let me know if you have any further comments or questions about the updated version.

Best,
Hao-Ren



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