sPHENIX EMCal discussion

[Joe Osborn <jdosbo AT umich.edu>]

Hi Anabel,

Thanks for sending this out and congratulations, it is a really nice paper and showcases many years of hard work in preparing for the construction of sPHENIX. Please find my comments below, most of which are just minor wording comments.

Thank you,

Joe Osborn

Is this paper going to IEEE like the 2016 paper or NIM-A (or somewhere else)?

Title - is there a way to differentiate this from the previous paper by e.g. mentioning that this EMCal is at large pseudorapidity and is 2D projective?

Similarly I think at least something along these lines should be mentioned in the abstract, that this calorimeter is 2D projective - just to differentiate it from the previous paper and not just give the impression that we are just trying to publish the same thing. Alternatively this could be mentioned at the beginning of section 2 or in the introduction (I see that Martin suggested similarly).

l 27 - remove “in order”

l29 - Suggest to reword to —> One such probe are collimated sprays of correlated particles, called jets, that arise from hard scattering interactions between two partons. 

l32 - Remove “Capabilities for heavy flavor measurements in”

l37 - “2pi azimuthal acceptance”

l39-43 - The phrase “calorimeter system” is used several times here, try rephrasing one to avoid the repetition. e.g. in line 40 you could say “sPHENIX will allow for the measurement of…” since the tracking system (not just the calorimeters) should also help us reconstruct jets if/when a particle flow algorithm is implemented

l101 - What does “working” mean? Transmission of light was normal, or good enough, or they were not physically defective, or something else?

l204 - I think this is the first time you mention the beam profile of 3.5 cm, maybe it would be worth mentioning in section 4 so that it is clear that this is part of the actual test beam setup and not just in the simulation.

l229 - regarded as -> considered

l245 - was done based on how the -> was performed based on how

l247 - vary depending -> depend

l248 - It might be nice to describe this figure in a little more detail here, in anticipation of the position dependent correction. For example, maybe by adding something like “Fig 6 shows that the energy response gets worse towards the tower and block boundaries” or something like that.

Reading further, it almost seems like section 7a could potentially be removed from Results and Discussion and integrated into the previous paragraphs. For example, the first paragraph of 7a could be integrated into lines 245-250, and the second paragraph of 7a could follow the discussion of the position dependent corrections. Although these are results, they could also be considered a part of the analysis of the data and showcase the need to account for the position dependence in the analysis.

l264 - “In the first one, the position was given by” -> “First, the position was determined by”

l265 - “for a total of 8x8 possible positions” - I think this was already mentioned earlier, may be redundant here.

l267 - given -> determined

l269 - Maybe mention here that the rest applies for both methods. E.g. “For each correction method, the position dependent calibration constants…”

l271 - remove “of the hits”

l274 - changed -> improved

l295 - Which position dependent correction is shown? Cluster determined or hodoscope determined?

l307 - error bars -> uncertainties

l321 - can come -> may be from

l322 - position resolution -> cluster position resolution

l341 - A prototype -> A 2D projective, large pseudorapidity, prototype

Since the simulation does not match the data, I assume this means that the simulation of the block boundaries needs to be tuned/tweaked. Maybe this is worth briefly mentioning, but also maybe not because the focus of the paper is on the test beam results and not on the tuning of the sPHENIX simulation to match the test beam data. 

Fig 7 caption - while the data points -> while the black filled points (or something similar) 

Fig 8 and 9 - sPHENIX preliminary should be changed to sPHENIX

Something that we discussed in the 2017 test beam analysis was removing the 8 GeV points from the linearity and resolution figures/results due to auto-correlations - the position dependent calibration constants were determined with these points, so there is some self bias there. I’m not sure if this was discussed or not with this analysis, but it is something to consider. For example, looking at the linearity plots in Fig 8 and 9, the 8 GeV E_cluster/E_input ratios (it looks by eye) are all exactly unity for each of the different colored options (tower 29 hodo/cluster, etc.). I could imagine a referee potentially asking about this.

I would remove “linearity and resolution for electrons” or move “resolution” from the linearity plot to the resolution plot - but the captions should adequately describe these figures. 

---------------------------------------

Joe Osborn

Visiting Scholar

University of Michigan

jdosbo AT umich.edu

(859) 433-8738

On Fri, Oct 25, 2019 at 9:52 AM Martin Purschke <purschke AT bnl.gov> wrote:

Hi Anabel,

Very nice. It shows how much work has gone into it, looks nicely polished.


I would move what the first sentence in Section II says earlier into the
introduction, and strengthen the message that this prototype is what we
will have at high eta, as opposed to the other one around eta = 0. This
will put this paper into better context with our earlier one that you
cite in passing as [19]. Then you can point out the differences to what
is described in the earlier paper. Some of this information is in the
final sentences of the introduction; I would weave this into a clearer
message. Given the long back-and-forth with the reviewers then it might
speed the acceptance up if we are up-front that this is a quite
different prototype.
Space permitting, you could add a drawing of a two-sector assembly and
point out what part was covered then and which part is tested now. Then
the right view of this prototype in Fig. 1 can be better put into context.

A really minor thing is about the sentence "Four veto detectors were
also placed around the EMCal in order to suppress background from MIPs."
I would not refer to them as MIPs, call this suppression of particles
traveling outside the beam position or so.

Another small latex-y thing is how you write word-subscripts such as
E_{cluster} in a formula. In math-mode, that is interpreted as factors,
c*l*u*.... Better to write E_{\rm cluster}. See if it looks better.

Best,
        Martin


On 10/24/19 21:13, Romero Hernandez, Anabel wrote:
> Dear all,
>
> I've put together a draft of the EMCal test beam paper with help from
> Anne and Tim. Comments and suggestions are welcome! In order to keep
> momentum on this going, please try to send your comments as soon as
> possible.
>
> Best,
> Anabel
>
> _______________________________________________
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>


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Martin L. Purschke, Ph.D.        ;   purschke AT bnl.gov
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