Calibration of Calorimetric Measurement in a Liquid Argon Time Projection Chamber

Round 1

Reviewer 1 Report

This is an excellent review article summarizing major effects that need to be considered for accurate calorimetric reconstruction in single phase LArTPCs. This work will be a very useful reference in the field. All the discussion and results presented are appropriately backed up with relevant citations. The work is nicely and clearly written. I therefore recommend this article to be accept for publication.

Author Response

Dear Reviewer,

Thank you very much for your review and positive comments.

Sincerely,
Tingjun

Reviewer 2 Report

The work is devoted to a brief review of the effects and methods involved in calibration of the measurement of the yield of ionization charge in LAr TPCs.
Although quite short, the paper describes to a good level of detalization all major effects, which take place between the ionization track and digitized signal.

Formation of the ionization in a LAr TPC is described in Chapter 2.
Chapter 3 describes the formation of the induced current on the TPC readout. Typical method of ADC calibration by injecting fixed charge is described first. In line 74 an example RMS of 5.1% of what is attributed to channel-to-channel response spread is given. However, the spread of the injected charge, always present in practical realizations, is not mentioned. It can be admitted that the spread may be negligible for particular case, but, it definitely deserves mentioning.

General form of the charge-unfolding deconvolution is given and described in details.

In Chapter 3.2 an ion mobility in comparison with electron mobility is shown. The latter depends on the drift field as it is mentioned later, but at that instance the corresponding field is not indicated. I recommend to add short reference like "@0.5 kV/cm".

Space charge effects are very well reviewed here. One caveat related to the ion space charge is, however, missing to my opinion. The J, average injected charge is a function of the recombination, and therefore, of the drift field. The field itself, as it is very well shown in the work, strongly depends on the amount of J. Having non-linear dependencies involved, the space charge distribution in space and time may in general show a variety of solutions, including non-stationary, and potentially, oscillatory. This aspect is not well studied yet, to my knowledge, so mentioning it in this work would be useful.

In Chapters 3.3-3.5 three principal phenomena, that affect charge during its drift towards anode are described. In Chapter 3.6 one of the "standard candles" for calorimetric  calibration of the TPC is shown - Stopping muon calibration. One more such "standard candle" - spectrum of Michel electron, originating from the same stopping muons would, probably, be worth mentioning too.

In general, the work represents quite complete review of the charge measurement calibration for LAr TPCs with a number of good references, and will for sure serve as a reference paper for people working in the field, and especially, students.

I recommend publishing the manuscript with minor review, where authors would take into account the comments given above, and minor specific remarks, listed below.

Specific remarks:

1. Line 65: in order to better define "A" add it in brackets: (pulse area A)
2. line 70 and formula below: Unit notation (ADC counts-tick) is confusing. It would look better with ADC*tick and square brackets:
g = 21.4 ke / 909.4 [ADC*tick] = 23.5 e/[ADC*tick]
3. Line 93 and below: free electron mobility of 500 cm2/V/s is given at a certain field. Indicate it as, for instance, "@0.5kV/cm"
4. Line 93 and below: "...space charge rho+, which we..." - add "density" for strictness - "space charge density rho+")
5. Line 145 "effective pitch" would be more precise "apparent pitch" or "measured pitch".
6. Line 172 and below: typo "double gridded ion chamber" => "double gridded ionization chamber"
7. Line 217 and below: "One of the Birks' model developed...". The Birks' model was rather adopted from a different field (scintillators), then developed by ICARUS collaboration. It turned out to work well also to describe quenching in charge.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf