Hadron-Induced Radiation Damage in Fast Heavy Inorganic Scintillators

Round 1

Reviewer 1 Report

In this paper, the radiation damage of several fast heavy crystals, LYSO, BaF, PWO and LuAG, were studied using protons and neutrons.

The results showed that before and after proton and neutron irradiation, the light yield of LYSO and BaF crystals decreased to 85% and 75%, respectively, and the light transmittance performance remained good. At this point, PWO crystal is much worse. The RIAC parameter of the crystals under different irradiation doses were compared. LuAG crystal showed better radiation resistance than LYSO and BaF.

 

I think this result is very important, especially for the construction of the next generation large collider experimental spectrometer. It deserves to be published

 

Author Response

The Authors thank the reviewer for the comments.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript reports on the radiation damaged induced in inorganic scintillators by protons and neutrons. The materials tested are LYSO and PWO crystals, and LuAG ceramics. These are candidates for timing layers and calorimeters at future colliders thanks to their fast timing capabilities and testing their radiation hardness is of paramount importance. Therefore, the study is novel and valuable for the community and should be considered for publication.

 

However, the manuscript has some minor methodological issues which must be cleared, as well as a few small corrections that would improve its value, and I suggest a revision.

 

Here follow my comments:

 

-) Line 25: several members of the community prefer using Gy as units to rad. Adding the value between brackets in GGy could be a helpful quick addition.

 

-) Line 64: I suggest to give the beam size (2.5 cm) in mm for coherence, since all the other sizes are given in mm.

 

-) Fig. 1: some text in the figure is slightly difficult to read. Moreover, mentioning in the text how the theoretical limit of transmittance was computed could be useful for some readers.

 

-) Fig. 1: The EWLT is a valuable tool to quantify the loss in transmission. However, the values reported have no uncertainty quoted. Is the precision down to the 0.1% level? If not, statistic and systematic uncertainties must be evaluated and stated.

 

-) The surface state of LuAG ceramics is not discussed, and the absence of transmission plots (along the line of Fig.1) for this material does not give hints on the surfaces state. Rough surfaces can significantly deteriorate transmission values and introduce systematics in RIAC estimation. The topic must be discussed and clarified, especially to claim that LuAG RIAC is lower than LYSO (line 147).

 

-) Line 108: 77% loss in light output might affect the performance of some detectors significantly. It is not possible to qualitatively state that LYSO and BaF2 are radiation-hard. The sentence should be modified, e.g. along the line of lines 94-95.

 

-) Fig. 2: some text in the figure is very difficult to read.

 

-) Fig. 2: some points are unclear with the light output fit results. No errors are given on the fit parameters and must be added. For instance, the tau parameter of the fit function is linked to the scintillation decay time, hence currently the manuscript claims that the decay time of all the materials is affected by the irradiation. Is that the correct message? If instead the values of tau were within errors, are the parameters A1 and tau correlated? If so, a change in tau would affect A1 and it would therefore be better fixing tau during the fit.

Moreover, it would be beneficial discussing the meaning of the parameters A0 and A1. Why in the plot is shown the LO at some gate, instead of e.g. A0+A1?

 

-) Line 113: the EWRIAC is not mentioned before and must be defined. Is it the Emission-weighted RIAC?

 

-) Figure 3: I suppose the L parameter is the mean light path length. It is worth adding it to the text (e.g. in line 119).

 

-) Line 130: the sentence has two verbs and it seems like there was a mistake. I would suggest to rephrase it.

 

-) Line 130 and 132: The proportionality factors between RIAC@430nm and proton and neutron fluence, and especially their difference, are very interesting results but the uncertainties must be evaluated and stated.

 

-) Line 135: from my understanding the RIAC@430nm of Fig. 4 include values from experiment at CERN PS-IRRAD.  If so, the statement “[…] is a factor of ten less than that by 800 MeV protons” is not fully correct and should be adjusted.

 

-) Fig. 5: some text in the figure is very difficult to read.

 

-) Fig. 6: the caption discusses the RIAC but the plot y axis is light output.

Author Response

The authors thank the reviewer for careful reading and comments.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The comments have been addressed and the manuscript can be accepted for publication.