https://indico.ihep.ac.cn//event/8183/

First,Ryuta introduced gain homogeneity and radiation effects of Low Gain Avalanche Pad Detectors briefly. Next, he answered other’s questions.

Xin: Could you elaborate the two proposed reasons for the gain degradation in LGAD devices? Ryuta: Measurements on LGAD samples with leakage current in the range of few μA showed that the voltage needed to deplete the multiplication layer after irradiation decreases. This effect was associated with an acceptor removal due to the removal of boron in the multiplication layer which would also explain the observed gain degradation. An alternative explanation for the gain degradation in LGAD devices is based on the simulation of LGAD structures which showed that the effect could be caused by charge trapping in the device.

Yuhang: The reason about comparing the results for neutron and proton irradiation but also with previous measurements in the fluence range below 10^15 neq/cm^2 showed that the effective acceptor removal works faster for charged hadrons. Ryuta: This is one of hot topic for the study of radiation damage, and one of summary of this paper.

Suyu: We can easily see the influence on the gain of the devices, but what can we learn for intrinsic charge multiplication? Ryuta: From the histograms in the paper, the decreasing of the gain by the multiply layer & the other part is not clearly separated.

Amit: What is the guard ring structure in the design and why due to the absence of a guard ring structure in the design, it is impossible to distinguish surface from bulk current contribution? Ryuta: I was trying to find out the schematic for the guard ring … any rate, Guard Ring locates around the peripheral position.

Kai: In Fig2., what caused the left side of the signal increased more sharply compared with the righthand side? it seems more clear on plot (b), and there’s a small tail on the right side. Ryuta: Maybe, the total amplitude (by the multiply layer) as well as the enhanced E-field.

Finally,Gushan introduced first measurement of𝝌𝒄𝑱 → 𝜮+𝒑𝑲^𝑺𝟎+𝒄. 𝒄(J=0, 1, 2) decays. The main contents are data sets, event selection, background analysis, systematic uncertainties and summary.