Recently I have been working on the measurement of the inter-pixel distance of novel Trench Isolated LGAD (TI-LGAD) detectors. I presented my results in the 39th RD50 Workshop in Valencia.
In this link you can find my slides, which I also embed here:
This post is to provide a (very) brief summary of my work.
First of all, what is a TI-LGAD? TI-LGAD is a novel technology to extend the application of LGAD detectors to high granularity applications, this means to create a pixelated array of LGADs with a pixel size between 25 and 100 µm and with a reasonable fill factor > 80 %. The TI-LGAD technology “competes” against the AC-LGAD technology to achieve high temporal and spacial resolution in the same device. In the TI-LGAD technology each pixel is isolated from its surrounding pixels by etching physical trenches. Below there is a cartoon illustrating this.
At UZH we received a fraction of the RD50 production of TI-LGADs, which was produced by FBK. Measurements were done using the TCT setup that we have at UZH. My results are summarized in the plot below:
In this plot I am showing the Inter-Pixel Distance (IPD) for each of the different design patterns we received at UZH, this is different combinations of trench depth, number of trenches, contact type and pixel border. As can be seen there are some devices which show practically zero IPD at the operating voltage of 200 V.
The TI-LGADs were shipped yesterday to Jožef Stefan Institute – RIC to be irradiated with neutrons and hopefully I can re-measure the IPD and observe its degradation.