In space experiments that study Charged Cosmic Rays (CCRs), a calorimeter combined with a tracker is used to identify the incoming particles. The back-scattered particles from the calorimeter can enter the tracker creating additional hits. The timing measurement for each hit can be utilized to distinguish between the back-scattered and primary hits. Low Gain Avalanche Detector (LGAD) is a promising technology for detecting particles with timing precision O(10) ps being developed for High-Energy Physics (HEP) experiments. With the current LGAD technology, it is difficult to achieve fine segmentation of sensors into channels. The typical size of an LGAD sensor is O(1 mm2) for HEP experiments whereas, silicon strip sensors in space applications have 50-60 cm long channels with 100 μm pitch, resulting in a channel area of about 1 cm2. The goal of this thesis is to evaluate the use of LGADs for timing in space. In view of this, the channel size of LGADs needs to be modified to O(1 cm2) to be utilized in space experiments. The larger channel size poses challenges for the time resolution of the sensors. First, the issues due to signal shape non-uniformity in pads and strips have been investigated, which can affect the timing performance of the sensors. Second, the fill factor problem due to the segmentation of LGADs is studied. The segmentation of LGADs results in the reduced active area of the sensor. Two different LGAD technologies namely RSD and TI-LGADs have been characterized as a possible solution to the segmentation problem. Finally, the work related to the scaling of the channel size of the LGADs from 1 mm2 to 1 cm2 is presented. TCAD simulations have been performed to obtain the process parameters for the gain layer to achieve a gain of 100 thought to improve the time resolution for larger channel areas. A batch of 16 wafers has been produced to study the adaptation of LGADs for space applications. The fabrication parameters have been optimized using TCAD simulations. This thesis contains the first characterization of the batch. This work aims to provide the instruments to advance the understanding of the fundamental properties of the universe and contribute to the development of LGADs technology for astroparticle physics experiments in space.
| Identifer | oai:union.ndltd.org:unitn.it/oai:iris.unitn.it:11572/373147 |
| Date | 30 March 2023 |
| Creators | Bisht, Ashish |
| Contributors | Bisht, Ashish, Zuccon, Paolo |
| Publisher | Università degli studi di Trento, place:Trento |
| Source Sets | Università di Trento |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | firstpage:1, lastpage:126, numberofpages:126 |
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