Sep 12 – 17, 2021
University of Birmingham
Europe/London timezone

Characterization of a large LGAD sensor for proton counting in particle therapy

Sep 14, 2021, 3:20 PM
15m
Teaching and Learning Building (University of Birmingham)

Teaching and Learning Building

University of Birmingham

Edgbaston Campus University of Birmingham B15 2TT UK

Speaker

Oscar Ariel Marti Villarreal (INFN - National Institute for Nuclear Physics)

Description

Purpose:
Based on LGAD technology, a fast proton counter prototype is being developed for the online monitoring of the fluence rate of therapeutic proton beams. The laboratory characterization of dedicated LGAD sensors segmented in strips covering an area of 2.7x2.7 cm^2 is reported.
Methods:
The LGAD sensor is segmented into 146 strips (160 um width, 26260 um length, 180 um pitch, 2 strips without gain, 144 strips with gain, and a nominal inter-strip distance of 66 um). A dedicated production at Fondazione Bruno Keeler (FBK, Trento, Italy) in 2020 consisted of 14 wafers with two different active thicknesses (55 um Si-Si wafers, 45 um for the Epi ones), with shallow gain implants, two p-gain doses, boron- low diffusion, co-implanted with a dose of carbon to improve the radiation resistance. Laboratory characterization of this production was performed at the University of Torino and at FBK, using a probe station, connected with a power devices analyzer for static DC electrical test, and the TCT to study dynamic properties of our sensors.
Results:
A global yield ratio between working strips over the total number of strips measured in the entire production of 89.4% and a mean breakdown voltage for good sensors (sensors without bad strips) measured on the backplane of about 212 V were found. The average full depletion voltage obtained was 22.12-23.47 V and 34.98 V for Si-Si and Epi wafers, respectively. Furthermore, the ratio between the 90/10 percentile for the leakage current at 160 V was lower than 1.6 for all the cases. The inter-strip distance measured was 80.8 um, 22% larger than the nominal no-gain distance, as previously observed by other groups.
Conclusion: 
The laboratory characterization showed good results and prepared the groundwork for the selection of the best set of sensors to be tested on clinical proton beams.

email martivil@to.infn.it
Institute Universita e INFN Torino (IT)
Title Dr
Nationality Cuban
Your name Oscar Ariel Marti Villarreal

Primary authors

Oscar Ariel Marti Villarreal (INFN - National Institute for Nuclear Physics) Mr Giuseppe Peroglio Carus (UNITO) Dr Mohammed Abujami (UNITO) Matteo Centis Vignali (FBK) Marco Ferrero (Universita e INFN Torino (IT)) Mr Cosimo Galeone (UNITO) Simona Giordanengo (Istituto Nazionale di Fisica Nucleare) Omar Hammad Ali (INFN - National Institute for Nuclear Physics) Dr Felix Mas Milian (UNITO) Anna Vignati (INFN - National Institute for Nuclear Physics) Roberto Cirio (Universita e INFN Torino (IT)) Vincenzo Monaco (Universita e INFN Torino (IT)) Roberto Sacchi (University of Torino)

Presentation materials