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Study of Interpad-gap of FBK (UFSD3) and HPK 3.1 Type sensors with Transient Current Technique

Dec 14, 2019, 3:23 PM
POSTER - Sun: B1F-Meeting room#3, B2F-RAN1/2; Mon-Wed: B1F Meeting rooms #5-6 (International Conference Center Hiroshima)

POSTER - Sun: B1F-Meeting room#3, B2F-RAN1/2; Mon-Wed: B1F Meeting rooms #5-6

International Conference Center Hiroshima

Peace Memorial Park, Hiroshima-shi
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Shudhashil Bharthuar (University of Helsinki)


The Phase-II upgrade of LHC to HL-LHC by 2026 allows an increase in the operational luminosity value by a factor of 5-7 that will result in delivering 3000~fb$^{-1}$ or more integrated luminosity. This amount of data will not just allow an increase in the precision of the Standard Model(SM) measurements but also widen the horizon for Beyond Standard Model(BSM) searches. To achieve high luminosity, a number of interactions per bunch crossings (pileup) will increase up to a value of 140-200. To cope with high pileup rates, precision timing detector (MTD) that will measure minimum ionizing particles (MIPs) with a time resolution of ~30-40 ps and hermetic coverage up to a pseudo-rapidity of $|\eta|$ = 3 is proposed by the CMS experiment. An endcap part (1.6~$<|\eta|<$~3) of MIP timing detector (ETL) will be based on low-gain avalanche detector (LGAD) technology.
The third production of Ultra Fast Silicon Detectors (UFSD3) from Fondazione Bruno Kessler (FBK) and Low Gain Avalanche Detectors (LGADs) from Hamamatsu Photonics K.K. (HPK) include 2x2 sensors with different structural strategies, in particular, different values of narrower inactive region widths between the pads. These sensors have been designed to study specific features required for the ETL. A comparative study on the dependence of breakdown voltage with the inter-pad gap width for both sensor types has been carried out. Results of measured inter-pad gap widths and spatial mappings within their non-active regions using MIPs (IR light) from the Scanning-Transient Current Technique (Scanning-TCT) set-up will be shown. A fill-factor, which is the ratio of the area within the active region (Gain region) to the area of the total scanning region has been studied. Results on how fill-factor varies depending on temperature (from 25$^{\circ}$C to -25$^{\circ}$C) and proton fluence on irradiation will also be shown.

Submission declaration Original and unpublished

Primary author

Shudhashil Bharthuar (University of Helsinki)


Jennifer Ott (Helsinki Institute of Physics (FI)) Jens Erik Brucken (Helsinki Institute of Physics (FI)) Vladyslav Litichevskyi (Helsinki Institute of Physics (FI)) Tiina Sirea Naaranoja (Helsinki Institute of Physics (FI)) Laura Martikainen (Helsinki Institute of Physics (FI)) Akiko Gädda (Helsiki Institute of Physics) Stefanie Kirschenmann (Helsinki Institute of Physics (FI)) Panja Luukka (Helsinki Institute of Physics (FI))

Presentation materials