Speaker
Marcela Mikestikova
(Acad. of Sciences of the Czech Rep. (CZ))
Description
on behalf of the ATLAS ITk Strip Sensor Collaboration
A radiation hard *n*-in-*p* micro-strip sensor for the use in the Upgrade of the strip tracker of the ATLAS experiment at the High Luminosity Large Hadron Collider (HL-LHC) has been developed by the “ATLAS ITk Strip Sensor collaboration” and produced by Hamamatsu Photonics.
Surface properties of different types of end-cap and barrel miniature sensors of the latest sensor design ATLAS12 have been studied before and after proton and gamma irradiation. The tested barrel sensors vary in “punch-through protection” (PTP) structure; while the end-cap sensors having stereo-strips in fan geometry differ also in strip pitch, in stray strip ganging and in fan geometry. Sensors have been irradiated with cyclotron protons at University of Birmingham (UK), at Karlsruhe Inst. Tech. (Germany) and at CYRIC, Tohoku University (Japan) up to fluence of 1E16n$_e$$_q$/cm$^2$ and by gamma in BNL (USA) up to dose of 100kGy.
The main goal of presented study was to characterize the leakage current for micro-discharge breakdown voltage estimation, the inter-strip resistance and capacitance, the bias resistance and the effectiveness of PTP structure as a function of bias voltage and fluence. It has been verified that the ATLAS12 sensors have high breakdown voltage well above the operational voltage which implies that different geometries of sensors do not influence their stability. The interstrip isolation is a strong function of irradiation fluence, however the sensor performance is acceptable in the expected range for HL-LHC. New gated PTP structure exhibits low PTP onset voltage and sharp cut-off of effective resistance even at the highest tested radiation fluence. The inter-strip capacitance complies with the technical specification required before irradiation and no radiation-induced degradation was observed.
A summary of ATLAS12 sensors test will be presented including a comparison of results from different irradiation sites. The measured characteristics will be compared with ATLAS07 sensor design.
Author
Marcela Mikestikova
(Acad. of Sciences of the Czech Rep. (CZ))
