Resistive AC-Coupled Silicon Detectors: principles of operation and first results from a combined analysis of beam test and laser data

Abstract

This paper presents the principles of operation of Resistive AC-Coupled Silicon Detectors (RSDs) and measurements of the temporal and spatial resolutions using a combined analysis of laser and beam test data. RSDs are a new type of n-in-p silicon sensor based on the Low-Gain Avalanche Diode (LGAD) technology, where the $n^{+}$ implant has been designed to be resistive, and the read-out is obtained via AC-coupling. The truly innovative feature of RSD is that the signal generated by an impinging particle is shared isotropically among multiple read-out pads without the need for floating electrodes or an external magnetic field. Careful tuning of the coupling oxide thickness and the $n^{+}$ doping profile is at the basis of the successful functioning of this device. Several RSD matrices with different pad width-pitch geometries have been extensively tested with a laser setup in the Laboratory for Innovative Silicon Sensors in Torino, while a smaller set of devices have been tested at the Fermilab Test Beam Facility with a 120 GeV/c proton beam. The measured spatial resolution ranges between $2.5\mu m$ for 70-100 pad-pitch geometry and $17\mu m$ with 200-500 matrices, a factor of 10 better than what is achievable in binary read-out ($binsize/\sqrt{12}$). Beam test data show a temporal resolution of $\sim 40ps$ for 200-$\mu m$ pitch devices, in line with the best performances of LGAD sensors at the same gain.

34 pages, 33 figures

References in corpus (3)

• Silicon Sensors for Future Particle Trackers
• Measurements of an AC-LGAD strip sensor with a 120 GeV proton beam
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Cited by in corpus (17)

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• Testbeam Results of the Picosecond Avalanche Detector Proof-Of-Concept Prototype
• The second production of RSD (AC-LGAD) at FBK
• First survey of centimeter-scale AC-LGAD strip sensors with a 120 GeV proton beam
• The performance of large-pitch AC-LGAD with different N+ dose
• First experimental results of the spatial resolution of RSD pad arrays read out with a 16-ch board
• Results for pixel and strip centimeter-scale AC-LGAD sensors with a 120 GeV proton beam
• First Test Results of the Trans-Impedance Amplifier Stage of the Ultra-fast HPSoC ASIC
• Silicon sensors with resistive read-out: Machine Learning techniques for ultimate spatial resolution
• Signal formation and sharing in AC-LGADs using the ALTIROC 0 front-end chip
• Development of a timing chip prototype in 110 nm CMOS technology
• Characterization of BNL and HPK AC-LGAD sensors with a 120 GeV proton beam
• Studying AC-LGAD strip sensors from laser and testbeam measurements
• Design and optimisation of radiation resistant AC- and DC-coupled resistive LGADs