Time Resolution of an Irradiated 3D Silicon Pixel Detector

Abstract

We report on the measurements of time resolution for double-sided 3D pixel sensors with a single cell of 50 μm × 50 μm and thickness of 285 μm, fabricated at IMB-CNM and irradiated with reactor neutrons from 8 ×1014 1MeV neq/cm2 to 1.0 ×1016 1MeV neq/cm2. The time resolution measurements were conducted using a radioactive source at a temperature of −20 and 20 °C in a bias voltage range of 50–250 V. The reference time was provided by a low gain avalanche detector produced by Hamamatsu. The results are compared to measurements conducted prior to irradiation where a temporal resolution of about 50 ps was measured. These are the first ever timing measurements on an irradiated 3D sensor and which serve as a basis for understanding their performance and to explore the possibility of performing 4D tracking in high radiation environments, such as the innermost tracking layers of future high energy physics experiments.

Silicon detectors for precision track timing

“…A conventional Column-3D sensors (50×50 𝜇m 2 ) have also demonstrated good time resolution up to equivalent fluence of 10 16 cm −2 (see Fig. 8)a [36]. The contributions to the time resolution measured with discrete electronics show 𝜎 𝑤 𝑓 as dominant contribution, which is at the comparable cell size worse than for the Trench-3D.…”

“…From their proposal 3D detectors were envisaged to offer good timing properties [34], but have only recently been investigated for the ultimate time performance [35][36][37]. As the drift path is separated from the thickness (signal), fast rise-time and good enough 𝑆/𝑁 required for small jitter can be achieved without gain.…”

Measurements of time resolution of the RD50-MPW2 DMAPS prototype using TCT and 90Sr

“…For example, during the Phase-II upgrade of the ATLAS experiment [4], a new High Granularity Timing Detector will be installed to provide track time information with a resolution below 50 ps [5], enhancing the performance of the planned new tracking system. Various studies of time resolution dealing with different silicon detector technologies have already been carried out, see for example [6,7] and [8].…”

A Modified 3D-Trench Pixel Detector: Proof of Concept by TCAD Simulations

“…The peculiar geometry of 3D detectors make them intrinsically fast devices [6], but the first study about their timing properties was only published in 2011 [7], reporting timing resolution from ~30 ps to ~180 ps in non-optimized test structures. Recently, a small-pitch (50 μm × 50 μm) 3D single-pixel test structure fabricated at CNM (Barcelona, Spain) was tested using a fast discrete readout channel, showing a timing resolution of ~30 ps at 150 V bias and −20 °C [8] and still lower than 50 ps after irradiation up to 1 × 10 16 n eq /cm 2 [9]. These remarkable results are however limited by the spatial non-uniformity of the electric and weighting fields within a pixel, which are typical of 3D sensors [6,7].…”