Pixelated LGADs have been established as the baseline technology for timing detectors for the High Granularity Timing Detector (HGTD) and the Endcap Timing Layer (ETL) of the ATLAS and CMS experiments, respectively. The drawback of segmenting an LGAD is the non-gain area present between pixels and the consequent reduction in the fill factor. To overcome this issue, the inverse LGAD (iLGAD) technology has been proposed by IMB-CNM to enhance the fill factor and provide excellent tracking capabilities. In this work, we explore the use of iLGAD sensors for surface damage irradiation by developing a new generation of iLGADs, the periphery of which is optimized to improve the performance of irradiated sensors. The fabricated iLGAD sensors exhibit good electrical performances before and after X-ray irradiation.

The high-luminosity upgrade of the ATLAS and CMS experiments includes dedicated sub-detectors to perform the time-stamping of minimum ionizing particles (MIPs). These detectors will be exposed up to fluences in the range of 1.5–2.5×1015neq/cm2 and require a time resolution per detecting layer of 30 ps, for non-irradiated sensors, to 50–70 ps (depending on the exposed fluences) for sensors at the end of their lifetime. To cope with these requirements, the low-gain avalanche diode (LGAD) has been chosen as the baseline detection technology. In this article, an in-depth radiation tolerance study on LGADs manufactured at IMB-CNM using a so-called shallow junction is presented. Proton irradiation at CERN-PS up to fluences of 3×1015neq/cm2 and neutron irradiation at JSI-Ljubljana up to 2.5×1015neq/cm2 were performed. Two different active thicknesses were studied: 35μm and 50μm. Gain degradation, operation stability, and timing performance were evaluated.

Silicon sensors are the go-to technology for high-precision sensors in particle physics. But only recently low-noise silicon sensors with internal amplification became available. The so-called Low Gain Avalanche Detector (LGAD) sensors have been developed for applications in High Energy Physics, but lack two characteristics needed for the measurement of low-energy protons (<60 keV): a thin entrance window (in the order of tens of nm) and the efficient amplification of signals created near the sensor's surface (in a depth below 1 um). In this paper we present the so-called proton Low Gain Avalanche Detector (pLGAD) sensor concept and some results from characterization of the first prototypes of the sensor. The pLGAD is specifically designed to detect low-energy protons, and other low-penetrating particles. It will have a higher detection efficiency than non-silicon technologies, and promises to be a lot cheaper and easier to operate than competing silicon technologies.

In this contribution, we will present the status of the technological developments at IMB-CNM to fabricate Inverse Low Gain Avalanche Detectors (iLGAD) for pixelated detectors. This iLGAD sensor concept is one of the most promising technologies for enabling the future 4D tracking paradigm that requires both precise position and timing resolution. In the iLGAD concept, based on the LGAD technology, the readout is done at the ohmic contacts, allowing for a continuous unsegmented multiplication junction. This architecture provides a uniform gain over all the active sensor area. This concept was successfully demonstrated in a first generation of 300 μm thick iLGAD sensors. In the second generation, we have fabricated thick iLGAD sensor optimizing the periphery for X-Ray irradiations. Currently, we are developing a third generation based on 50 μm thick pixelated iLGADs optimized for timing detection, with a periphery design able to sustain high electric fields and a simpler single-side manufacturing process.

In this work, we present the pLGAD concept, which is based on the LGAD technology developed at IMB-CNM. We describe the main characteristics of this novel detector suitable for low energy particles detection. Using 2D TCAD numerical simulations we optimize its multiplication region characteristics, the V BD -Gain trade-off and the periphery design. Also, we define a first pLGAD fabrication run to integrate it at IMB-CNM clean room. Moreover, we describe the first n-type LGAD prototype.