Testbeam results of the Picosecond Avalanche Detector proof-of-concept prototype

The proof-of-concept prototype of the Picosecond Avalanche Detector, a multi-PN junction monolithic silicon detector with continuous gain layer deep in the sensor depleted region, was tested with a beam of 180 GeV pions at the CERN SPS. The prototype features low noise and fast SiGe BiCMOS frontend electronics and hexagonal pixels with 100 μm pitch. At a sensor bias voltage of 125 V, the detector provides full efficiency and average time resolution of 30, 25 and 17 ps in the overall pixel area for a power consumption of 0.4, 0.9 and 2.7 W/cm2, respectively. In this first prototype the time resolution depends significantly on the distance from the center of the pixel, varying at the highest power consumption measured between 13 ps at the center of the pixel and 25 ps in the inter-pixel region

Picosecond Avalanche Detector — working principle and gain measurement with a proof-of-concept prototype

The Picosecond Avalanche Detector is a multi-junction silicon pixel detector based on a (NP)drift(NP)gain structure, devised to enable charged-particle tracking with high spatial resolution and picosecond time-stamp capability. It uses a continuous junction deep inside the sensor volume to amplify the primary charge produced by ionizing radiation in a thin absorption layer. The signal is then induced by the secondary charges moving inside a thicker drift region. A proof-of-concept monolithic prototype, consisting of a matrix of hexagonal pixels with 100 μm pitch, has been produced using the 130 nm SiGe BiCMOS process by IHP microelectronics. Measurements on probe station and with a 55Fe X-ray source show that the prototype is functional and displays avalanche gain up to a maximum electron gain of 23. A study of the avalanche characteristics, corroborated by TCAD simulations, indicates that space-charge effects due to the large primary charge produced by the conversion of X-rays from the ^55Fe source limits the effective gain

Testbeam Results of the Picosecond Avalanche Detector Proof-Of-Concept Prototype

The proof-of-concept prototype of the Picosecond Avalanche Detector, a multi-PN junction monolithic silicon detector with continuous gain layer deep in the sensor depleted region, was tested with a beam of 180 GeV pions at the CERN SPS. The prototype features low noise and fast SiGe BiCMOS frontend electronics and hexagonal pixels with 100 {\mu}m pitch. At a sensor bias voltage of 125 V, the detector provides full efficiency and average time resolution of 30, 25 and 17 ps in the overall pixel area for a power consumption of 0.4, 0.9 and 2.7 W/cm^2, respectively. In this first prototype the time resolution depends significantly on the distance from the center of the pixel, varying at the highest power consumption measured between 13 ps at the center of the pixel and 25 ps in the inter-pixel region

Investigation of high resistivity p-type FZ silicon diodes after 60Co γ-irradiation

In this work, the effects of $^\text{60}$Co $\gamma$-ray irradiation on high resistivity $p$-type diodes have been investigated. The diodes were exposed to dose values of 0.1, 0.2, 1, and \SI2{\mega Gy}. Both macroscopic ($I$--$V$, $C$--$V$) and microscopic (Thermally Stimulated Current~(TSC)) measurements were conducted to characterize the radiation-induced changes. The investigated diodes were manufactured on high resistivity $p$-type Float Zone (FZ) silicon and were further classified into two types based on the isolation technique between the pad and guard ring: $p$-stop and $p$-spray. After irradiation, the macroscopic results of current-voltage and capacitance-voltage measurements were obtained and compared with existing literature data. Additionally, the microscopic measurements focused on the development of the concentration of different radiation-induced defects, including the boron interstitial and oxygen interstitial (B$_\text{i}$O$_\text{i}$) complex, the carbon interstitial and oxygen interstitial C$_\text{i}$O$_\text{i}$ defect, the H40K, and the so-called I$_\text{P}^*$. To investigate the thermal stability of induced defects in the bulk, isochronal annealing studies were performed in the temperature range of \SI{80}{\celsius} to \SI{300}{\celsius}. These annealing processes were carried out on diodes irradiated with doses of 1 and \SI2{\mega Gy} and the corresponding TSC spectra were analysed. Furthermore, in order to investigate the unexpected results observed in the $C$-$V$ measurements after irradiation with high dose values, the surface conductance between the pad and guard ring was measured as a function of both dose and annealing temperature

The Boron–Oxygen (BᵢOᵢ) Defect Complex Induced by Irradiation With 23 GeV Protons in p-Type Epitaxial Silicon Diodes

In this work, the thermally stimulated current (TSC) technique has been used to investigate the properties of the radiation-induced interstitial boron and interstitial oxygen defect complex by 23-GeV ( $E_{\text {kin}}$ ) protons, including activation energy, defect concentration, as well as the annealing behavior. At first isothermal annealing (at 80 °C for 0–180 min) followed by isochronal annealing (for 15 min between 100 °C and 190 °C in steps of 10 °C), studies had been performed in order to get information about the thermal stability of the interstitial boron and interstitial oxygen defect in 50- $\Omega$ cm material after irradiation with 23-GeV protons to a fluence of $6.91\times 10^{13}\,\,{\text {p/cm}^{2}}$ . The results are presented and discussed. Furthermore, the extracted data from TSC measurements are compared with the macroscopic properties derived from current–voltage and capacitance–voltage characteristics. In addition, the introduction rate of interstitial boron and interstitial oxygen defect as a function of the initial doping concentration was determined by exposing diodes with different resistivities (10, 50, 250, and 2 $\text{k}\Omega$ cm) to 23-GeV protons. These results are compared with data from TSC and deep-level transient spectroscopy measurements achieved by the team of the CERN-RD50 “Acceptor removal project.

Deep diffused Avalanche photodiodes for charged particles timing

The upgrades of ATLAS and CMS for the High Luminosity LHC (HL-LHC) highlighted physics objects timing as a tool to resolve primary interactions within a bunch crossing. Since the expected pile-up is around 200, with an r.m.s. time spread of 180ps, a time resolution of about 30ps is needed. The timing detectors will experience a 1-MeV neutron equivalent fluence of about Φ eq=10 14 and 10 15cm −2 for the barrel and end-cap regions, respectively. In this contribution, deep diffused Avalanche Photo Diodes (APDs) produced by Radiation Monitoring Devices are examined as candidate timing detectors for HL-LHC applications. To improve the detector's timing performance, the APDs are used to directly detect the traversing particles, without a radiator medium where light is produced. Devices with an active area of 8 × 8mm 2 were characterized in beam tests. The timing performance and signal properties were measured as a function of position on the detector using a beam telescope and a microchannel plate photomultiplier (MCP-PMT). Devices with an active area of 2 × 2mm 2 were used to determine the effects of radiation damage and characterized using a ps pulsed laser. These detectors were irradiated with neutrons up to Φ eq=10 15cm −2

Efficiency and time resolution of monolithic silicon pixel detectors in SiGe BiCMOS technology

A monolithic silicon pixel detector prototype has been produced in the SiGe BiCMOS SG13G2 130 nm node technology by IHP. The ASIC contains a matrix of hexagonal pixels with pitch of approximately 100 μm. Three analog pixels were calibrated in laboratory with radioactive sources and tested in a 180 GeV/c pion beamline at the CERN SPS. A detection efficiency of (99.9$_{-0.2}$ $^{+0.1}$)% was measured together with a time resolution of (36.4 ± 0.8) ps at the highest preamplifier bias current working point of 150 μA and at a sensor bias voltage of 160 V. The ASIC was also characterized at lower bias voltage and preamplifier current.A monolithic silicon pixel detector prototype has been produced in the SiGe BiCMOS SG13G2 130 nm node technology by IHP. The ASIC contains a matrix of hexagonal pixels with pitch of approximately 100 $\mu$m. Three analog pixels were calibrated in laboratory with radioactive sources and tested in a 180 GeV/c pion beamline at the CERN SPS. A detection efficiency of $\left(99.9^{+0.1}_{-0.2}\right)$% was measured together with a time resolution of $(36.4 \pm 0.8)$ps at the highest preamplifier bias current working point of 150 $\mu$A and at a sensor bias voltage of 160 V. The ASIC was also characterized at lower bias voltage and preamplifier current

Gain measurements of the first proof-of-concept PicoAD prototype with a 55Fe X-ray radioactive source

The Picosecond Avalanche Detector is a multi-junction silicon pixel detector devised to enable charged-particle tracking with high spatial resolution and picosecond time-stamping capability. A proof-of-concept prototype of the PicoAD sensor has been produced by IHP microelectronics. Measurements with a 55Fe X-ray radioactive source show that the prototype is functional with an avalanche gain up to a maximum electron gain of 23