Konrad Briggl

STiC ? a mixed mode silicon photomultiplier readout ASIC for time-of-flight applications

STiC is an application specific integrated circuit (ASIC) for the readout of silicon photomultipliers. The chip has been designed to provide a very high timing resolution for time-of-flight applications in medical imaging and particle physics. It is dedicated in particular to the EndoToFPET-US project, which is developing an endoscopic PET detector combined with ultrasound imaging for early pancreas and prostate cancer detection. This PET system aims to provide a spatial resolution of 1 mm and a time-of-flight resolution of 200 ps FWHM. The analog frontend of STiC can use either a differential or single ended connection to the SiPM. The time and energy information of the detector signal is encoded into two time stamps. A special linearized time-over-threshold method is used to obtain a linear relation between the signal charge and the measured signal width, improving the energy resolution. The trigger signals are digitized by an integrated TDC module with a resolution of less than 20 ps. The TDC data is stored in an internal memory and transfered over a 160 MBit/s serial link using 8/10 bit encoding. First coincidence measurements using a 3.1 × 3.1 × 15 mm3 LYSO crystal and a S10362-33-50 Hamamtsu MPPC show a coincidence time resolution of less than 285 ps. We present details on the chip design as well as first characterization measurements.

STiC - A mixed mode chip for SiPM ToF applications

STiC is a mixed mode 16-channel ASIC chip in UMC 0.18 /Lm CMOS technology aiming at Silicon Photomultiplier (SiPM) readout with optimal timing resolution. It is designed for ToF measurements in HEP and medical imaging applications and dedicated in particular to the ENDOToFPET·US project, which aims at providing a powerful endoscopic Time· of-Flight PET system for early prostate and pancreas cancer diagnostics. The goal of this endoscopic system is to provide a spatial resolution of the order of 1 mm and a Time-of-Flight resolution of 200 ps FWHM. The STiC chip has a differential structure. However, SiPMs can be connected either differentially or single-endedly. The timing and charge information of the input signal - both required for a high-resolution ToFPET system - are encrypted into two time stamps and processed later by an embedded TDC module with a timing resolution of better than 20 ps. The digitized data are stored first on an on-chip SRAM block and then transferred via a 160 MBit LVDS serial link using 8/10-bit encoding. The simulated single pixel timing jitter is less than 15 ps for Hamamatsu SI0362-11-50 MPPCs. A special linearization method has been used to obtain a linear charge response in a very wide range. The total power consumption is about 20 m W per channel. Design details as well as first measurement results will be presented.

STiC2 - characterization results of a SiPM readout ASIC for time-of-flight applications

STiC is a mixed-mode readout ASIC for silicon-photomultipliers (SiPM) developed in the framework of the EndoToFPET-US project. The chip has been designed in the UMC 0.18 μm technology and aims to provide an optimal timing resolution to Time-of-Flight measurements in medical imaging and particle physics applications. The differential design of the analog input stage rejects noise from the large integrated digital part as well as external sources. The chip allows either a differential or a single-ended readout of the sensors. The time and charge information of the input signal is converted into two time stamps which are digitized by an integrated TDC module with a time binning of 50 ps. A special linearized Time-over-Threshold method has been implemented to provide a linear response to the signal charge in a wide range. The digitized event information is stored in a 64-word FIFO memory and transmitted every 6.4 μs to an external DAQ system using a 160 MBit=s LVDS serial link with 8/10-bit encoding. Characterization measurements show a trigger jitter of σ <; 30 ps for input signals larger than 3 pC injected over a 33 pF capacitor. A measurement using 3.1 × 3.1 × 15mm3 LYSO crystals and Hamamatsu MPPC (S10362-33-50C) sensors to detect coincidence photons from positron annihilations shows an energy resolution of ~ 12% for the 511 keV peak and a coincidence time resolution of 220 ps FWHM. We present details of the ASIC design as well as characterization measurements.

A dedicated readout ASIC for Time-of-Flight Positron Emission Tomography using Silicon Photomultiplier (SiPM)

STiC is a mixed-mode Application Specific Integrated Circuit (ASIC) for Silicon Photomultiplier (SiPM) readout with very high timing resolution. It is designed for the Time-of-Flight (ToF) measurement in Positron Emission Tomography (PET) and in high energy physics experiments. STiC is dedicated particularly to the EndoTOFPET-US project, which is developing and building a multi-modal instrument combing ToFPET and ultrasound endoscopy for the development of new biomarkers for pancreas and prostate oncology. A 64-channel prototype (STiC v3) has been developed and produced in 0.18μm UMC CMOS technology. A fully differential analog front-end has been developed to suppress the common-mode noise from both the on-chip digital part and the outer sources, while it allows for both differential and single-ended readout connection schemes with SiPM. A digital-to-analog converter on the input stage tunes the SiPM bias voltage with a range of ~ 900 mV, providing the possibility to compensate the variation on the breakdown voltage of the connected SiPMs. A linearized time-over-threshold method has been implemented to provide better energy resolution than the conventional ToT method. The time and energy information are converted into two time stamps, which are digitized by a build-in TDC with time binning of 50.2 ps. A dedicated digital part has been developed for chip configuration with a Serial Peripheral Interface and for data transmission to an external Data Acquisition System using a 160 MBit/s LVDS serial link with 8/10-bit encoding. Measurements have shown a time jitter <; 20 ps on the analog front-end and a time jitter of ~ 37 ps on the TDC and digital part. A Coincidence Time Resolution of ~ 214 ps FWHM has been obtained by STiC v3 with 3.1 × 3.1 × 15 mm2 LYSO:Ce crystals and Hamamatsu MPPCs (S12643-050CN(x)). Here we present the details of the ASIC design, measurement results as well as the 128-channel front-end module for EndoTOFPET-US project.

MuTRiG: a mixed signal Silicon Photomultiplier readout ASIC with high timing resolution and gigabit data link

MuTRiG is a mixed signal Silicon Photomultiplier readout ASIC designed in UMC 180 nm CMOS technology for precise timing and high event rate applications in high energy physics experiments and medical imaging. It is dedicated to the readout of the scintillating fiber detector and the scintillating tile detector of the Mu3e experiment. The MuTRiG chip extends the excellent timing performance of the STiCv3 chip with a fast digital readout for high rate applications. The high timing performance of the fully differential SiPM readout channels and 50 ps time binning TDCs are complemented by an upgraded digital readout logic and a 1.28 Gbps LVDS serial data link. The design of the chip and the characterization results of the analog front-end, TDC and the LVDS data link are presented.

KLauS: an ASIC for silicon photomultiplier readout and its application in a setup for production testing of scintillating tiles

KLauS is an ASIC produced in the AMS 0.35 μm SiGe process to read out the charge signals from silicon photomultipliers. Developed as an analog front-end for future calorimeters with high granularity as pursued by the AHCAL concept in the CALICE collaboration, the ASIC is designed to measure the charge signal of the sensors in a large dynamic range and with low electronic noise contributions. In order to tune the operation voltage of each sensor individually, an 8-bit DAC to tune the voltage at the input terminal within a range of 2V is implemented. Using an integrated fast comparator with low jitter, the time information can be measured with sub-nanosecond resolution. The low power consumption of the ASIC can be further decreased using power gating techniques. Future versions of KLauS are under development and will incorporate an ADC with a resolution of up to 12-bits and blocks for digital data transmission. The chip is used in a setup for mass testing and characterization of scintillator tiles for the AHCAL test beam program.

Characterization Measurement Results of MuTRiG - A Silicon Photomultiplier Readout ASIC with High Timing Precision and High Event Rate Capability

The MuTRiG chip, which is dedicated to the Mu3e experiment, is a 32 channels mixed-signal Silicon Photomultiplier readout ASIC with high timing precision and high event rate capability designed and fabricated in UMC 180nm CMOS technology. It combines the excellent timing performance of the fully differential analog front-ends and the 50ps time binning TDCs with a high event rate capability from a dedicated on-chip digital logic circuit and a gigabit LVDS serial data link. The design of the chip and the results from the characterization measurements will be presented.

KLauS4: A Multi-Channel SiPM Charge Readout ASIC in 0.18µm UMC CMOS Technology

KLauS4 is a 7-channel mixed-mode Silicon-Photomultiplier (SiPM charge readout ASIC dedicated to imaging calorimetry at a possible future linear collider, where one key aspect is the ultra-low power consumption of the readout electronics. The ASIC is designed to read out the SiPM charge information with high precision and over large dynamic range. Each channel consists of a low-noise front-end with two gain branches to deal with a large input signal range, and a 10/12-bit ADC to digitize the charge information; a common digital part for data storage and transmission is also implemented into this chip. Design of the ASIC, characterization measurements and beam-test results will be presented.

KLauS: a low power Silicon Photomultiplier charge readout ASIC in 0.18 UMC CMOS

We present the development of a low power Silicon Photomultiplier charge readout ASIC for an imaging calorimeter at a future linear collider. The analog front-end is designed to achieve sufficient signal-to-noise ratio for single pixel signals using low gain SiPMs, while allowing charge measurements over the full dynamic range of the sensors. The front-end consists of an input stage, two charge measurement branches and a fast comparator. A SAR ADC with a resolution of 10 bit digitizes the pulse height information. An additional pipelined SAR stage allows to increase the quantization resolution to 12 bit for calibration measurements.

Single photon time resolution with silicon photomultipliers using the STiC readout chip

STiC3 is a mixed mode Application Specific Integrated Circuit (ASIC) for high resolution timing readout of Silicon Photomultipliers (SiPMs). It is designed for Time-ofFlight (ToF) applications in medical imaging and High Energy Physics experiments and has been developed in the framework of EndoToFPET-US project. The STiC3 chip uses the UMC 180 nm CMOS technology and has a differential structured front-end to reject common-mode noise. It has 64 channels and each channel consists of an analog front-end, a build-in TDC module and a digital part. In earlier measurements using 3.1×3.1×15 mm3 LYSO crystals and Hamamatsu S10362-33-050C MPPC sensors, a Coincidence Time Resolution (CTR) of ~214 ps FWHM has been obtain; the achieved energy resolution is ~12 % for 511 keV photons. In order to explore the timing performance for small signals a special setup has been established in our laboratory. The setup includes an optical system for automatically focusing a laser beam to a spot size smaller than 3 μm and allows to precisely evaluate the performance of the STiC3 chip as well as to carry out SiPMs characterization studies. A first measurement of the Single Photon Time Resolution (SPTR) using STiC3 is presented in this paper.