This work is a continuation of our preliminary tests on NIRCA - the Near Infrared Readout and Controller ASIC [1]. The primary application for NIRCA is future astronomical science and Earth observation missions where NIRCA will be used with mercury cadmium telluride image sensors (HgCdTe, or MCT) [2], [3]. Recently we have completed the ASIC tests in the cryogenic environment down to 77 K. We have verified that NIRCA provides to the readout integrated circuit (ROIC) regulated power, bias voltages, and fully programmable digital sequences with sample control of the analogue to digital converters (ADC). Both analog and digital output from the ROIC can be acquired and image data is 8b/10b-encoded and delivered via serial interface. The NIRCA also provides temperature measurement, and monitors several analog and digital input channels. The preliminary work confirms that NIRCA is latch-up immune and able to operate down to 77 K. We have tested the performance of the 12-bit ADC with pre-amplifier to have 10.8 equivalent number of bits (ENOB) at 1.4 Msps and maximum sampling speed at 2 Msps. The 1.8-V and 3.3-V output regulators and the 10-bit DACs show good linearity and work as expected. A programmable sequencer is implemented as a micro-controller with a custom instruction set. Here we describe the special operations of the sequencer with regards to the applications and a novel approach to parallel real-time hardware outputs. The test results of the working prototype ASIC show good functionality and performance from room temperature down to 77 K. The versatility of the chip makes the architecture a possible candidate for other research areas, defense or industrial applications that require analog and digital acquisition, voltage regulation, and digital signal generation.

The detector readout for the Radiation-hard Electron Monitor (RADEM) aboard the JUpiter ICy moons Explorer (JUICE) uses a custom-made application-specific integrated circuit (ASIC, model: IDE3466) for the charge signal readout from silicon radiation sensors. RADEM measures the total ionizing dose and dose rate for protons (5 MeV to 250 MeV), electrons (0.3 MeV to 40 MeV) and ions. RADEM has in total three chips of the same design: one chip for the proton and ion detector, one for the electron detector, and one for the directional detector. The ASIC has 36 chargesensitive pre-amplifiers (CSA), 36 counters of 22-bits each, and one analogue output for multiplexing the pulse heights from all channels. The counters count pulses from charged particles in the silicon sensors depending on the charge magnitude and the coincidence trigger pattern from the 36 channels. We have designed the ASIC in 0.35-mu m CMOS process and an ASIC wafer lot has been manufactured at AMS. This article presents the ASIC design specifications and design validation results. The preliminary results from tests with bare chips indicate that the design meets the technical requirements.

SIPHRA is an integrated circuit (IC) for the readout of photon detectors, such as photomultiplier tubes (PMTs), silicon photomultipliers (SiPMs), and multi-pixel photon counters (MPPCs). The IC has 16 input channels and one summing channel. Each channel can be used for pulse height spectroscopy and timing. The summing channel is important for the readout of detector arrays with monolithic scintillators. The programmable shaping time of 200 ns, 400 ns, 800 ns, or 1600 ns allows for pulse-height spectroscopy using scintillators with different light emission properties. The current mode input stage (CMIS) is designed for large negative charge (-16 nC, -8 nC, -4 nC, and -0.4 nC), depending on the programmable attenuation, and it accommodates large capacitive load (several nF) and large leakage current (up to -100 μA from dark counts). Alternatively, the CMIS can be by-passed to allow for positive charge depending on programmable gain (+40 pC, +4 pC, +0.4 pC). The IC contains one 12-bit analog-to-digital converter (ADC) that allows for digitization of the pulseheights from all channels, including the summing channel at a sampling rate of 50 ksps. Every channel output is available for external use and provides either the analog or a digital trigger/timing pulse with fixed width or time-over-threshold. The programmable channel output facilitates many applications, such as external waveform sampling and digitization, pulse height and time spectroscopy, pulse counting, and triggering. The IC operates at 3.3-V supply voltage and dissipates about 15 mW without CMIS and 30 mW with CMIS active. To save power, any channel or function can be powered down. The ASIC has a serial peripheral interface (SPI) for programming its register settings and for slow ADC data readout; faster readout with up to 1 Mbit/s is possible via a serial data transmission line.

In this paper we present initial test results of the Near Infrared Readout and Controller ASIC (NIRCA), designed for large area image sensors under contract from the European Space Agency (ESA) and the Norwegian Space Center. The ASIC is designed to read out image sensors based on mercury cadmium telluride (HgCdTe, or MCT) operating down to 77 K. IDEAS has developed, designed and initiated testing of NIRCA with promising results, showing complete functionality of all ASIC sub-components. The ASIC generates programmable digital signals to clock out the contents of an image array and to amplify, digitize and transfer the resulting pixel charge. The digital signals can be programmed into the ASIC during run-time and allows for windowing and custom readout schemes. The clocked out voltages are amplified by programmable gain amplifiers and digitized by 12-bit, 3-Msps successive approximation register (SAR) analogue-to-digital converters (ADC). Digitized data is encoded using 8-bit to 10-bit encoding and transferred over LVDS to the readout system. The ASIC will give European researchers access to high spectral sensitivity, very low noise and radiation hardened readout electronics for astronomy and Earth observation missions operating at 77 K and room temperature. The versatility of the chip makes the architecture a possible candidate for other research areas, or defense or industrial applications that require analog and digital acquisition, voltage regulation, and digital signal generation.

The article describes the near infrared readout and controller ASIC (NIRCA) developed by Integrated Detector Electronics AS (IDEAS). The project aims at future astronomical science and Earth observation missions, where the ASIC will be used with image sensors based on mercury cadmium telluride (HgCdTe, or MCT). NIRCA is designed to operate from cryogenic temperatures (77 K) to higher than room temperature (328 K) and in a high radiation environment (LET > 60 MeVcm(2)/mg). The ASIC connects to the readout integrated circuit (ROIC) and delivers fully digitized data via serial digital output. The ASIC contains an analogue front-end (AFE) with 4 analogue-to-digital converters (ADCs) and programmable gain amplifiers with offset adjustment. The ADCs have a differential input swing of +/-2 V, 12-bit resolution, and a maximum sample rate of 3 MSps. The ASIC contains a programmable sequencer (microcontroller) to generate up to 40 digital signals for the ROIC and to control the analogue front-end and DACs on the chip. The ASIC has two power supply voltage regulators that provide the ROIC with 1.8 V and 3.3 V, and programmable 10-bit DACs to generate 16 independent reference and bias voltages from 0.3 V to 3 V. In addition NIRCA allows one to read 8 external digital signals, and monitor external and internal analogue signals including on-chip temperature. NIRCA can be programmed and controlled via SPI interface for all internal functions and allows data forwarding from and to the ROIC SPI interface.

The IDE 4281 is an application specific integrated circuit (ASIC) that has been designed for the readout of CdTe/CZT radiation detectors in space. The chip can be used for single photon spectroscopy of x-rays and γ -rays with energy between 3.5 keV and 140 keV and rate up to 100 kcps per chip. The chip contains 12 low-noise pre-amplifiers (110 e equivalent noise charge, ENC), each followed by a pulse shaper (6 programmable peaking times from 0.75 μs to 4 μs) and a level comparator for triggering. The amplifiers are optimized for negative polarity input charge up to -5 fC. When a charge from the detector exceeds one of the adjustable thresholds, the chip delivers a data packet containing the address of the triggering channel and it delivers an analog signal proportional to the energy deposited by the photon in the detector. The chip requires positive and negative voltage supplies (+1.5 V and -2 V) and one reference bias current to generate its internal bias currents. The total power is 19 mW in idle state and 25 mW maximum. The chip has a 113-bit shift register, programmable via a serial interface, which allows one to set various functions, to program digital-to-analogue converters (DACs), and to tune parameters. Each channel has an optional compensation for detector leakage currents. All amplifier inputs are protected by diodes against over-voltage and electrostatic discharge (ESD). The engineering model (EM) and flight model (FM) ASICs have been designed and manufactured. The article describes the results obtained with the EM ASIC and the design of the FM ASIC.

The IDE 3465 is an application specific integrated circuit (ASIC) that has been designed for the readout of silicon detectors for charged particles. The chip has 20 inputs of charge sensitive pre-amplifiers (CSA), a total of 37 digital logic trigger outputs, and one analogue multiplexer output for pulse heights. Out of the 20 channels, 16 have a high gain with saturation at 2.6 pC, and 4 have a low gain with saturation at 26 pC. The chip is optimized for positive input charges, i.e., it is suitable for the readout and triggering of the charge from the p-side of silicon sensors. In the high-gain channels, the charge sensitive pre-amplifier is connected to one slow shaper of 1-μs shaping time and two fast shapers of 250-ns shaping time, while the low-gain channels have only one slow shaper and one fast shaper of 1-μs and 250-ns shaping time. Each fast shaper output is connected to a comparator, which triggers when the pulse shape exceeds the reference level that can be programmed by 8-bit DACs. The two fast shapers and comparators of the high-gain channels are used for charges in the range from 1 fC to 100 fC and from 100 fC to 2.6 pC, respectively. The fast shapers and comparators of the low-gain channels are designed for charges in the range from 1 pC to 26 pC. Each comparator feeds a mono-stable output, which can be connected directly to an FPGA. The chip requires negative and positive voltage supplies (-2 V, +1.5 V and +3.3 V) and one reference bias current to generate its internal biases. The total power consumption is less than 65 mW, depending on the input event rate and options enabled. The chip has a 356-bit register, programmable via serial interface, which allows one to set various functions, to program digital-to-analogue converters (DACs), and to tune parameters. All amplifier inputs are protected by diodes against over-voltage and electro-static discharge (ESD). The chip is SEU/SEL radiation hardened by design and manufacture.

We have developed an application specific integrated circuit (ASIC) suitable for the readout of up to 64 silicon photomultipliers (SiPM) or multi-pixel photon counters (MPPCs). The ASIC can be used with SiPMs/MPPCs and scintillators for energy spectroscopy and timing of ionizing radiation and provides important functionality for SiPMs: The preamplifier input potential can be programmed to adjust the bias voltage for the SiPMs connected to the input. The input charge range is relatively large (−20 pC to 55 pC) and the input noise can be as low as 1 fC. The ASIC triggers, if one of the input signals exceeds the threshold voltage, and the signal amplitude can be sampled. For all readout channels the ASIC delivers the signal amplitude, i.e., photon energy, and the time between the trigger and the sample. The ASIC has a programmable register to configure digital-to-analog converters for the preamplifier input potentials, the trigger thresholds, the internal bias setting and other functionality. Many ASICs can be combined for the readout of multiple arrays of SiPMs/MPPCs. The preamplifier input is designed for capacitive load of up to 300 pF and a dark current of up to 10 μA. We have produced and tested the ASIC connected to MPPCs and LYSO scintillators. The article describes the functionality of the ASIC and shows energy spectra measured with radioactive sources.

We have developed and constructed an MR-compatible single photon emission computed tomography (SPECT) system for small animal molecular imaging applications. The system consists of identical radiation imaging modules and a multi-pinhole collimator sleeve. The modular design results in a very compact system which allows for easy insertion into state-of-the-art small animal MRI systems. This development leads to a multi-modality system that allows one to accurately coregister SPECT and MR images in space and time. The MR-compatible SPECT unit has a barrel shape with 119-mm outer diameter designed to fit into an MRI system with a 120-mm diameter inner bore. The inner diameter of the SPECT unit is 35 mm which is large enough to fit a mouse, and provides a 30-mm diameter imaging field of view (FOV). The system does not require active cooling due to its low-power dissipation. The radiation sensor performance is not affected by the presence of the magnetic field from the MRI system. The results are very promising for applications of the SPECT/MR system to small animal imaging.