Proof-of-concept demonstration of free-form optics enhanced confocal Raman spectroscopy in combination with optofluidic lab-on-chip

Raman spectroscopy is a powerful optical and non-destructive technique and a well-known method for analysis purposes, especially to determine the molecular fingerprint of substances. Traditionally, such analyses are done in a specialized lab, with considerable requirements in terms of equipment, time and manual sampling of substances of interest. In this paper we take a step from bulky Raman spectroscopy laboratory analyses towards lab-on-chip (LOC) analyses. We present an optofluidic lab-on-chip for confocal Raman spectroscopy, which can be used for the analysis of liquids. The confocal detection suppresses the unwanted background from the polymer material out of which the chip is fabricated. We design the free-form optical reflector using non-sequential ray-tracing combined with a mathematical code to simulate the Raman scattering behavior of the substance under test. We prototype the device in Polymethyl methacrylate (PMMA) by means of ultraprecision diamond tooling. In a proof-of-concept demonstration, we first show the confocal behavior of our Raman lab-on-chip system by measuring the Raman spectrum of ethanol. In a next step, we compare the Raman spectra measured in our lab-on-chip with spectra measured with a commercial Raman spectrometer. Finally, to calibrate the system we perform Raman measurements on urea solutions with different concentrations. We achieve a detection limit that corresponds to a noise equivalent concentration of 20mM. Apart from strongly reducing the background perturbations, our confocal Raman spectroscopy system has other advantages as well. The reflector design is robust from a mechanical point of view and has the potential for mass-manufacturing using hot embossing or injection molding

Performance study of HGCROC-V2: the front-end electronics for the CMS High Granularity Calorimeter

The High Granularity Calorimeter (HGCAL), presently being designed by the Compact Muon Solenoid collaboration (CMS) to replace the existing endcap calorimeters for the High Luminosity phase of the LHC, will feature unprecedented transverse and longitudinal readout and triggering segmentation for both electromagnetic and hadronic sections. The requirements for the front-end electronics are extremely challenging, including high dynamic range (0-10 pC), low noise (~2000 electrons), high-precision timing information in order to mitigate the pileup effect (25 ps binning) and low power consumption (~15 mW/channel). The front-end electronics will face a harsh radiation environment which will reach 200 Mrad at the end of life. It will work at a controlled temperature of 240 K. HGCROV-V2 is the second prototype of the front-end ASIC. It has 72 channels of the full analog chain: low noise and high gain preamplifier and shapers, and a 10-bit 40 MHz SAR-ADC, which provides the charge measurement over the linear range of the preamplifier. In the saturation range of the preamplifier, a discriminator and TDC provide the charge information from TOT (Time Over Threshold) over 200 ns dynamic range using 50 ps binning. A fast discriminator and TDC provide timing information to 25 ps accuracy. Both charge and timing information are kept in a DRAM memory waiting for a Level 1-trigger decision (L1A). At a bunch crossing rate of 40 MHz, compressed charge data are sent out to participate in the generation of the L1-trigger primitives. We report on the performances of the chip in terms of signal-to-noise ratio, charge and timing, as well as results from radiation qualification with total ionizing dose (TID)

Test vehicles for CMS HGCAL readout ASIC

This paper presents first measurement results of two test vehicles ASIC embedding some building blocks for the future CMS High Granularity CALorimeter (HGCAL) read-out ASIC. They were fabricated in CMOS 130 nm, in order to first design the Analog and Mixed-Signal blocks before going to a complete and complex chip. Such a circuit needs to achieve low noise high dynamic range charge measurement and 20 ps resolution timing capability. The results show good analog performance but with higher noise levels compared to simulations. We present the results of the preamplifiers, shapers and ADCs

Irradiation Testing of HGCROC3: the Front-End Readout ASIC for the CMS High Granularity Calorimeter

International audienceThe HGCROC3 is the final version of the front-end ASIC designed to readout the 6 million channels of the future HGCAL detector. Along with cutting-edge specifications in terms of low noise, time measurement precision, and ability to contribute to the Level-1 trigger decision, one of the key requirements for the HGCROC3 is a high radiation tolerance.Several irradiation campaigns have been carried out on HGCROC3 prototypes, with particular emphasis on the Total Integrated Dose (TID) and the Single-Event Effect (SEE) tests. In the context of the TID campaign, results are presented in terms of power consumption, charge and time measurement performance, clocks, and serial links robustness. Although previous versions of the same ASIC architecture show encouraging results in terms of SEE hardness, in this final version of the chip a special care is taken to reach the radiation tolerance requirement for critical blocks such as the digital counters, the clocks and the serializers. The corresponding studies of SEE effects on these components are also reported in this contribution

Free-form optics enhanced confocal Raman spectroscopy for optofluidic lab-on-chips

We present an optofluidic lab-on-chip for confocal Raman spectroscopy, which can be used for analysis of substances. The device strongly suppresses unwanted background signals because it enables confocal detection of Raman scattering thanks to a free-form reflector embedded in the optofluidic chip. We design the system using non-sequential ray-tracing combined with a mathematical code to simulate the Raman scattering behavior of the substance under test. We prototype the device in Polymethyl methacrylate (PMMA) by means of ultraprecision diamond tooling. In a proof-of-concept demonstration, we first show the confocal behavior of our Raman lab-on-chip system by measuring the Raman spectrum of ethanol. In a next step, we compare Raman spectra measured in our lab-on-chip with spectra measured with a commercial Raman spectrometer. Finally, to calibrate the system we perform Raman measurements on urea solutions with different concentrations with our proposed experimental proof-of-concept setup. We achieved a detection limit that corresponds to the noise equivalent concentration of 20mM

A Three-Step Low-Power Multichannel TDC Based on Time Residual Amplifier

International audienceThis article proposes and evaluates an architecture for a low-power time-to-digital converter (TDC) with high resolution, optimized for high-rate operation (40 MSa/channel), and integration with analog front end in multichannel readout chips in 130-nm CMOS technology. The converter is based on a three-step architecture. The first step uses a counter and the following ones are based on two types of delay-line (DL) structures. A programmable time amplifier (TA) is used between the second and third steps to reach a final resolution of 24.4 ps in the standard mode of operation. In addition, this architecture uses common continuously stabilized reference blocks that control the channels against the effects of global process, voltage, and temperature (PVT) variations. We also propose a per-channel DL gain correction based on a trimmable block to correct the mismatch effect. The area of the TDC channel is only 0.051 mm2. For a 40-MSa/channel rate, the TDC average power consumption measured per channel is 2.2 mW for a 100% hit occupancy and decreases to 311 $\mu \text{W}$ for the 10% occupancy specified for our main application. The demonstrated compactness and low power consumption fully match our requirements for integration into multichannel front-end chips. The experimental results demonstrate good timing performance over a broad range of operating temperatures (-35 degrees C and 65 degrees C), which conforms to our expectations. For example, the measured timing integral nonlinearity (INL) is better than +/- 1 LSB (+/- 25 ps), and the overall timing precision is better than 21-ps rms

SET sensitivity of a VCRO-based PLL for HL-LHC ATLAS HGTD

International audienceWe report the characterization of the Single Effect Transient (SET) sensitivity of an analogue Phase Locked Loop (PLL) based on a Voltage Controlled Ring Oscillator (VCRO) under a proton beam. The clock generator is embedded in a front-end ASIC, namely ALTIROC designed in CMOS 130 nm, reading out Low-Gain Avalanche Diode (LGAD) matrices for the High-Luminosity Large Hadron Collider (HL-LHC). We detail the methodology developed to study such events that could degrade the targeted time resolution of 35 ps per hit. Observed SET-induced phase jumps allow the estimation of the total cross-section of the PLL. The results are extrapolated to the HL-LHC radiation conditions

An Integrated Care Platform System (C3-Cloud) for Care Planning, Decision Support, and Empowerment of Patients With Multimorbidity: Protocol for a Technology Trial

Background: There is an increasing need to organize the care around the patient and not the disease, while considering the complex realities of multiple physical and psychosocial conditions, and polypharmacy. Integrated patient-centered care delivery platforms have been developed for both patients and clinicians. These platforms could provide a promising way to achieve a collaborative environment that improves the provision of integrated care for patients via enhanced information and communication technology solutions for semiautomated clinical decision support. Objective: The Collaborative Care and Cure Cloud project (C3-Cloud) has developed 2 collaborative computer platforms for patients and members of the multidisciplinary team (MDT) and deployed these in 3 different European settings. The objective of this study is to pilot test the platforms and evaluate their impact on patients with 2 or more chronic conditions (diabetes mellitus type 2, heart failure, kidney failure, depression), their informal caregivers, health care professionals, and, to some extent, health care systems. Methods: This paper describes the protocol for conducting an evaluation of user experience, acceptability, and usefulness of the platforms. For this, 2 “testing and evaluation” phases have been defined, involving multiple qualitative methods (focus groups and surveys) and advanced impact modeling (predictive modeling and cost-benefit analysis). Patients and health care professionals were identified and recruited from 3 partnering regions in Spain, Sweden, and the United Kingdom via electronic health record screening. Results: The technology trial in this 4-year funded project (2016-2020) concluded in April 2020. The pilot technology trial for evaluation phases 3 and 4 was launched in November 2019 and carried out until April 2020. Data collection for these phases is completed with promising results on platform acceptance and socioeconomic impact. We believe that the phased, iterative approach taken is useful as it involves relevant stakeholders at crucial stages in the platform development and allows for a sound user acceptance assessment of the final product. Conclusions: Patients with multiple chronic conditions often experience shortcomings in the care they receive. It is hoped that personalized care plan platforms for patients and collaboration platforms for members of MDTs can help tackle the specific challenges of clinical guideline reconciliation for patients with multimorbidity and improve the management of polypharmacy. The initial evaluative phases have indicated promising results of platform usability. Results of phases 3 and 4 were methodologically useful, yet limited due to the COVID-19 pandemic