Microstrip Readout Research Articles

Recent developments in the CBC3, a CMS micro-strip readout ASIC for track-trigger modules at the HL-LHC

Abstract The CMS Binary Chip (CBC) is the front-end readout ASIC planned for the outermost layers of the CMS Phase 2 silicon outer tracker. Results from an extensive irradiation campaign carried out on the CBC3, the first version of the ASIC to include the full trigger logic circuitry, have demonstrated that the chip is capable of withstanding the levels of radiation expected at the HL-LHC, with only a slight ( 1 % ) increase in power consumption. Results from the irradiation campaign, and details of the novel damage model developed to describe the measurements and extrapolate to the final operating conditions, will be presented. Additionally, results from tests at the Fermilab test beam facility will be shown that demonstrate the full functionality of the trigger logic.

Study of Surface Roughness Effect on Super–Normal Transition of Ti/Au Transition Edge Sensor Calorimeters

We are developing transition edge sensor (TES) X-ray microcalorimeters for the future Japanese mission DIOS. It adopts microstrip readout wiring for low pixel-to-pixel crosstalk. In past samples, TES films composed of Ti and Au have not shown proper super–normal transition when it is deposited on the wiring. Assuming that surface roughness of the substrate can influence the transition, we reduced the surface roughness of the underneath layer before deposition of the TES film by using chemical mechanical polishing. We then found that the substrate becomes much smoother with a roughness of <1 nm rms and the TES film shows a proper transition.

Photon counting microstrip X-ray detectors with GaAs sensors

High-Z sensors are increasingly used to overcome the poor efficiency of Si sensors above 15 keV, and further extend the energy range of synchrotron and FEL experiments. Detector-grade GaAs sensors of 500 μm thickness offer 98% absorption efficiency at 30 keV and 50% at 50 keV . In this work we assess the usability of GaAs sensors in combination with the MYTHEN photon-counting microstrip readout chip developed at PSI. Different strip length and pitch are compared, and the detector performance is evaluated in regard of the sensor material properties. Despite increased leakage current and noise, photon-counting strips mounted with GaAs sensors can be used with photons of energy as low as 5 keV, and exhibit excellent linearity with energy. The charge sharing is doubled as compared to silicon strips, due to the high diffusion coefficient of electrons in GaAs.

Simulation of the GEM detector for BM@N experiment

The Gas Electron Multiplier (GEM) detector is one of the basic parts of the BM@N experiment included in the NICA project. The simulation model that takes into account features of signal generation process in an ionization GEM chamber is presented in this article. Proper parameters for the simulation were extracted from data retrieved with the help of Garfield++ (a toolkit for the detailed simulation of particle detectors). Due to this, we are able to generate clusters in layers of the micro-strip readout that correspond to clusters retrieved from a real physics experiment.

The design and performance of a prototype water Cherenkov optical time-projection chamber

A first experimental test of tracking relativistic charged particles by ‘drifting’ Cherenkov photons in a water-based optical time-projection chamber (OTPC) has been performed at the Fermilab Test Beam Facility. The prototype OTPC detector consists of a 77cm long, 28cm diameter, 40kg cylindrical water mass instrumented with a combination of commercial 5.1×5.1cm2 micro-channel plate photo-multipliers (MCP-PMT) and 6.7×6.7cm2 mirrors. Five MCP-PMTs are installed in two columns along the OTPC cylinder in a small-angle stereo configuration. A mirror is mounted opposite each MCP-PMT on the inner surface of the detector cylinder, effectively increasing the photo-detection efficiency and providing a time-resolved image of the Cherenkov light on the opposing wall. Each MCP-PMT is coupled to an anode readout consisting of thirty 50Ω microstrips. A 180-channel data acquisition system digitizes the MCP-PMT signals on one end of the microstrips using the PSEC4 waveform sampling-and-digitizing chip operating at a sampling rate of 10.24Gigasamples-per-second. The single-ended microstrip readout determines the time and position of a photon arrival at the face of the MCP-PMT by recording both the direct signal and the pulse reflected from the unterminated far end of the strip. The detector was installed on the Fermilab MCenter secondary beam-line behind a steel absorber where the primary flux is multi-GeV muons. Approximately 80 Cherenkov photons are detected for a through-going muon track in a total event duration of ~2ns. By measuring the time-of-arrival and the position of individual photons at the surface of the detector to ≤100ps and a few mm, respectively, we have measured a spatial resolution of ~15mm for each MCP-PMT track segment, and, from linear fits over the entire track length of ~40cm, an angular resolution on the track direction of ~60mrad.

Performance of a Micro-Strip Gas Chamber for event wise, high rate thermal neutron detection with accurate 2D position determination

A two-dimensional (2D) position sensitive detector for neutron scattering applications based on low-pressure gas amplification and micro-strip technology was built and tested with an innovative readout electronics and data acquisition system. This detector contains a thin solid neutron converter and was developed for time- and thus wavelength-resolved neutron detection in single-event counting mode, which improves the image contrast in comparison with integrating detectors. The prototype detector of a Micro-Strip Gas Chamber (MSGC) was built with a solid natGd/CsI thermal neutron converter for spatial resolutions of about 100 μm and counting rates up to 107 neutrons/s. For attaining very high spatial resolutions and counting rates via micro-strip readout with centre-of-gravity evaluation of the signal amplitude distributions, a fast, channel-wise, self-triggering ASIC was developed. The front-end chips (MSGCROCs), which are very first signal processing components, are read out into powerful ADC-FPGA boards for on-line data processing and thereafter via Gigabit Ethernet link into the data receiving PC. The workstation PC is controlled by a modular, high performance dedicated software suite. Such a fast and accurate system is crucial for efficient radiography/tomography, diffraction or imaging applications based on high flux thermal neutron beam.In this paper a brief description of the detector concept with its operation principles, readout electronics requirements and design together with the signals processing stages performed in hardware and software are presented. In more detail the neutron test beam conditions and measurement results are reported. The focus of this paper is on the system integration, two dimensional spatial resolution, the time resolution of the readout system and the imaging capabilities of the overall setup. The detection efficiency of the detector prototype is estimated as well.

CBC2: A CMS microstrip readout ASIC with logic for track-trigger modules at HL-LHC

The CBC2 is the latest version of the CMS Binary Chip ASIC for readout of the upgraded CMS Tracker at the High Luminosity LHC. It is designed in 130nm CMOS with 254 input channels and will be bump-bonded to a substrate to which sensors will be wire-bonded. The CBC2 is designed to instrument double layer modules, consisting of two overlaid silicon microstrip sensors with aligned microstrips, in the outer tracker. It incorporates logic to identify L1 trigger primitives in the form of “stubs”: high transverse-momentum track candidates which are identified within the low momentum background by selecting correlated hits between two closely separated microstrip sensors. The first prototype modules have been assembled. The performance of the chip in recent laboratory tests is briefly reported and the status of module construction described.

CBC2: a microstrip readout ASIC with coincidence logic for trigger primitives at HL-LHC

We present the design of CBC2, the new version of the CMS Binary Chip ASIC for the readout of CMS Tracker Phase-two upgrade. CBC2, designed in 130nm CMOS, doubles the input channels to 254 and will be bump-bonded to the substrate. The ASIC is designed to instrument double layer modules in the outer tracker, consisting of two overlaid silicon sensors with aligned microstrips, and incorporates the logic to identify L1 trigger primitives in the form of ``stubs'': high transverse-momentum candidates which are isolated from the low momentum background by selecting correlated hits between two closely separated microstrip sensors. The functionality of the coincidence logic, which includes rejection of wide clusters and offset correction to account for the position of the module in the R-ϕ plane, is described in detail.

The CBC microstrip readout chip for CMS at the High Luminosity LHC

The CMS Binary Chip (CBC) is designed for readout of silicon microstrips in the CMS Tracker at the High Luminosity LHC (HL-LHC). Binary, unsparsified readout is well suited to the high luminosity environment, where particle fluences and data rates will be much higher than at the LHC. In September 2011, a module comprising a CBC bonded to a silicon microstrip sensor was tested with 400 GeV protons in the H8 beamline at CERN. Performance was in agreement with expectations. The spatial resolution of the sensor and CBC has been shown to be better than pitch/√12 due to spatial distribution of one and two strip clusters. Large cluster events show consistency with the production of delta rays. At operating thresholds, the hit efficiency has been shown to be approximately 98%, limited by the resolution of timing apparatus, while the noise occupancy is measured to be below 10−4. The distribution of charge deposition in the sensor has been reconstructed by measurement of the hit efficiency as a function of comparator threshold; assuming the underlying distribution is a Landau.

The CMS binary chip for microstrip tracker readout at the SLHC

A 130 nm CMOS chip has been designed for silicon microstrip readout at the SLHC. The CBC has 128 channels, and utilises a binary un-sparsified architecture for chip and system simplicity. It is designed to read out signals of either polarity from short strips (capacitances up to ∼ 10 pF) and can sink or source sensor leakage currents up to 1 μA. Details of the design and measured performance are presented.

Investigation and Optimization of LEKID Coupling Structures and Multi-Pixel Arrays at 4.2 K

The development of large multi-pixel detector applications with lumped element kinetic inductance detectors (LEKID) requires a detailed knowledge about the mode of operation in respect of the microwave regime. In this paper the basic properties of LEKID structures for applications at liquid helium temperatures were investigated. In consideration of the operation temperature, the different microwave behavior of LEKID structures coupled to microstrip and coplanar strip readout transmission lines, e.g. loaded and unloaded quality factors, have been examined. For this purpose several test structures, which are suitable for large arrays, in multi-pixel applications, were designed and characterized with frequency around 6 GHz. Loaded quality factors QL up to 10,000 at 4.2 K were achieved. The devices were fabricated in niobium thin film technology on silicon substrates. LEKID arrays with 3 resonators were designed, fabricated and measured with our self-developed FDM readout system. The results of the measurements will be presented and discussed.

Development of the gas electron multiplier (GEM)

We describe recent developments of the gas electron multiplier (GEM), a thin composite mesh acting as proportional avalanche amplifier in gas counters. In beam tests we have verified the excellent efficiency, time resolution and localization accuracy for a GEM with micro-strip read-out. Efficiency, localization accuracy and operation in strong magnetic fields has been verified; operation at rates above 10/sup 6/ Hz/mm/sup 2/ and lifetimes corresponding to at least 10 mC/cm of collected charge have been demonstrated. Refinements in the manufacturing technology have permitted the realization of large size detectors (27 by 25 cm/sup 2/), to be used in conjunction with microstrip gas chambers. With an improved design, stable gains above two thousand have been reached (GEM2000); larger gains can be obtained increasing the thickness of the foils, cascading two GEMs at some distance or in electrical contact. Further developments of the technology and prospective applications are discussed.

Resistive plate chambers with secondary electron emitters and microstrip readout

We describe our attempt to develop Resistive Plate Chambers (RPCs). One study involves the use of secondary electron emitters that consist of porous photosensitive materials (CsI, diethylferocenil-mercury, SbCs and others) deposited on a cathode; this enhances efficiency, thus allowing the use of light, non-flammable gas mixtures. The other study concerns the operation of an RPC with a narrow strip readout - the “microstrip RPC”.

A time projection chamber with microstrip read-out

The design and testing of a novel detector for heavy-ion physics in the intermediate-energy regime is described. This detector consists of a large drift chamber with microstrip read-out in combination with thick plastic scintillators. With this system particle identification and energy determination with high spatial resolution and multiple hit capacity is achieved.

Front end electronics for silicon tracking at LHC

A CMOS front end electronics chain is being developed by the RD20 collaboration in a CERN R&D programme for silicon microstrip readout at LHC. It is based on a preamplifier and CR-RC filter, analogue pipeline and an analogue signal processor which implements a deconvolution algorithm. The system is described and latest results on performance presented, including the status of implementation in radiation hard technology.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>