Readout Components Research Articles

Radiopurity assessment of the tracking readout for the NEXT double beta decay experiment

The ``Neutrino Experiment with a Xenon Time-Projection Chamber'' (NEXT) is intended to investigate the neutrinoless double beta decay of 136Xe, which requires a severe suppression of potential backgrounds; therefore, an extensive screening and selection process is underway to control the radiopurity levels of the materials to be used in the experimental set-up of NEXT. The detector design combines the measurement of the topological signature of the event for background discrimination with the energy resolution optimization. Separate energy and tracking readout planes are based on different sensors: photomultiplier tubes for calorimetry and silicon multi-pixel photon counters for tracking. The design of a radiopure tracking plane, in direct contact with the gas detector medium, was specially challenging since the needed components like printed circuit boards, connectors, sensors or capacitors have typically, according to available information in databases and in the literature, activities too large for experiments requiring ultra-low background conditions. Here, the radiopurity assessment of tracking readout components based on gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterr'aneo de Canfranc (Spain) is described. According to the obtained results, radiopure enough printed circuit boards made of kapton and copper, silicon photomultipliers and other required components, fulfilling the requirement of an overall background level in the region of interest of at most 8×10−4 counts keV−1 kg−1 y−1, have been identified.

Performance of a novel wafer scale CMOS active pixel sensor for bio-medical imaging

Recently CMOS active pixels sensors (APSs) have become a valuable alternative to amorphous silicon and selenium flat panel imagers (FPIs) in bio-medical imaging applications. CMOS APSs can now be scaled up to the standard 20 cm diameter wafer size by means of a reticle stitching block process. However, despite wafer scale CMOS APS being monolithic, sources of non-uniformity of response and regional variations can persist representing a significant challenge for wafer scale sensor response. Non-uniformity of stitched sensors can arise from a number of factors related to the manufacturing process, including variation of amplification, variation between readout components, wafer defects and process variations across the wafer due to manufacturing processes. This paper reports on an investigation into the spatial non-uniformity and regional variations of a wafer scale stitched CMOS APS. For the first time a per-pixel analysis of the electro-optical performance of a wafer CMOS APS is presented, to address inhomogeneity issues arising from the stitching techniques used to manufacture wafer scale sensors. A complete model of the signal generation in the pixel array has been provided and proved capable of accounting for noise and gain variations across the pixel array. This novel analysis leads to readout noise and conversion gain being evaluated at pixel level, stitching block level and in regions of interest, resulting in a coefficient of variation ⩽1.9%. The uniformity of the image quality performance has been further investigated in a typical x-ray application, i.e. mammography, showing a uniformity in terms of CNR among the highest when compared with mammography detectors commonly used in clinical practice. Finally, in order to compare the detection capability of this novel APS with the technology currently used (i.e. FPIs), theoretical evaluation of the detection quantum efficiency (DQE) at zero-frequency has been performed, resulting in a higher DQE for this detector compared to FPIs. Optical characterization, x-ray contrast measurements and theoretical DQE evaluation suggest that a trade off can be found between the need of a large imaging area and the requirement of a uniform imaging performance, making the DynAMITe large area CMOS APS suitable for a range of bio-medical applications.

A Novel Indirect Sequence Readout Component in the E. coli Cyclic AMP Receptor Protein Operator

The cyclic AMP receptor protein (CRP) from Escherichia coli has been extensively studied for several decades. In particular, a detailed characterization of CRP interaction with DNA has been obtained. The CRP dimer recognizes a consensus sequence AANTGTGANNNNNNTCACANTT through direct amino acid nucleobase interactions in the major groove of the two operator half-sites. Crystal structure analyses have revealed that the interaction results in two strong kinks at the TG/CA steps closest to the 6-base-pair spacer (N6). This spacer exhibits high sequence variability among the more than 100 natural binding sites in the E. coli genome, but the exact role of the N6 region in CRP interaction has not previously been systematic examined. Here we employ an in vitro selection system based on a randomized N6 spacer region to demonstrate that CRP binding to the lacP1 site may be enhanced up to 14-fold or abolished by varying the N6 spacer sequences. Furthermore, on the basis of sequence analysis and uranyl (UO2(2+)) probing data, we propose that the underlying mechanism relies on N6 deformability.

Effect of 8-Oxoguanine on DNA Structure and Deformability

8-Oxoguanine (oxoG) is an abundant product of oxidative DNA damage. It is removed by repair glycosylases, but exactly how the enzymes recognize oxoG in the large surplus of undamaged bases is not fully understood. The lesion may induce changes in the properties of naked DNA that facilitate the recognition. In this work, we assess the effect of oxoG on DNA structure and mechanical deformability. We performed extensive unrestrained, atomic resolution molecular dynamics simulations to parametrize a nonlocal, rigid base mechanical model of DNA. Our data indicate that oxoG induces unwinding of the base pair step at the 5'-side of the lesion. This brings the damaged DNA closer to its conformation in the initial complex with bacterial glycosylase MutM. The untwisting is partially caused by different BII substate populations and is further enhanced by the base-sugar repulsion within oxoG. On the other hand, our analysis shows that damaged and undamaged DNA have very similar harmonic stiffness. These results suggest an indirect readout component of the MutM-DNA initial complex formation. They also help one to understand the effect of oxoG on the formation of nucleosomes and looped gene regulatory complexes.

A vertical electro-optical data cable for KM3NeT

KM3NeT is a research facility which will be built at the bottom of the Mediterranean Sea. The facility will host a neutrino telescope with several hundred detection units—vertical mechanical structures to which the optical sensors modules of the telescope are attached. A data cable will run the full length of the structure. In order to allow for a compact deployment of the detection unit, the cable must be flexible and at the same time protect the two copper conductors and eleven optical fibres inside. To comply with these requirements a pressure balanced oil filled cable has been designed, for which a prototype is being built for in situ tests at the anticipated telescope depths of 3–5km. At the level of each optical sensor module a short horizontal cable breaks out which is connected to the readout components inside the glass sphere of the module via a novel tapered glass transit. We will present the design and assembly method of the cable, the design of the glass transit and the results of laboratory tests.

A new gamma camera with a Gas Electron Multiplier

We have developed a prototype gaseous gamma camera with a Gas Electron Multiplier (GEM) for biomolecular analysis and medical applications. The system consists of three devices: a detector, an Ethernet hub, and a PC. The detector consists of a GEM-chamber and integrated readout electronics. The GEM-chamber consists of three parts: the gamma-ray conversion and amplification layers consisting of GEM foils, and a readout component. To increase gamma-ray-detection efficiency, we constructed a new type of GEM foil. The gamma-ray conversion layers are plated with gold 3 μm thick on both surfaces. In order to test the performance of the prototype camera, several measurements were performed with a phantom filled with 99mTc (141 keV) as the radioactive source, and two-dimensional (2D) images were obtained using a pinhole collimator. The camera showed good capability to resolve objects of a few mm2. We believe that this system will offer new knowledge in biomolecular analysis and medical applications.

Studies on sampling and homogeneous dual readout calorimetrywith meta-crystals

The meta-crystals concept is an approach that consists of using both undoped and properly doped heavy crystal fibers of identical material as the active medium of a calorimeter. The undoped fibers behave as Cherenkov radiators while the doped ones behave as scintillators. A dual readout calorimeter can be built with its sensitive volume composed of a mixture of both types of crystals. In addition if the calorimeter is adequately finely segmented it can also function as a particle flow calorimeter at the same time.In this way one could possibly combine the advantages of both the particle flow concept and the dual readout scheme.We discuss the approach of dual readout calorimetry with meta-crystals made of Lutetium Aluminium Garnet (LuAG).We briefly present studies on the material development and first testbeam activities and then focus on performance expectation studies based on simulation. We discuss in more detail the results from generic systematic scannings of the design parameters of a dual readout calorimeter. The parameters under study include the transverse and longitudinal granularity, the sampling frequency and readout fraction of the scintillation and the Cherenkov signals, the total calorimeter length, the mixture of homogeneous and sampling dual readout components, their corresponding composition etc. We close with a brief outlook on open issues and further R&D needed to proceed from an ideal conceptual case to the design of a realistic detector.

Development of DAQ-Middleware

DAQ-Middleware is a software framework of network-distributed DAQ system based on Robot Technology Middleware, which is an international standard of Object Management Group (OMG) in Robotics and its implementation was developed by AIST. DAQ-Component is a software unit of DAQ-Middleware. Basic components have been already developed. For examples, Gatherer is a readout component, Logger is a data logging component, Monitor is an analysis component and Dispatcher, which is connected to Gatherer as input of data path and to Logger/Monitor as output of data path. DAQ operator is a special component, which controls those components by using the control/status path. The control/status path and data path as well as XML-based system configuration and XML/HTTP-based system interface are well defined in DAQ-Middleware framework. DAQ-Middleware was adopted by experiments at J-PARC while the commissioning at the first beam had been successfully carried out. The functionality of DAQ-Middleware and the status of DAQ-Middleware at J-PARC are presented.

A re-configurable sigma-delta modulator for use with capacitive sensors

Capacitive sensors have different configurations depending on their fabrication; some sensors are a simple single capacitor while others provide a differential structure. A readout component needs to be flexible to adapt to these different structures. Capacitance to voltage conversion based on sigma-delta techniques [1] provides a precise and high resolution method for readout but current implementations can be fixed to a particular sensor configuration. This paper describes the design of a re-configurable sigma-delta front end able to interface with a large range of MEMS capacitive sensors (accelerometers and pressure), humidity sensors and capacitive level and position sensors. The design has been realized in silicon and performance of the readout system with a number of different types of capacitive sensors is described and results are presented.

Diffusion-weighted single-shot echo planar MR imaging of normal human prostate using different b values

This study examined the effect of different b values on diffusion-weighted MR imaging (DWI) of human prostate by using single-shot spin echo echo planar imaging (SE-EPI) sequences, observed the normal appearances and measured apparent diffusion coefficient (ADC) values in anatomical regions of normal prostate. Twenty-four healthy volunteers (mean age: 32 y) were studied by using a 1.5T system with a phased array surface multicoil. Two kinds of single-shot SE-EPI sequence were used to perform DWI in the prostate in volunteers, with five b values being 0, 30, 300, 500 to 1000 s/mm(2). The image quality with different imaging parameters was analyzed and the ADC values in anatomical regions of normal prostate were measured. DWI of prostate was successfully obtained in all volunteers. The images were of good quality, without artifacts containing pixels within the prostate. The contrast was good between the different anatomical regions of the prostatic gland, i.e., the peripheral zone (PZ), which exhibited higher signal intensity, and the central gland (CG). Signal intensity contrast was related to the magnitude of b values. The ADC values in PZ and CG were (1.27+/-0.22)x10(-3) mm(2)/s and (1.01+/-0.17)x10(-3) mm(2)/s, respectively. The ADC values were found to be significantly higher in PZ than in CG (P<0.05, paired t-test). Significant differences were found between the slice-selecting component and both the read-out and phase-encoding components of the ADC values. It is concluded that SE-EPI is a suitable DWI sequence for human prostate. The contrast between PZ and CG is good when b values are low, while the diffusion and ADC values are accurate when b values are high. ADC values are higher in PZ than in CG in normal prostate. Diffusional anisotropy is present in normal prostatic tissue.

Data Acquisition Backbone Core DABC

For the new experiments at FAIR new concepts of data acquisition systems have to be developed like the distribution of self-triggered, time stamped data streams over high performance networks for event building. The Data Acquisition Backbone Core (DABC) is a software package currently under development for FAIR detector tests, readout components test, and data flow investigations. All kinds of data channels (front-end systems) are connected by program plug-ins into functional components of DABC like data input, combiner, scheduler, event builder, analysis and storage components. After detailed simulations real tests of event building over a switched network (InfiniBand clusters with up to 110 nodes) have been performed. With the DABC software more than 900 MByte/s input and output per node can be achieved meeting the most demanding requirements. The software is ready for the implementation of various test beds needed for the final design of data acquisition systems at FAIR. The development of key components is supported by the FutureDAQ project of the European Union (FP6 I3HP JRA1).

Data Acquisition Backbone Core DABC

For the new experiments at FAIR new concepts of data acquisition systems have to be developed like the distribution of self-triggered, time stamped data streams over high performance networks for event building. The Data Acquisition Backbone Core (DABC) is a software package designed for FAIR detector tests, readout components test, and data flow investigations. All kinds of data channels (front-end systems) are connected by program plug-ins into functional components of DABC like data input, combiner, scheduler, event builder, analysis and storage components. After detailed simulations real tests of event building over a switched network (InfiniBand clusters with up to 23 nodes) have been performed. With the DABC software more than 900 MByte/s input and output per node can be achieved meeting the most demanding requirements. The software is ready for the implementation of various test beds needed for the final design of data acquisition systems at FAIR.

A Nanoparticle-Based Solution DNA Sandwich Assay Using ICP-AES for Readout

We report herein a nanoparticle-based methodology for detecting DNA in solution using inductively coupled plasma atomic emission spectrometry (ICP-AES) as a readout tool. This represents the first homogeneous solution assay of biologically significant targets by employing ICP-related techniques. Two types of particles are employed: silica nanoparticles or gold nanoparticles functionalized with oligonucleotides that are capable of hybridizing with half of the target DNA sequence as signal readout components, and magnetic microparticles functionalized with oligonucleotides that are capable of hybridizing with the other half of the sequence as capture components. In the presence of target DNA, three components form typical sandwich structures, and the application of a magnetic field could effectively separate them from the rest of the solution. Subsequent application of ICP-AES effectively provides an inorganic elemental readout for the diagnosis of target DNA.

Investigation of DNA Decorated Carbon Nanotube Chemical Sensors

ABSTRACTWe demonstrate a versatile class of nanoscale sensors based on single-stranded DNA (ss-DNA) as the chemical recognition site and single-walled carbon nanotube field effect transistors (swCN-FETs) as the electronic readout component. Coating swCN-FETs with ss-DNA causes a current change when exposed to gaseous analytes, whereas bare swCN-FETs show no detectable change. The responses differ in sign and magnitude depending both on the type of gaseous analyte and the sequence of DNA. Our results suggest that the conformation of ss-DNA on swCN-FET plays a role in determining the sensor response to gaseous analytes. The conformation depends not only on the base content of the oligomer, but also on the specific arrangement of the bases in the ss-DNA. We compare our results with the molecular dynamic simulations for understanding of the sensing mechanisms. SsDNA/swCN-FETs possess rapid recovery and self-regenerating ability, which could lead to realization of large arrays for sensitive electronic olfaction and disease diagnosis.

Free Energy Contributions to Direct Readout of a DNA Sequence

The energetic contributions of individual DNA-contacting side chains to specific DNA recognition in the human papillomavirus 16 E2C-DNA complex is small (less than 1.0 kcal mol(-1)), independent of the physical and chemical nature of the interaction, and is strictly additive. The sum of the individual contributions differs 1.0 kcal mol(-1) from the binding energy of the wild-type protein. This difference corresponds to the contribution from the deformability of the DNA, known as "indirect readout." Thus, we can dissect the energetic contribution to DNA binding into 90% direct and 10% indirect readout components. The lack of high energy interactions indicates the absence of "hot spots," such as those found in protein-protein interfaces. These results are compatible with a highly dynamic and "wet" protein-DNA interface, yet highly specific and tight, where individual interactions are constantly being formed and broken.

DNA-Decorated Carbon Nanotubes for Chemical Sensing

We demonstrate a new, versatile class of nanoscale chemical sensors based on single-stranded DNA (ss-DNA) as the chemical recognition site and single-walled carbon nanotube field effect transistors (swCN-FETs) as the electronic read-out component. swCN-FETs with a nanoscale coating of ss-DNA respond to gas odors that do not cause a detectable conductivity change in bare devices. Responses of ss-DNA/swCN-FETs differ in sign and magnitude for different gases and can be tuned by choosing the base sequence of the ss-DNA. ss-DNA/swCN-FET sensors detect a variety of odors, with rapid response and recovery times on the scale of seconds. The sensor surface is self-regenerating: samples maintain a constant response with no need for sensor refreshing through at least 50 gas exposure cycles. This remarkable set of attributes makes sensors based on ss-DNA decorated nanotubes very promising for "electronic nose" and "electronic tongue" applications ranging from homeland security to disease diagnosis.

Single Stranded DNA Decorated Carbon Nanotube Transistors for Chemical Sensing

ABSTRACTWe demonstrate that single walled carbon nanotube field effect transistors (swCN-FET) decorated with single stranded DNA (ss-DNA) form a new, versatile, and highly sensitive class of nanoscale chemical sensors. These sensors are based on ss-DNA as the chemical recognition site and swCN-FET as the electronic read-out component. The ss-DNA decorated swCN-FETs are sensitive to chemical species (odors) that do not cause a detectable response in bare, as-fabricated swCN-FETs. Furthermore, odor responses ss-DNA decorated FETs differ in sign and magnitude for different odors, and the response characteristics depend on the base sequence of the ss-DNA used to decorate the swCN. The sensor surface is self-regenerating: samples maintain a constant response with no need for sensor refreshing through at least several dozens gas exposure cycles. These remarkable attributes suggest that DNA-decorated swCN-FET sensors could be created with sensitivity to a large variety of compounds, as required for “electronic-nose” and “electronic tongue” applications in medicine and homeland security.

The CMS silicon strip tracker—systems aspects

A brief description of the CMS tracker and its sub-systems will be given. The performance of the silicon strip modules integrated into larger structures (up to 28 modules) will be described, with emphasis on the achieved signal-to-noise ratio for the chosen system components. These components include the mechanical support, cooling system, power supply, cabling, interconnect boards and grounding scheme. The final optical read-out and control components are used. Results from laboratory system tests and dedicated beam tests will be presented.

The CMS silicon strip tracker—systems aspects

A brief description of the CMS tracker and its sub-systems will be given. The performance of the silicon strip modules integrated into larger structures (up to 28 modules) will be described, with emphasis on the achieved signal-to-noise ratio for the chosen system components. These components include the mechanical support, cooling system, power supply, cabling, interconnect boards and grounding scheme. The final optical read-out and control components are used. Results from laboratory system tests and dedicated beam tests will be presented.

Parallel-Processing Diagnostic Program for a Transputer-Based Readout System

A parallel-processing program for system-diagnostic purposes was developed for a transputer-based readout system of a silicon vertex detector (SVD). The data-acquisition (DAQ) system for SVD was constructed as a part of research and development work for the BELLE [name of a detector for an asymmetric collider experiment at High Energy Accelerator Research Organization (KEK)] experiment consisting of data scanners (DS), slave memory modules (SMM) and direct memory access master modules (DMM). The DS, SMM and DMM have a transputer as a core processor. Each transputer was linked by a point-to-point connection with transputer serial interfaces (Inmos-link). The DAQ system was equipped with a transputer network system with the Inmos-links. The diagnostic program has the capability to detect malfunctioning readout components. To minimize the processing time during an experiment, the program runs in parallel on each transputer. For this purpose, the program was written using the programming language, occam. With the benefits of its distributed system architecture and without the need for any operating system, the program is compact with high modularity. In this paper, we report the system architecture of this diagnostic program.