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10th International “Hiroshima” Symposium on the Development and Application of Semiconductor Tracking Detectors, HSTD10, Xian, China, 25 Sep 2015 - 29 Sep 2015 ; Nuclear instruments & methods in physics research / A 831, 207 - 212(2016). doi:10.1016/j.nima.2016.04.044, The upgrade to the High-Luminosity LHC foreseen in about ten years represents a great challenge for the ATLAS inner tracker and the silicon strip sensors in the forward region. Several strip sensor designs were developed by the ATLAS collaboration and fabricated by Hamamatsu in order to maintain enough performance in terms of charge collection efficiency and its uniformity throughout the active region. Of particular attention, in the case of a stereo-strip sensor, is the area near the sensor edge where shorter strips were ganged to the complete ones. In this work the electrical and charge collection test results on irradiated miniature sensors with forward geometry are presented. Results from charge collection efficiency measurements show that at the maximum expected fluence, the collected charge is roughly halved with respect to the one obtained prior to irradiation. Laser measurements show a good signal uniformity over the sensor. Ganged strips have a similar efficiency as standard strips., Published by Elsevier, Amsterdam

The ATLAS group has evaluated the charge collection in silicon microstrip sensors irradiated up to a fluence of 1×1016 n eq /cm 2 , exceeding the maximum of 1.6×1015 n eq /cm 2 expected for the strip tracker during the high luminosity LHC (HL-LHC) period including a safety factor of 2. The ATLAS12, n + -on-p type sensor, which is fabricated by Hamamatsu Photonics (HPK) on float zone (FZ) substrates, is the latest barrel sensor prototype. The charge collection from the irradiated 1×1 cm 2 barrel test sensors has been evaluated systematically using penetrating β-rays and an Alibava readout system. The data obtained at different measurement sites are compared with each other and with the results obtained from the previous ATLAS07 design. The results are very consistent, in particular, when the deposit charge is normalized by the sensor's active thickness derived from the edge transient current technique (edge-TCT) measurements. The measurements obtained using β-rays are verified to be consistent with the measurements using an electron beam. The edge-TCT is also effective for evaluating the field profiles across the depth. The differences between the irradiated ATLAS07 and ATLAS12 samples have been examined along with the differences among the samples irradiated with different radiation sources: neutrons, protons, and pions. The studies of the bulk properties of the devices show that the devices can yield a sufficiently large signal for the expected fluence range in the HL-LHC, thereby acting as precision tracking sensors.

A radiation hard n+-in-p micro-strip sensor for the use in the Upgrade of the strip tracker of the ATLAS experiment at the High Luminosity Large Hadron Collider (HL-LHC) has been developed by the “ATLAS ITk Strip Sensor collaboration” and produced by Hamamatsu Photonics. Surface properties of different types of end-cap and barrel miniature sensors of the latest sensor design ATLAS12 have been studied before and after irradiation. The tested barrel sensors vary in “punch-through protection” (PTP) structure, and the end-cap sensors, whose stereo-strips differ in fan geometry, in strip pitch and in edge strip ganging options. Sensors have been irradiated with proton fluences of up to 1×1016 neq/cm2, by reactor neutron fluence of 1×1015 neq/cm2 and by gamma rays from 60Co up to dose of 1 MGy. The main goal of the present study is to characterize the leakage current for micro-discharge breakdown voltage estimation, the inter-strip resistance and capacitance, the bias resistance and the effectiveness of PTP structures as a function of bias voltage and fluence. It has been verified that the ATLAS12 sensors have high breakdown voltage well above the operational voltage which implies that different geometries of sensors do not influence their stability. The inter-strip isolation is a strong function of irradiation fluence, however the sensor performance is acceptable in the expected range for HL-LHC. New gated PTP structure exhibits low PTP onset voltage and sharp cut-off of effective resistance even at the highest tested radiation fluence. The inter-strip capacitance complies with the technical specification required before irradiation and no radiation-induced degradation was observed. A summary of ATLAS12 sensors tests is presented including a comparison of results from different irradiation sites. The measured characteristics are compared with the previous prototype of the sensor design, ATLAS07.

Nuclear instruments & methods in physics research / A 831, 221 - 228(2016). doi:10.1016/j.nima.2016.04.019, A proposal to fabricate large area strip sensors with integrated, or embedded, pitch adapters is presentedfor the End-cap part of the Inner Tracker in the ATLAS experiment. To implement the embedded pitchadapters, a second metal layer is used in the sensor fabrication, for signal routing to the ASICs. Sensorswith different embedded pitch adapters have been fabricated in order to optimize the design andtechnology. Inter-strip capacitance, noise, pick-up, cross-talk, signal efficiency, and fabrication yield havebeen taken into account in their design and fabrication. Inter-strip capacitance tests taking into accountall channel neighbors reveal the important differences between the various designs considered. Thesetests have been correlated with noisefigures obtained in full assembled modules, showing that the testsperformed on the bare sensors are a valid tool to estimate thefinal noise in the full module. The fullmodules have been subjected to test beam experiments in order to evaluate the incidence of cross-talk,pick-up, and signal loss. The detailed analysis shows no indication of cross-talk or pick-up as no addi-tional hits can be observed in any channel not being hit by the beam above 170 mV threshold, and thesignal in those channels is always below 1% of the signal recorded in the channel being hit, above 100 mVthreshold. First results on irradiated mini-sensors with embedded pitch adapters do not show anychange in the interstrip capacitance measurements with only thefirst neighbors connected., Published by North-Holland Publ. Co., Amsterdam

Nuclear instruments & methods in physics research / A 831, 167 - 173(2016). doi:10.1016/j.nima.2016.03.042, The “ATLAS ITk Strip Sensor Collaboration” R&D group has developed a second iteration of single-sided n+-in-p type micro-strip sensors for use in the tracker upgrade of the ATLAS experiment at the High-Luminosity (HL) LHC. The full size sensors measure approximately 97×97 mm$^2$ and are designed for tolerance against the 1.1×10$^{15}$n$_{eq}$/cm$^2$ fluence expected at the HL-LHC. Each sensor has 4 columns of 1280 individual 23.9mm long channels, arranged at 74.5μm pitch. Four batches comprising 120 sensors produced by Hamamatsu Photonics were evaluated for their mechanical, and electrical bulk and strip characteristics. Optical microscopy measurements were performed to obtain the sensor surface profile. Leakage current and bulk capacitance properties were measured for each individual sensor. For sample strips across the sensor batches, the inter-strip capacitance and resistance as well as properties of the punch-through protection structure were measured. A multi-channel probecard was used to measure leakage current, coupling capacitance and bias resistance for each individual channel of 100 sensors in three batches. The compiled results for 120 unirradiated sensors are presented in this paper, including summary results for almost 500,000 strips probed. Results on the reverse bias voltage dependence of various parameters and frequency dependence of tested capacitances are included for validation of the experimental methods used. Comparing results with specified values, almost all sensors fall well within specification., Published by North-Holland Publ. Co., Amsterdam

The ATLAS collaboration R&D group “Development of n-in-p Silicon Sensors for very high radiation environment” has developed single-sided p-type 9.75 cm×9.75 cm sensors with an n-type readout strips having radiation tolerance against the 1015 1-MeV neutron equivalent (neq)/cm2 fluence expected in the Super Large Hadron Collider. The compiled results of an evaluation of the bulk and strip parameter characteristics of 19 new non-irradiated sensors manufactured by Hamamatsu Photonics are presented in this paper. It was verified in detail that the sensors comply with the technical specifications required before irradiation. The reverse bias voltage dependence of various parameters, frequency dependence of tested capacitances, and strip scans of more than 23,000 strips as a test of parameter uniformity and strip quality over the whole sensor area have been carried out at Stony Brook University, Cambridge University, University of Geneva, and Academy of Sciences of CR and Charles University in Prague. No openings, shorts, or pinholes were observed on all tested strips, confirming the high quality of sensors made by Hamamatsu Photonics.

The ATLAS experiment is preparing for the planned luminosity upgrade of the LHC (the super-luminous LHC or sLHC) with a programme of development for tracking able to withstand an order of greater magnitude radiation fluence and much greater hit occupancy rates than the current detector. This has led to the concept of an all-silicon tracker with an enhanced performance pixel-based inner region and short-strips for much of the higher radii. Both sub-systems employ many common technologies, including the proposed "stave" concept for integrated cooling and support. For the short-strip region, use of this integrated stave concept requires single-sided modules mounted on either side of a thin central lightweight support.Each sensor is divided into four rows of 23.82 mm length strips; within each row, there are 1280 strips of 74.5μm pitch. Well over a hundred prototype sensors are being delivered by Hamamatsu Photonics (HPK) to Japan, Europe and the US.We present results of the first 20 chip ABCN25 ASIC hybrids for these sensors, results of the first prototype 5120 strip module built with 40 ABCN25 read-out ASICs, and the status of the hybrids and modules being developed for the ATLAS tracker upgrade stave programme.

We are developing n+-in-p, p-bulk and n-readout, microstrip sensors as a non-inverting radiation hard silicon detector for the ATLAS Tracker Upgrade at the super LHC experiment. The surface radiation damages of the sensors fabricated by Hamamatsu Photonics are characterized on the interstrip capacitance, interstrip resistance and punch-through protection evolution. The detector should provide acceptable strip isolation, exceeding the input impedance of the signal readout chip ∼1 kΩ, after the integrated luminosity of 6 ab−1, which is twice the luminosity goal.

We are developing n+-in-p, p-bulk and n-readout, microstrip sensors, fabricated by Hamamatsu Photonics, as a non-inverting radiation hard silicon detector for the ATLAS tracker upgrade at the super-LHC (sLHC) proposed facility. The bulk radiation damage after neutron and proton irradiations is characterized with the leakage current, charge collection and full depletion voltage. The detectors should provide acceptable signal, signal-to-noise ratio exceeding 15, after the integrated luminosity of 6000 fb−1, which is twice the sLHC integrated luminosity goal.

We have developed a novel and highly radiation-tolerant n-in-p silicon microstrip sensor for very high radiation environments such as in the Super Large Hadron Collider. The sensors are designed for a fluence of 1×1015 neq/cm2 and are fabricated from p-type, FZ, 6 in. (150 mm) wafers onto which we lay out a single 9.75 cm×9.75 cm large-area sensor and several 1 cm×1 cm miniature sensors with various n-strip isolation structures. By evaluating the sensors both pre- and post-irradiation by protons and neutrons, we find that the full depletion voltage evolves to approximately 800 V and that the n-strip isolation depends on the p+ concentration. In addition, we characterize the interstrip resistance, interstrip capacitance and the punch-through-protection (PTP) voltage. The first fabrication batch allowed us to identify the weak spots in the PTP and the stereo strip layouts. By understanding the source of the weakness, the mask was modified accordingly. After modification, the follow-up fabrication batches and the latest fabrication of about 30 main sensors and associated miniature sensors have shown good performance, with no sign of microdischarge up to 1000 V.

The CALICE collaboration is undertaking a major R&D programme into calorimetry for the International Linear Collider (ILC). The programme includes the development and test of electromagnetic calorimeter (ECAL) prototypes. The ECAL is built by interleaving Tungsten layers with very thin, multi layer PCBs integrating the Silicon sensors, the Very Front End chips, and electrical infrastructure. These instrumentation slabs are assembled from multiple PCB panels, requiring reliable, high quality panel interconnects. In this paper, the focus is on two aspects of the distribution of high-speed signals towards many chips across multiple panels. Firstly, the distribution of high-speed (clock) signals from a single source towards many chips over large distances is discussed, followed by a presentation on the application of various interconnect technologies for non-invasive joining of very thin multi layer PCBs. The proposed interconnects are studied, and simulation and measurement results on signal transmission properties are presented. Results of studies using a realistic, full-length slab prototype containing FPGAs emulating VFE chips are discussed. The paper is concluded with recommendations regarding the panel interconnect properties, and the distribution of high speed signals towards many chips over metre-scale distances. The work described above is part of the UK programme to develop a data acquisition system for CALICE.

The outer tracker detector of the LHCb experiment is a gas filled detector based on straw tube technology. It comprises three stations each consisting of multiple layers of wires with both vertical orientation and /spl plusmn/5/spl deg/ stereo angles. The stations are designed to be built of modules which are mechanically stable, gas tight and capable of stand-alone operation. This paper describes the design and mass production procedures of outer tracker modules and discusses the quality assurance programme. Test results on the first modules produced are included.

A data acquisition (DAQ) system has been developed which will read out and control calorimeters serving as prototype systems for a future detector at an electron-positron linear collider. This is a modular, flexible and scalable DAQ system in which the hardware and signals are standards-based, using FPGAs and serial links. The idea of a backplaneless system was also pursued with a commercial development board housed in a PC and a chain of concentrator cards between it and the detector forming the basis of the system. As well as describing the concept and performance of the system, its merits and disadvantages are discussed., 12 pages, 6 figures, accepted by JINST. Version updated accounting for comments from journal referees