Evaluation and testing of advanced low-voltage power supplies

A distinguishing feature of the LHC detectors is the enormous number of front end electronics channels in all the sub-detectors. Low voltage power supply systems in the range of multi kilowatts are required to bias such electronics. These power supplies will be located in the cavern close to the detector where stray magnetic field and radiation are present. The main advantage of this topology is the reduction of the length cable needed to carry power to the electronics. This paper describes results on electrical and environmental tests performed on sample equipment. Descriptions of the objects and methods of tests are given

The ABC130 barrel module prototyping programme for the ATLAS strip tracker

For the Phase-II Upgrade of the ATLAS Detector, its Inner Detector, consisting of silicon pixel, silicon strip and transition radiation sub-detectors, will be replaced with an all new 100 % silicon tracker, composed of a pixel tracker at inner radii and a strip tracker at outer radii. The future ATLAS strip tracker will include 11,000 silicon sensor modules in the central region (barrel) and 7,000 modules in the forward region (end-caps), which are foreseen to be constructed over a period of 3.5 years. The construction of each module consists of a series of assembly and quality control steps, which were engineered to be identical for all production sites. In order to develop the tooling and procedures for assembly and testing of these modules, two series of major prototyping programs were conducted: an early program using readout chips designed using a 250 nm fabrication process (ABCN-25) and a subsequent program using a follow-up chip set made using 130 nm processing (ABC130 and HCC130 chips). This second generation of readout chips was used for an extensive prototyping program that produced around 100 barrel-type modules and contributed significantly to the development of the final module layout. This paper gives an overview of the components used in ABC130 barrel modules, their assembly procedure and findings resulting from their tests.Comment: 82 pages, 66 figure

Test beam performance of a CBC3-based mini-module for the Phase-2 CMS Outer Tracker before and after neutron irradiation

The Large Hadron Collider (LHC) at CERN will undergo major upgrades to increase the instantaneous luminosity up to 5–7.5×10$^{34}$ cm$^{-2}$s$^{-1}$. This High Luminosity upgrade of the LHC (HL-LHC) will deliver a total of 3000–4000 fb-1 of proton-proton collisions at a center-of-mass energy of 13–14 TeV. To cope with these challenging environmental conditions, the strip tracker of the CMS experiment will be upgraded using modules with two closely-spaced silicon sensors to provide information to include tracking in the Level-1 trigger selection. This paper describes the performance, in a test beam experiment, of the first prototype module based on the final version of the CMS Binary Chip front-end ASIC before and after the module was irradiated with neutrons. Results demonstrate that the prototype module satisfies the requirements, providing efficient tracking information, after being irradiated with a total fluence comparable to the one expected through the lifetime of the experiment

Electrochemical transfer at p-type silicon(1 1 1)-alkyl monolayer hybrid electrodes in acetonitrile medium

International audienc

Reliability test results of the interconnect structures of the front-end hybrids for the CMS Phase-2 Tracker Upgrade

High Density Interconnect (HDI) hybrids are being developed for the CMS Tracker Phase Two Upgrade for the HL-LHC. These hybrids are carbon fibre reinforced flexible circuits with flip-chips, passives and connectors. Their operational lifetime is determined by the reliability of the solder joints of the surface mount components (flip-chips, passives, connectors) and the copper traces and vias in the hybrid substrate. Specific test coupons were exposed to accelerated thermal stress cycles, aiming to test the reliability of the solder joints, vias and traces. Results from different suppliers and technologies will be evaluated and compared

Anthracene and anthracene:C60 adduct-terminated monolayers convalently bound to hydrogen-terminated silicon surfaces

International audienceAnthracene monolayers covalently bound to hydrogen-terminated n-type Si(100) surfaces have been prepared from the attachment of an amine-substituted anthracene derivative to a preassembled acid-terminated alkyl monolayer using carbodiimide coupling. The anthracene headgroups were then used as anchoring sites for C60 following [4 + 2] Diels-Alder cycloaddition. After cycloaddition of C60 on the anthracene layer, the surface roughness determined by atomic force microscopy increased from 3.0 ± 0.7 to 5.0 ± 1.0 Å and the morphology showed uniformly distributed globular features a few nanometers high. Cyclic voltammograms of the anthracene-modified monolayer in the dark were characterized by an ill-defined reversible system at E°′ = −2.05 V vs saturated calomel electrode (SCE), which compares well with the value determined for the anthracene derivative in solution on a platinum electrode. Furthermore, the surface coverage of attached anthracene units was estimated to be (4.6 ± 0.3) × 10-10 mol cm-2, which is consistent with a densely packed monolayer. In contrast, the voltammogram of the C60-modified monolayer did not show multiple reversible one-electron transfers characteristic of the anthracene:C60 adduct. Instead, one irreversible cathodic peak at −1.50 V followed by a reversible system at −2.15 V was observed. These electrochemical differences between surface-confined and dissolved species are assigned to reduced charge transfer kinetics between the underlying semiconductor and bound C60 within a certain potential range. This hypothesis is consistent with the flat band potential Efb value of −0.80 ± 0.05 V vs SCE, determined from capacitance measurements. Moreover, scanning electrochemical microscopy (SECM) measurements in feedback mode provided clear evidence for the electroactive properties of bound C60. The SECM approach curves suggest that both the anthracene and anthracene:C60 layers displayed good conductivity, presumably by electron hopping between adjacent redox sites