Cobalt-60 gamma irradiation of silicon test structures for high-luminosity collider experiments

During the era of the High Luminosity LHC (HL-LHC) the devices in the experiments will be subjected to increased radiation levels with fluxes of neutrons and charged hadrons in the inner detectors reaching up to approximately $\mathrm{2.3\times10^{16}\:n_{eq}/cm^2}$ and total ionization doses up to around 1.2 Grad. A systematic program of radiation tests with neutrons and charged hadrons is being carried out by the CMS and ATLAS Collaborations in order to cope with the higher luminosity of HL-LHC and the associated increase in the pile-up events and radiation fluxes. In this work, results from a complementary radiation study with $^{60}$Co-\upgamma photons are presented. The doses are equivalent to those that the outer layers of the silicon tracker systems of the two experiments will be subjected to. The devices in this study are p-type diodes and MOS capacitors

Gas Sensitivity Amplification of Interdigitated Chemocapacitors Through Etching

In polymer coated planar Inter Digitated Electrodes (IDEs), the gas sensing sensitivity is much lower than the sensitivity of parallel plate capacitors. Here, we introduce a simple patterning step for the modification of the geometry of the dielectric substrate of the planar IDEs, and increase of the contribution of the sensitive layer to the output signal. The proposed methodology is investigated through simulation and verified by experimental data. Polymer coated IDEs with different dimensions of spatial wavelength were studied experimentally upon exposure to analytes of varying polarity. The sensing performance of the fabricated structures compare very well with theoretically estimated values obtained through finite element simulations. The maximum performance gain is also calculated by simulation demonstrating the potential of the technology

Strategies and performance of the CMS silicon tracker alignment during LHC Run 2

The strategies for and the performance of the CMS silicon tracking system alignment during the 2015–2018 data-taking period of the LHC are described. The alignment procedures during and after data taking are explained. Alignment scenarios are also derived for use in the simulation of the detector response. Systematic effects, related to intrinsic symmetries of the alignment task or to external constraints, are discussed and illustrated for different scenarios