Non-ionising energy loss of radiation produces point defects and defect clusters in silicon, which result in a significant degradation of sensor performance. In this contribution results from TSC (Thermally Stimulated Current) defect spectroscopy for silicon pad diodes irradiated by electrons to fluences of a few 10 14 cm −2 and energies between 3.5 and 27 MeV for isochronal annealing between 80 and 280 • C, are presented. A method based on SRH (Shockley-Read-Hall) statistics is introduced, which assumes that the ionisation energy of the defects in a cluster depends on the fraction of occupied traps. The difference of ionisation energy of an isolated point defect and a fully occupied cluster, ∆E a , is extracted from the TSC data.For the VO i (vacancy-oxygen interstitial) defect ∆E a = 0 is found, which confirms that it is a point defect, and validates the method for point defects. For clusters made of deep acceptors the ∆E a values for different defects are determined after annealing at 80 • C as a function of electron energy, and for the irradiation with 15 MeV electrons as a function of annealing temperature. For the irradiation with 3.5 MeV electrons the value ∆E a = 0 is found, whereas for the electron energies of 6 to 27 MeV ∆E a > 0. This agrees with the expected threshold of about 5 MeV for cluster formation by electrons. The ∆E a values determined as a function of annealing temperature show that the annealing rate is different for different defects. A naive diffusion model is used to estimate the temperature dependencies of the diffusion of the defects in the clusters.

The proton linac of the European Spallation Source, under construction in Lund, Sweden, had beam commissioning of its ion source (IS) and the following low energy beam transport (LEBT) at their final locations from September 2018 to July 2019. This was first of several beam commissioning stages for the linac of ESS, towards the start of the user program in 2023. This paper presents highlights of characterizations of the IS and LEBT from the aforementioned beam commissioning period, including behavioral change of the IS against its parameters, error source identifications of the beam trajectory in the LEBT, and preliminary characterization of the LEBT output beam against solenoid strengths in LEBT. K: Ion sources (positive ions, negative ions, electron cyclotron resonance (ECR), electron beam (EBIS)); Beam-line instrumentation (beam position and profile monitors; beam-intensity monitors; bunch length monitors); Beam dynamics 1Corresponding author.

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Irradiation experiments on silicon sensors are used to mimic the radiation environment at collider experiments with the aim to forecast the change of the electrical properties of a detector with irradiation. Measurements on irradiated sensors are invaluable in choosing a material well suited for a silicon tracking detector. This is especially true for the upgraded detectors to be used in the high-luminosity phase of the LHC (HL-LHC), where silicon sensors as currently used would suffer severe loss in signal from irradiation with charged and neutral hadrons. The CMS Tracker Collaboration has initiated irradiation studies with protons with energies ranging from 23 MeV to 23 GeV. They are often used instead of charged hadrons, their radiation induced damage to the silicon being rather similar. However, in oxygen rich silicon, NIEL violation concerning the full depletion voltage has been observed. In this paper results from investigations on bulk defects compared to the change of the electrical properties of silicon pad-sensors will be summarized after irradiations with 23 MeV and 23 GeV protons. Differences in the generation of specific defects in the bulk were observed depending on the proton energy. A possible impact of such defects on the electrical properties will be evaluated. Abstract-Irradiation experiments on silicon sensors are used to mimic the radiation environment at collider experiments with the aim to forecast the change of the electrical properties of a detector with irradiation. Measurements on irradiated sensors are invaluable in choosing a material well suited for a silicon tracking detector. This is especially true for the upgraded detectors to be used in the high-luminosity phase of the LHC (HL-LHC), where silicon sensors as currently used would suffer severe loss in signal from irradiation with charged and neutral hadrons. The CMS Tracker Collaboration has initiated irradiation studies with protons with energies ranging from 23 MeV to 23 GeV. They are often used instead of charged hadrons, their radiation induced damage to the silicon being rather similar. However, in oxygen rich silicon, NIEL violation concerning the full depletion voltage has been observed. In this paper results from investigations on bulk defects compared to the change of the electrical properties of silicon pad-sensors will be summarized after irradiations with 23 MeV and 23 GeV protons. Differences in the generation of specific defects in the bulk were observed depending on the proton energy. A possible impact of such defects on the electrical properties will be evaluated.

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