A state of the art leakage current compensating femtoampere current to frequency converter for radiation monitoring

• Evgenia Voulgari (CERN)

Room: 222/R-001 Abstract: CERN has a legal obligation to comply with the legislation in matters of radiation protection. According to the existing detectors, the current output varies from 2 fA up to the microampere range. A state of the art microelectronic integrated wide dynamic range front-end was designed for radiation monitoring. The architecture of an asynchronous current to frequency converter is fully exploited since for lower radiation and equivalently for lower input current the measurement time can be increased. By active leakage current compensation, the circuit is able to measure current as low as 1 fA. The addition of a second reference charge injection circuit gives the possibility to extend the upper measurement range up to the microamperes by keeping a constant acquisition time. The Utopia (Ultra-low picoammeter) 2 ASIC has been fully characterized for its low current performance at the Swiss Federal Institute of Metrology (METAS). The chip is able to digitize currents over more than 9 decades, from 1 fA up to 5 μA. The guidelines set for the design of the ultra-low leakage current converter can be used in any system that targets femtoampere current measurements.

Some significant experiences of HSE unit support to structural safety problems at CERN

• Marco Andreini (CERN)

Room: 222/R-001 Abstract: Structural safety is a transversal domain, which interests mainly Civil and Mechanical Engineering. CERN and, in general, particle physics laboratories are faced to plenty of challenges in assuring structural safety with respect to industrial and environmental loads. In particular, the design and constructions of new facilities, installations and infrastructures, and the verification and retrofitting of the existing ones require a deep and constant attention to the assessment of the mechanical resistance of the loadbearing elements. Structural design support, validation, accident follow-up and research are the activities currently carried out within the HSE/SEE group. Some significant case studies in all of these activities are presented. In particular, the propping intervention of the false floors at the SPS surface buildings during last YETS and EYETS and the POPS explosion follow-up are shown. Moreover, the definition of the pressure increase due to the seismic acceleration in the ProtoDUNE cryostats are described. Finally, the validation process of the GBAR linac supporting structure and the preliminary results of an on-going research on the stability of the shielding block constructions are presented.

HL-LHC buildings : acoustical modelling

• Quentin Goestchel

Room: 222/R-001 Abstract: The HL-LHC project involves the construction of new cooling towers, transformers and noisy buildings at LHC points 1 and 5. This novelty has already been modelled but without taking into account the existing elements. In order to predict whether the global CERN noise level will be compliant with legal requirement, acoustic modelling of the overall situation is necessary. The calculation method, the theory of sound transmission losses and the results will be explained.