Development of silicon detectors for Beam Loss Monitoring at HL-LHC

Abstract

Silicon detectors were proposed as novel Beam Loss Monitors (BLM) for the control of the radiation environment in the vicinity of the superconductive magnets of the High-Luminosity Large Hadron Collider. The present work is aimed at enhancing the BLM sensitivity and therefore the capability of triggering the beam abort system before a critical radiation load hits the superconductive coils. We report here the results of three in situ irradiation tests of Si detectors carried out at the CERN PS at 1.9–4.2 K. The main experimental result is that all silicon detectors survived irradiation up to 1.22× 1016 p/cm2. The third test, focused on the detailed characterization of the detectors with standard (300 μm) and reduced (100 μm) thicknesses, showed only a marginal difference in the sensitivity of thinned detectors in the entire fluence range and a smaller rate of signal degradation that promotes their use as BLMs. The irradiation campaigns produced new information on radiation damage and carrier transport in Si detectors irradiated at the temperatures of 1.9–4.2 K. The results were encouraging and permitted to initiate the production of the first BLM prototype modules which were installed at the end of the vessel containing the superconductive coil of a LHC magnet immersed in superfluid helium to be able to test the silicon detectors in real operational conditions.

Signal amplification in multistage charge collection process in Si detectors in situ irradiated at superfluid helium temperature

“…whose contribution to the collected charge in the second stage can compensate a decrease in 𝜏 h tr with fluence. This feature is illustrated in figure 12 by the 𝑄 c on 𝐹 𝑝 dependences for Si detectors with the thickness of 300 and 100 μm irradiated in situ at 𝑇 = 4.3 K. In the figure, the dependences are recalculated from the experimental data in [16] by normalization of the charge collected per mip; the latter was determined by integrating the individual current responses from a single spill recorded over the spill duration of 400 ms and averaging the values measured for two spill cycles. The data were recorded starting from a lower fluence of 3 × 10 13 p/cm 2 used as reference point in figure 12, which allowed observing the curves with a rise in 𝑄 c .…”

О Формировании Траектории Оси Лазерного Излучения В Дифференциальной Кювете Андерсона

“…Это связано с различными причинами, основными из которых являются ухудшение экологии, нарушение условий хранения и транспортировки конденсированных сред вследствие сокращения издержек, а также снижение качества при производстве самих сред и т. д. [5][6][7][8]. Поэтому перед использованием конденсированных сред, особенно при проведении различных экспериментов, их необходимо оперативно проверять, чтобы обеспечить достоверность получаемых результатов.…”

On the Formation of the Trajectory of Propagation of Laser Radiation in the Anderson Differential Cell

“…It is connected to different causes, the main of which are environmental degradation, failure to meet conditions of storage and transportation of condensed media due to cost saving, as well as quality impairment in the production of media themselves, etc . [5][6][7][8].…”