LPG sensor technology for environmental monitoring: from the laboratory to the detector

by Lorenzo Scherino (Universita del Sannio (IT))

Wednesday 11 May 2022, 09:30 → 11:00 Europe/Zurich

32/1-A24 (CERN)

For the Inner Tracker (ITk) detector of the ATLAS experiment at CERN the environmental monitoring is essential for optimal operative conditions. A constant relative humidity monitoring is required in fifty different points inside the ITk detector, where the dew point is lower than -60°C.

In this context, Fiber Optic Sensor (FOS) technology based on Long Period Grating (LPG) and Fiber Bragg Grating (FBG) have been combined to provide a unique sensing device. The FBG sensors are a consolidated technology that can provide relative humidity (RH) and temperature monitoring over a wide range. However, with intrinsic sensitivity of 1% RH and accuracy of 2% RH, they fail to detect relative humidity with satisfactory precision when it goes below 10%. In this range, the very high sensitivity of LPG sensors to relative humidity enables its accurate measurement. This device must be installed in an ad-hoc package that guarantees its protection against damages while leaving its response and performance unchanged. Moreover, a customized multiplexing system has been developed to continuously and simultaneously monitor the fifty measurement points inside the ITk detector with a single optical fibre interrogator.

The seminar will focus on the engineering aspects that led to the development of the final device for environmental monitoring in the ATLAS ITk detector. In particular, an exhaustive analysis and discussion about the irradiation response, the package development and the multiplexing system will be performed.

LPG sensor technology for environmental monitoring.pdf

LPG sensor technology for environmental monitoring.pptx