SPIDER neutron diagnostic: Overall System Description

This document presents advances in the design of the CNESM neutron diagnostic for SPIDER. It is submitted as Progress Report P1.1 of subtask T3.5 of the F4E contract F4E-RFX-PMS_A-WP-2017. This is an update of the previous version, RFX_SPIDER_TN_169_r5, submitted as deliverable of the F4E contract F4E-RFX-PMS_A-WP-2016. This report describes the design of the CNESM diagnostic for SPIDER. The active part of the diagnostic is constituted by the nGEM detector whose design is fully described here together with all the services that are needed for its operation (gas system, HV system and DAQ system). The test of nGEM detector prototypes are described in report RFX_SPIDER_TN_170_r6. The report comprises the design of the detector box together with its integration with the beam dump and acceptance criteria (mainly concerning vacuum sealing), its installation/removal procedures and all the related services. The system design progressed in 2017 in the following areas: - Completion of the CNESM engineering design related to: - definition and production of the final patch panel for signals and threshold settings, - Installation of the nGEM detector and related facilities in the detector box - - - Purchase of a fast plastic scintillator in order to perform a time resolved neutron yield measurement in SPIDER as a benchmark for the measurement performed by the nGEM The main changes made in this version of the Report can be found in paragraph 8, 9 and 10. Risk management was also addressed. No major cause of concern could be foreseen.