This document presents advances in the validation of the principle of operation of nGEM detectors belonging to CNESM neutron diagnostic for SPIDER, as a first step towards the application of this diagnostic technique to MITICA, where it would be particularly useful to resolve the horizontal profile of the beam intensity. The report is submitted as part of Progress Report P1 of subtask T3.5 of the F4E contract F4E-RFX-PMS_AWP-2019. It is an update of the previous version of the report (RFX_SPIDER_TN_170_r7) delivered as Progress Report P1 of subtask T3.5 of the F4E contract F4E-RFX-PMS_A-WP-2018. Three reduced size prototypes (10x10 cm2 active area) were realized and tested: the first one was built in order to especially study the directionality property of nGEM detectors and to compare experimental results with MCNP simulation outcomes presented in T3.22-D2 of GRT-32. The second prototype was used to test digital data acquisition in a fast neutron beam. A third prototype was built in 2012 in order to test the final choice of construction material and method; it is a complete version, but for the smaller size, of the final detector that will be procured and installed in SPIDER. A full-size nGEM prototype for SPIDER was realized and tested in 2013. A second full-size prototype with enhanced performances was built and tested in 2014. The third full size prototype (whose design was further improved with respect to the second full size prototype) was built in 2016 and tested both using X-rays and neutrons during 2017. The new GEMINI chip has been fully designed and first prototyes have been realized and have been successfully characterized. A complete test of the GEMINI chips mounted on a Triple GEM detector was successfully performed in 2017. A total of 200 GEMINI chips were ordered in 2017and delivery was spread in 2017-2019. In 2018 other 1000 chips were ordered. A large number of GEMINI board (>100) was then produced and all of them were tested. Only about 2% of the boards were found not operational. During the period 2012-2019 several tests have underlined that nGEM detector is a suitable detector for the CNESM diagnostics. The specific properties tested and meeting the requirements for installation on SPIDER are: directionality, neutron detection efficiency, ?-ray rejection, linearity, unifromity of response over the active area space resolution, real time operation and time stability. In addition during this period it was proved that nGEM detector needs a modest flow of gas for its operation and that nGEM detector is insensitive to vibrational stresses. Finally a specific nGEM detector with 10x10 cm2 active area was built in 2018 to test the performance of doubled-density cards (named GEMINI-32D) on a real detector. This test gave very promising results in view of construction of nGEM detectors for MITICA. Further characterization in 2019 gave the possibility to calibrate the detector. In addition a detailed test on GEMINI radiation hardness proved that electronics is able to withstand an X-rays dose of 20 MRad. During 2020 the Radiation Hardness test will be completed by irradiating the chips with a very high dose of neutrons.
SPIDER neutron diagnostic: Prototype detector
Gorini G;Croci G;Muraro A;Rebai M;Perelli Cippo E;Gervasini G;Ghezzi F;Grosso G;Tardocchi M;
2019
Abstract
This document presents advances in the validation of the principle of operation of nGEM detectors belonging to CNESM neutron diagnostic for SPIDER, as a first step towards the application of this diagnostic technique to MITICA, where it would be particularly useful to resolve the horizontal profile of the beam intensity. The report is submitted as part of Progress Report P1 of subtask T3.5 of the F4E contract F4E-RFX-PMS_AWP-2019. It is an update of the previous version of the report (RFX_SPIDER_TN_170_r7) delivered as Progress Report P1 of subtask T3.5 of the F4E contract F4E-RFX-PMS_A-WP-2018. Three reduced size prototypes (10x10 cm2 active area) were realized and tested: the first one was built in order to especially study the directionality property of nGEM detectors and to compare experimental results with MCNP simulation outcomes presented in T3.22-D2 of GRT-32. The second prototype was used to test digital data acquisition in a fast neutron beam. A third prototype was built in 2012 in order to test the final choice of construction material and method; it is a complete version, but for the smaller size, of the final detector that will be procured and installed in SPIDER. A full-size nGEM prototype for SPIDER was realized and tested in 2013. A second full-size prototype with enhanced performances was built and tested in 2014. The third full size prototype (whose design was further improved with respect to the second full size prototype) was built in 2016 and tested both using X-rays and neutrons during 2017. The new GEMINI chip has been fully designed and first prototyes have been realized and have been successfully characterized. A complete test of the GEMINI chips mounted on a Triple GEM detector was successfully performed in 2017. A total of 200 GEMINI chips were ordered in 2017and delivery was spread in 2017-2019. In 2018 other 1000 chips were ordered. A large number of GEMINI board (>100) was then produced and all of them were tested. Only about 2% of the boards were found not operational. During the period 2012-2019 several tests have underlined that nGEM detector is a suitable detector for the CNESM diagnostics. The specific properties tested and meeting the requirements for installation on SPIDER are: directionality, neutron detection efficiency, ?-ray rejection, linearity, unifromity of response over the active area space resolution, real time operation and time stability. In addition during this period it was proved that nGEM detector needs a modest flow of gas for its operation and that nGEM detector is insensitive to vibrational stresses. Finally a specific nGEM detector with 10x10 cm2 active area was built in 2018 to test the performance of doubled-density cards (named GEMINI-32D) on a real detector. This test gave very promising results in view of construction of nGEM detectors for MITICA. Further characterization in 2019 gave the possibility to calibrate the detector. In addition a detailed test on GEMINI radiation hardness proved that electronics is able to withstand an X-rays dose of 20 MRad. During 2020 the Radiation Hardness test will be completed by irradiating the chips with a very high dose of neutrons.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
