Radiation Testing of an SAR ADC for Use

Radiation Testing of an SAR ADC for Use in Quench Detection Systems for the Hi. Lumi LHC J. Spasic, R. Denz, J. Kopal, and J. Steckert RADECS 2017

Introduction • • • High Luminosity Large Hadron Collider (Hi. Lumi-LHC) Planned upgrade to increase luminosity Important part of the upgrade – new high-field superconducting magnets New magnets New quench detection systems (QDS) to ensure fast and reliable quench detection QDS requires accurate and fast signal measurement using suitable analog-to-digital converter (ADC) ADC has to operate properly in the presence of radiation levels found in the LHC – typical radiation dose of 1 Gy/year is expected To assess ADC behavior when exposed to radiation, an irradiation testing campaign has been conducted 3/9/2021 RADECS 2017 3

New QDS – universal QDS • • Versatile system, software-defined “One solution fits most” Isolated analog input channel 1 Controls interface Isolated analog input channel 2 Input protection Isolated analog input channel 16 3/9/2021 Buffer & gain FPGA ADC driver ADC Interlocks Memory RADECS 2017 4

Our experience with ADCs ADC SAR Sigma-delta General characteristics • Low power consumption • Simple structure • No latency • Higher power consumption • Large filters and modulator • Larger latency Used so far in QDS • MAX 1162 200 k. Sps 16 -bit • MAX 11049 250 k. Sps 16 -bit • ADu. C 834 100 Sps 16, 24 -bit • ADS 1281 4 k. Sps 24 -bit Performance in radiation • Low rate of SEEs up to 200 Gy • Good tolerance to TID (up breakdown at 400 Gy - 500 Gy to 650 Gy) BUT frequent • Only one type of SEU – single SEEs sample spikes • SEUs in 3 different stages • No SEFIs of the ADC (single, multiple sample, gain/offset errors) • SEFIs in the modulator stage (ADC stops) • Our choice: LTC 2378 -20 1 MSps 20 -bit SAR ADC combines speed with resolution 3/9/2021 RADECS 2017 5

Test Setup • Irradiation testing campaign carried out at the Paul Scherrer Institute (PSI) Proton Irradiation Facility (PIF) in Switzerland • • • 200 Me. V proton beam Radiation dose up to 1 k. Gy, dose rate 0. 1 Gy/s, flux 2*108 p/cm 2/s Testing ADC performance and single event errors 3/9/2021 RADECS 2017 6

Test Setup – Baseboard • • • FPGA for controlling ADCs and for data transmission Flash-based Microsemi Pro. Asic 3 FPGA used for increased tolerance to radiation FPGA protected with triple modular redundancy to prevent radiation induced errors in SRAM Place for DUT 3/9/2021 RADECS 2017 7

Test Setup – DUT • • 4 ADCs tested at once: LTC 2378 -20 sampling at 9. 76 k. Hz ADCs tested for noise and offset performance and single event errors (Single Event Upsets, Single Event Functional Interrupts and Single Event Latch-Ups) Beam focusing area with 4 tested ADCs bottom-top: ADC 1 -4 3/9/2021 RADECS 2017 8

Test Results • Tests performed on 2 DUTs and baseboards up to 1 k. Gy dose 3/9/2021 RADECS 2017 9

Test Results – DUT 1 • Power supply • No SELs 3/9/2021 RADECS 2017 10

Test Results – DUT 1 • Noise and offset • Within specifications up to 500 Gy 3/9/2021 RADECS 2017 11

Test Results • Different dose profile for DUT 2 3/9/2021 RADECS 2017 12

Test Results – DUT 2 • Power supply • No SELs 3/9/2021 RADECS 2017 13

Test Results – DUT 2 • Noise and offset • Within specifications up to 500 Gy 3/9/2021 RADECS 2017 14

Conclusions • • • For use within QDS for HL-LHC, LTC 2378 -20 ADC was successfully tested under elevated radiation levels Test results showed no signs of decrease in performance under expected radiation levels Future work – assessing ADC performance at higher sampling frequencies 3/9/2021 RADECS 2017 15

Thank you for your attention! 3/9/2021 Jelena Spasić – Personal Presentation 16