ITk radiation monitoring I. Mandić et al. Jožef Stefan Institute, Ljubljana, Slovenia

1. ITk radiation monitoring I. Mandić et al. Jožef Stefan Institute, Ljubljana, Slovenia SPR ITK common environmental monitoring and interlocking - radiation monitoring, 24th September 2019

2. Introduction: • goal of radiation monitoring system is measurement of displacement damage in Si caused by energetic • hadrons (NIEL - 1 MeV neqfluence) and TID at several locations in the detector • to cross check radiation background simulations • online (remote) readout of sensors: •  necessary in the ITkbecause there is no access to replace passive dosimeters •  frequent measurements, up to date information about doses and fluences, better accuracy, • better control of annealingeffects… • dose monitoring more important at start of operation: •  early comparison with radiation background simulations •  doses proportional to integrated luminosity  measure dose/integrated_luminosity • accuracy less important at high doses towards the end of operation SPR ITK common environmental monitoring and interlocking - radiation monitoring, 24th September 2019

3. Introduction • ITk radiation monitor system: • measure TID from ~ 1 kGy to ~100 kGy • measure Фeqfrom ~ 1013 to ~ 1015 n/cm2 • precision about ~20% • build a similar system to the one now running in ATLAS ID Results of radiation monitoring system in ATLAS ID for Run 2: SPR ITK common environmental monitoring and interlocking - radiation monitoring, 24th September 2019

4. Sensors • NIEL: • OSRAM BPW34 diodes • measure forward bias at 1 mA forward current • can be used up to1e15 n/cm2 •  needs sufficiently high bias voltages • F. Ravotti et al. , IEEE TNS, VOL. 55, (2008), p 2133 • M.R. Hoeferkamp, et al., NIMA 890 (2018) 108-111, https://doi.org/10.1016/j.nima.2018.02.070 • P. Palni, et al., NIMA 735 (2014) 213–217, • http://dx.doi.org/10.1016/j.nima.2013.09.037 M.R. Hoeferkamp et al. NIMA 890 (2018) 108-111 SPR ITK common environmental monitoring and interlocking - radiation monitoring, 24th September 2019

5. Sensors • TID: • RadFET(p-MOS transistors) • measure gate voltage at given drain current • need thin oxide RadFETs for high doses (above few kGy) •  not many manufacturers •  a set of devices (REM, oxide thickness 130 nm) • used in ATLAS ID available from the PS-IRRAD team •  new manufacturer: AbantIzzetBaysal University, Bolu, Turkey • (Center of Nuclear Radiation Detector Research and Application (NURDAM)) • Promising results at high doses with 65 nm oxide • thickness devices • Selection of sensors: max. response at highest doses, • minimum fading after hadron irradiation •  irradiation studies are going on NurFET See: A.H. Siedle, F. Ravotti, M.Glaser, The Dosimetric Performance of RADFETs in Radiation Test Beams 2007 IEEE Radiation Effects Data Workshop, https://doi.org/10.1109/REDW.2007.4342539 SPR ITK common environmental monitoring and interlocking - radiation monitoring, 24th September 2019

6. Locations • max. fluence ~ 1e15 neq/cm2 • max. TID~ 1e5 Gy •  doses/fluences are proportional to integrated luminosity sensitivity up to maximal doses/fluences not critical, monitors can be placed also in locations with somewhat higher doses SPR ITK common environmental monitoring and interlocking - radiation monitoring, 24th September 2019

7. Locations fixed on outer side of Outer Cylinder • fixed on the blades of disk 1 or disk 2 • inside tracking volume, connection goes • through the enclosure strip EC service volume, outer side of the bulkhead pixel service volume outside of the enclosure SPR ITK common environmental monitoring and interlocking - radiation monitoring, 24th September 2019

8. Radiation Monitor Sensor Board (RMSB) • example from ATLAS ID shown on photos Back side ( heater for temp stabilization) Sensor side Pigtail cable • Ceramic (Al2O3) • front side: sensors • back side: resistive layer • Very similar design for ITk: • 3 RadFETs (TID) • temperature sensor (10 kOhmNTC) • 3 BPW34 diodes (NIEL) PCB ~ 2.2 cm SPR ITK common environmental monitoring and interlocking - radiation monitoring, 24th September 2019

9. Radiation Monitor Sensor Board (RMSB) • hybrid fixed inside PEEK box, 3 cm x 3 cm, 0.8 cm thick, • flat cable soldered and clamped to the PCB • cable connector, 1.27 mm pitch (ERNI or 3M SN: 45110-000000) Sensor box 3 cm x 3 cm 8 mm thick • Photo of the connector on the mockup : • ERNI, 1.27 mm pitch, flat cable, 30 AWG wires • this is an example of possible connector Mockup with ~ 1 m pigtail • Connections: • monitors inside tracking volume (8 locations, 4 per side on strip EC) will be connected via PP1, • 2 RMSB in contiguous quadrants will connect to one connector at high radius in one EC tray •  connection of remaining RMSB (not entering the enclosure) to type II cables needs to be defined SPR ITK common environmental monitoring and interlocking - radiation monitoring, 24th September 2019

10. Readout • measure voltage over radiation sensor at given current • current pulses ~0.1 mA (RADFET), ~ 1 mA (diode), < 1 s long, voltage from ~ 0 V to ~ 100 V after highest doses •  use voltage divider to adapt to ADC dynamic range, may be adjusted during operation to follow • large increase of voltage after exposure to large doses/fluneces •  ADC with 12 bit resolution OK • read few times per hour •  when not read out no bias (sensor contacts shorted) • temperature stabilization: DC current to heat ceramic hybrid (~2 W for ΔT = 60°C  50 mA at 40 V) • 6 radiation sensors (3 NIEL, 3 TID)+ 1 temperature sensor + return wire + temperature stabilization pair •  10 wires per RMSB • readout circuitry (current sources, ADCs …) in USA15 SPR ITK common environmental monitoring and interlocking - radiation monitoring, 24th September 2019

11. Readout Read sensors one by one, few times per hour • readout based on ELMB2  same functionality as ELMB, communication with DCS via ELMB2 • similar radiation monitor readout system running now in the ID adapt firmware for ELMB2 •  build new current source unit controlled by ELMB2: • a) chose DAC compatible with ELMB2 firmware • b) output up to 100 V •  readout system must meet grounding and shielding requirements •  floating power supply referenced at the Faraday cage • design of current sources and monitoring circuits will follow the solutions described in: • ATL-IP-ES-0106 The Supply and Control system for the Opto Link of the ATLAS pixel detector SPR ITK common environmental monitoring and interlocking - radiation monitoring, 24th September 2019

12. Schedule • monitors in EC volume (z ~ 160 cm, r ~ 60 cm, 8 locations) connected via PP1 •  cables/connectors up to PP1 should be ready for installation in the beginning of 2021 •  sensor boards with pigtail cable will be installed in ~ 2023 • other locations: •  installation in 2024 or 2025 •  not connected via PP1, connections to type II services to be defined • readout •  components in USA15 •  readout based on ELMB2 •  integrated in DCS by the start of HL-LHC SPR ITK common environmental monitoring and interlocking - radiation monitoring, 24th September 2019

13. Summary • radiation monitoring system for ATLAS ITk • measure NIEL (1 MeV neqfluence) and TID in Si at several locations in the detector to cross check radiation • background simulations • similar system as currently running in ATLAS ID • sensor candidates with required properties found, selection of RadFET manufacturer has to be made • locations defined • readout system will be based on ELMB2 • sensor boards and readout will be designed and manufactured by Jožef Stefan Institute SPR ITK common environmental monitoring and interlocking - radiation monitoring, 24th September 2019