KIT – University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association Institut für Experimentelle Kernphysik A comparative study of mixed irradiated silicon strip sensors 19 th RD50 Workshop – Florian Petry, Robert Eber T. Barvich, F. Bögelspacher, W. de Boer, A. Dierlamm, A. Kornmayer, Th. Müller, P. Steck

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Ingredients for the study Introduction Sensors Mixed irradiation scheme Annealing procedure ALiBaVa measuremets Results Charge collection Signal to noise ratio Leakage current Summary

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Sensor overview Sensor thickness: 300µm 5 sensors of each material MaterialTypePitch (µm)Manufacturer FZp-in-n50 (5)HIP FZn-in-p (p-spray)80 (5)Micron MCzp-in-n50 (5)HIP MCzn-in-p (p-spray)50(1), 80(3), 100(1)Micron

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Irradiation Mixed irradiation with protons and neutrons Chose 5 fluence mixtures corresponding to 5 different radii in the CMS Tracker after 3000fb -1 Irradiation with Protons in Karlsuhe ZAG: Cyclotron, 23MeV protons Irradiation with neutrons in Louvain-la-Neuve Neutron generation by shooting deuterons on Be target 1 step only neutron irradiation Radius (cm) Total fluence (n eq /cm 2 ) Neutron (n eq /cm 2 ) Proton (n eq /cm 2 ) 51.2* * * * * * * * * * * *10 14 >1204.0*

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Annealing Logarithmic annealing steps to observe short term (beneficial) annealing long term (reverse) annealing Temperature (°C) Duration (min) Annealing (d) M.Moll, phd thesis, Hamburg, 1999

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Parameterisation of charge collection Beneficial annealing Reverse annealing Stable damage

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Measurement Measurement Setup: 2 ALiBaVa stations in Karlsruhe 90 Sr source Signal Signal to noise ratio Leakage current Temperature: -20°C (-30°C) Voltage 0V – 1000V Cuts Seed: S/N > 5 Neighbour: S/N > 2 Total error on measurements: 2.5% Error on irradiated fluence > 10% The small ALiBaVa station HV Pre-cooling DB Scintillator Sensor

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Measurement Results Parameters T = -20°C V = 900V

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Charge collection P-type materials collect more charge than n-type materials FZ-n shows highest dependence on annealing time Large drop in charge collection after (reverse annealing) Only small dependence of charge collection on annealing time for other materials P N P N Increasing fluence

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Charge collection 1.8*10 15 n eq /cm 2 FZ-p shows largest charge collection Charge multiplication for large annealing (charge > e-) MCz: almost no dependence on annealing time 1.2*10 16 n eq /cm 2 FZ-n: No signal at highest fluence for all annealing steps FZ-p: rise in signal for long annealing time MCz-p sensor didnt work for first annealing step MCz-n: no signal at T= -20°C Increasing fluence MCz-n T= -30°C

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Charge Collection overview Max: 24k Max: 22k Max: 15k/40k Max: 10k MCz-n T=-30°C No Signal at T=-20°C

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Signal to Noise P N 4. Lower limit, seed cut > 5 2. Same range FZ-n drops out 1. All quite good 3. p is better than n

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Charge multiplication Signal increases after Annealing of Signal to noise ratio doesnt decrease Large increase of leakage current

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Charge collection / multiplication Landau-Gauß-Fit broadens very much Peak is shifted to higher values Not a MIP signal any more usual distribution

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Charge collection / multiplication MPV cannot be determined very well MCz-n T=-30°C FZ-p + MCz-p T=-20°C

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Charge Collection / Signal to Noise Summary CC S/N T= -30°C MCz-n Charge multiplication 15d 337d

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Leakage Current Summary Charge multiplication 15d337d

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Neutron only / mixed irradiation Mixed irradiation F = 4.6*10 14 n eq /cm 2 F(p) = 0.8*10 14 n eq /cm 2 F(n) = 3.8*10 14 n eq /cm 2 Neutron only irradiation F(n) = 4.0*10 14 n eq /cm 2 1.Neutron only irradiation: FZ-n has smaller signal than MCz-n simulated by M. Huhtinen NIMA 491, , Mixed irradiation: No improvement in CC due to mixed irradiation G. Casse et al. Vertex2008:036, 2008 MCz FZ N-type

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Summary P-type materials showed higher charge collection and signal to noise FZ-p performance most interesting Charge multiplication only seen with FZ-p F > 1*10 15 n eq /cm 2, A > Manufacturer Micron Highest leakage current FZ-n showed largest dependence on annealing time Not usable at high fluences Charge collection of MCz materials does not anneal very much MCz-n is not working at T= -20°C at F=1.2*10 16 n eq /cm 2 Additional differences between n-type and p-type materials due to manufacturer? Compare to other studies: Charge multiplication study, HPK

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Thanks for your attention Diploma thesis of F. Petry (IEKP-KA/ ) Will be published soon: 27.pdf

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT BACKUP

19 th RD50 Workshop Robert Eber Institut für Experimentelle Kernphysik, KIT Prof. Max Mustermann - Title