1. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 1 - Grzegorz Deptuch gdeptuch@bnl.gov  Introduction to beam monitor Design and test results of MAPS for a novel technique of hadron theraphy beam monitoring  conclusions  Design of MimoTera  Use of Mimosa 5 as test vehicle  First results with mimotera (very fresh) SUCIMA– Silicon Ultra Fast Camera for Electron and Gamma Sources in Medical Applications EU funded, project led by M. Caccia (Universita’ dell’Insumbria Como, Italy) MIMOSA–Minimum Ionising particle MOS Active pixel sensor project led by M. Winter (IReS/LEPSI  IPHC Strasbourg, France)

2. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 2 -  Introduction to beam monitor Hadrontherapy  real time beam monitoring 60-250 MeV p, 120-400 MeV 12 C 6+ Innovative Non-Destructive Beam Monitor for the Extraction Lines of a Hadrontherapy Centre vacuum chamber secondary emission foil electron detector PROFILE/CURRENT MEASUREMENT hadron beam e - beam HV 20 keV SEM electrons from 0.1 – 0.4 µm thick (Al-Al 2 O 3 -Al) foils 5  5000 rad/s (0.05  50 Gy/s)  10 kHz frame rate (<2% dose non-uniformity),  beam 70×70 mm 2  demagnification ×5,  beam image granularity ~1 mm  pixel pitch ~200  m,  active area matrix of minimum 5000 pixels,  signal range single e - to 9×10 3 e - /pixel every 100 µs,  sensitivity to 20 keV e -,  no dead time. Thinned and back side illuminated detector required choice – dedicated MAPS sensor

3. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 3 -  Introduction to beam monitor SLIM ( SEM for low interception monitor ) electrostatic cross-focusing demagnification system Foil Voltage: -20000 V CageVoltage: -20000 V Ring Voltage: -18900 V Cylinder 1: -13200 V Cylinder 2 + Detector: 0 V

4. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 4 -  MIMOSA 5,  MIMOSA 5, 512 × 512 pixels, 1 × 10 6 pixels, 0.6 µm CMOS process with 14 µm epi, pixel: 17 × 17 µm 2, diodes: P1 - 9.6 pm 2, P2 - 24.0 pm 2, control logic and all pads aligned along one side,  Use of Mimosa 5 as test vehicle not optimised for any particular application, general development – IReS-LEPSI work in 2001

5. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 5 -  Readout time = Integration time ~8 ms @ 40 MHz f clk.  Frame subtraction = CDS, (in DAS – hardware or data analysis – software)  Use of Mimosa 5 as test vehicle very efficient approach because single frame noise much higher than only kTC – usually a lot of substrate pick-up during reset plus reset inefficiency

6. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 6 -  Use of Mimosa 5 as test vehicle  back-side sensitivity with “0” dead layer (MIMOSA 5)

7. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 7 -  20.0 kV Reconstructed signal clusters ~60k hitsCooling ~0°C  Use of Mimosa 5 as test vehicle

8. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 8 -  4kV – 20kV  Close to linear dependence «signal magnitude v.s. accelerating voltage» for ~10 – 20 keV;  Despite of poor precision, result between 0.5 keV and 1 keV, when the last 4 points are taken, is in a good agreement with simulations of electron interactions in the detector. Peak positions of signal distributions Cooling ~0°C  Use of Mimosa 5 as test vehicle

9. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 9 -  Asserting usefulness of MAPS for imaging by direct conversion of incident energy of electrons into e - h + pairs in silicon for future STEM and TEM. Competitive approach to currently used image plates and scintillator coupled cameras measurements of PSF in SEM set-up (6-30 keV electrons) on back-side illuminated MIMOSA 5  Use of Mimosa 5 as test vehicle

10. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 10 -  Dedicated MAPS design to beam monitoring  CVF=~250nV/e - @ 500fF; noise ~1000 e -  280 e - kTC (ENC) @ 500fF,  Design of Mimotera  pixel 153×153 µm 2 square pixels,  two 9×9 interdigited arrays of n-well/p-epi diodes (5×5 µm 2 ) + two independent electronics – avoiding dead area,  In-pixel storage capacitors – choice ~0.5 pF or ~5 pF to cope with signal range (poly1 over tox capacitors),  Readout without CDS – kTC noise, 153  m

11. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 11 -  Design of Mimotera  pixel design aiming low leakage current accumulation of positive charges in STI/FOX – inversion of p-type material at the interface and conduction path, high density of trap sites along trench walls (crystal orientation) and at the bottom of the trench (RIE) – current generation, accumulation of positive charges and charged ( + or - ) occupied traps - distribution of electric field in the device. Avoided:

12. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 12 -  Design of Mimotera Subarray 0 Subarray 1Subarray 2Subarray 3 17.136×17.136 mm 2 digital 28 columns(30 clocks) 112 rows(114 clocks) MimoTera  chip size: 17350×19607µm 2,  array 112×112 square pixels,  four sub-arrays of 28×112 pixels read out in parallel  read/integr <100µs,  AMS CUA 0.6 µm CMOS 14 µm epi,  no dead time – alternate integration and readout in halves of pixels,

13. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 13 -  Design of Mimotera  array of pixel  column level circuitry; 2 levels of source followers  adjustable gain output buffer  3:1 analog MUX

14. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 14 -  Design of Mimotera  big load capacitances on vertical and horizontal access lines,  increase of readout speed by multiplexing readout lines with advanced stabilization,  Design for speed  unequal speed for both signal polarities for source follower, v_pull_down  source follower output pulled down (N) / up (P) before readout,

15. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 15 -  First results of Mimotera  Tests with  241 Am source All reconstructed hits projected on a single image - frame A and frame B for small conversion capacitance distance from detector ~1cm (E=4MeV) + charge shared equally between two arrays of diodes 4×10 6 / 3.6 / 2 = 555,000 e - maximum signals measured 250 mV (output) 250 / 5 / 0.8 = 62.5 mV CVF=112 nV/e - (small conversion capacitance); 3.5 × difference for big capacitance 1.42pF small capacitance  <4000 e - ENC

16. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 16 -  First results of Mimotera  Tests with pulsed laser system (clusters of arbitrary multiplicity) ~5×10 6 e -

17. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 17 -  First results of Mimotera  Tests on 17 MeV p beam in SLIM at JRC Ispra, Italy  ~ 1 m upstream the SLIM

18. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 18 -  First results of Mimotera  nominal settings: 20.0 kV Al foil, 17.69 kV rings; the beam SLIM: un-measurably low (20 nA on the collimator).  Tests on 17 MeV p beam in SLIM at JRC Ispra, Italy

19. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 19 -  First results of Mimotera  Tests on 17 MeV p beam in SLIM at JRC Ispra, Italy  5 mm collimator ~2.2 mm  demagnification factor < 2.5 (expected 4 – beam divergence ?)  operation with beam currents from a few nA up to 1  A

20. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 20 -  Conclusions  Dedicated MAPS device for SLIM up and running!  correct operation of the chip (tested up to 20 MHz),  imaging capabilities tested with  241 Am (calibration of CVF difficult and not precise),  beam monitoring capabilities tested with p beam @ JRC Ispra, Italy.  Detailed analysis required to:  direct low energy electron detection capabilities demonstrated with backthinned MIMOSA 5 detector.  calibrate absolute CVF (typical X-ray source  – low signal - huge input capacitance, Poisson statistics method  – shot noise dominated by thermal noise),  verify input capacitance ratio; measured 3.5 – expected 8-10,  understand drifting of baseline (das?, chip?).  Prove of using MAPS technology for very specialized applications

21. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 21 -  MIMOTERA parameters MIMOTERA Size [pixel]112 x 112 Pixel pitch [  m 2 ] 153 x 153 Matrix size [mm 2 ]17.1 x 17.1 Max. frame rate [kHz]10 (tested 2 x slower) Dynamic range (20 keV e - ) 1 ÷ 1000 /pixel/100  s (high gain) 1 ÷ 15000 /pixel/100  s (low gain) MIMOTERA estimated parameters (preliminary) Conversion gain [nV/e - ]110 (small cap) 32 (big cap) Noise [e - ENC]2000-4000 Power [mW]200 Leakage currentto be measured Operation temp.RT

22. FEE2006, Perugia, MAY 17-20 2006Grzegorz DEPTUCH - 22 -  estimation of imaging performances for front and back side illuminated MAPS dependence on energy, strong presence of back-scattering differences between front side and back-side illuminated device sum + projection + normalisation sum + projection + normalisation on PCB on hole M5F: ~10  m SiO 2,15  m epi, 100  m substrate + PCB M5B: ~100 nm SiO 2,15  m epi, 500  m substrate + PCB  Use of Mimosa 5 as test vehicle SPARE SLIDE