FEE2006, Perugia, MAY 17-20 2006

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Grzegorz DEPTUCH

Grzegorz Deptuchgdeptuch@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 ApplicationsEU funded, project led by M. Caccia (Universita’ dell’Insumbria Como, Italy)

MIMOSA–Minimum Ionising particle MOS Active pixel sensorproject led by M. Winter (IReS/LEPSI IPHC Strasbourg, France)

FEE2006, Perugia, MAY 17-20 2006

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Introduction to beam monitor Hadrontherapy real timereal time beam monitoring beam monitoring 60-250 MeV p, 120-400 MeV 60-250 MeV p, 120-400 MeV 1212CC6+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- beamHV

20 keV

SEM electrons from 0.1 – 0.4 µm thick

(Al-Al2O3-Al) foils

5 5000 rad/s (0.05 50 Gy/s)

10 kHz frame rate (<2% dose non-uniformity)10 kHz frame rate (<2% dose non-uniformity),, beam 70beam 70××70 mm70 mm22 demagnification demagnification ××5,5, beam image granularity ~1 mm beam image granularity ~1 mm pixel pitch ~200 pixel pitch ~200 m,m, active area matrix of minimum 5000 pixelsactive area matrix of minimum 5000 pixels,, signal range single signal range single ee-- to 9to 9×10×1033 e e--/pixel every 100 µs/pixel every 100 µs,, sensitivity to 20 keV esensitivity to 20 keV e--,, no dead timeno dead time..

Thinned and back side illuminated detector required

choice – dedicated MAPS sensor

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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

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MIMOSA 5, MIMOSA 5, 512 × 512 pixels, 1 × 106 pixels, 0.6 µm CMOS process with 14 µm epi, pixel: 17 × 17 µm2, diodes: P1 - 9.6 pm2, P2 - 24.0 pm2, 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

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Readout time = Integration time ~8 ms @ 40 MHz fclk.

Frame subtraction = CDS, (in DAS – hardware or data analysis – software)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

FEE2006, Perugia, MAY 17-20 2006

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Grzegorz DEPTUCH

Use of Mimosa 5 as test vehicle back-side sensitivity with “0” dead layerback-side sensitivity with “0” dead layer (MIMOSA 5) (MIMOSA 5)

FEE2006, Perugia, MAY 17-20 2006

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20.0 kV

Reconstructed signal clusters~60k hitsCooling ~0°C

Use

of M

imos

a 5

as t

est

vehi

cle

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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 distributionsCooling ~0°C

Use of Mimosa 5 as test vehicle

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2

4 2

4

0

0.25

0.5

0.75

1

2

4

0

0.25

0.5

0.75

1

2

4 2

4

0

0.25

0.5

0.75

1

2

4

0

0.25

0.5

0.75

1

2

4 2

4

0

0.25

0.5

0.75

1

2

4

0

0.25

0.5

0.75

1

Asserting usefulness of MAPS for imaging by direct conversion of incident energy of Asserting usefulness of MAPS for imaging by direct conversion of incident energy of electrons into eelectrons into e--hh++ pairs in silicon for future STEM and TEM. pairs in silicon for future STEM and TEM.

Competitive approach to currently used image plates and scintillator coupled cameras Competitive approach to currently used image plates and scintillator coupled cameras

measurements of PSF measurements of PSF in SEM set-up in SEM set-up (6-30 keV electrons) (6-30 keV electrons) on back-side on back-side illuminated MIMOSAilluminated MIMOSA 5 5

Use of Mimosa 5 as test vehicle

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Dedicated MAPS design to beam monitoringDedicated MAPS design to beam monitoring

CVF=~250nV/e- @ 500fF; noise ~1000 e- 280 e- kTC (ENC) @ 500fF,

Design of Mimotera

pixel 153×153 µm2 square pixels,

two 9×9 interdigited arrays of n-well/p-epi diodes (5×5 µm2) + 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

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Design of Mimotera pixel design aiming low leakage currentpixel 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:

FEE2006, Perugia, MAY 17-20 2006

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Design of Mimotera

Suba

rray

0 Su

barr

ay

1 Suba

rray

2 Su

barr

ay

3

17.136 × 17.136 mm2

digital

28 columns (30 clocks)

112 rows (114 clocks)

MimoTera

chip size: 17350×19607µm2,

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,

FEE2006, Perugia, MAY 17-20 2006

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Design of Mimotera

array of pixel

column level circuitry; 2 levels of source followers

adjustable gain output buffer 3:1 analog MUX

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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 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,

FEE2006, Perugia, MAY 17-20 2006

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First results of Mimotera Tests with Tests with 241241Am sourceAm 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

4×106 / 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

FEE2006, Perugia, MAY 17-20 2006

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First results of Mimotera Tests with pulsed laser systemTests with pulsed laser system

(clusters of arbitrary multiplicity)

~5×106 e-

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First results of Mimotera Tests on 17 MeV p beam in SLIM Tests on 17 MeV p beam in SLIM at JRC Ispra, Italyat JRC Ispra, Italy

~ 1 m upstream the SLIM

FEE2006, Perugia, MAY 17-20 2006

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First results of Mimotera

nominal settingsnominal settings: 20.0 kV Al foil,: 20.0 kV Al foil, 17.69 kV rings 17.69 kV rings;; the the beam beam SLIM: unSLIM: un--measurably low measurably low (20 nA on the collimator)(20 nA on the collimator). .

Tests on 17 MeV p beam in SLIM at JRC Ispra, ItalyTests on 17 MeV p beam in SLIM at JRC Ispra, Italy

FEE2006, Perugia, MAY 17-20 2006

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Grzegorz DEPTUCH

First results of Mimotera Tests on 17 MeV p beam in SLIM at JRC Ispra, ItalyTests 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

FEE2006, Perugia, MAY 17-20 2006

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Conclusions

Dedicated MAPS device for SLIM up and running! correct operation of the chip (tested up to 20 MHz)correct operation of the chip (tested up to 20 MHz),, imaging capabilities tested with imaging capabilities tested with 241241Am (calibration of CVF difficult and not precise)Am (calibration of CVF difficult and not precise),, beam monitoring capabilities tested with p beam @ JRC Ispra, Italy.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 calibrate absolute CVF (typical X-ray source – low signal - huge input capacitance, – low signal - huge input capacitance, Poisson statistics method Poisson statistics method – shot noise dominated by thermal noise) – shot noise dominated by thermal noise),, verify input capacitance ratio; measured 3.5 – expected 8-10verify input capacitance ratio; measured 3.5 – expected 8-10,, understand drifting of baseline (das?, chip?).understand drifting of baseline (das?, chip?).

Prove of using MAPS technology for very specialized applications

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MIMOTERA parametersMIMOTERAMIMOTERA

Size [pixel] 112 x 112

Pixel pitch [m2] 153 x 153

Matrix size [mm2] 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 (MIMOTERA estimated parameters (preliminarypreliminary))

Conversion gain [nV/e-] 110 (small cap) 32 (big cap)

Noise [e- ENC] 2000-4000

Power [mW] 200

Leakage current to be measured

Operation temp. RT

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estimation of estimation of imaging performances imaging performances for front and back side for front and back side illuminated MAPSilluminated MAPS

dependence on energy, strong presence of back-scatteringdependence on energy, strong presence of back-scatteringdifferences between front side and back-side illuminated devicedifferences between front side and back-side illuminated device

sum + sum + projection + projection + normalisationnormalisation

on PCBon PCBon holeon hole

M5F: ~10M5F: ~10 m SiOm SiO22,15,15m epi, m epi, 100100 m substrate + PCBm substrate + PCBM5B: ~100M5B: ~100 nm SiOnm SiO22,15,15m epi, m epi, 500500 m substrate + PCBm substrate + PCB

Use of Mimosa 5 as test vehicle SPARE SLIDESPARE SLIDE