HEP detectors - The microstrip

S. Manolopoulos

“Technology transfer of microstrip detectors;

from Particle Physics

to medical and synchrotron applications”

S. Manolopoulos1, C. Buttar2, M. Homer4, I. Redondo2, R. van Silfhoot6, S. Walsh5, S. Young3, J.Conway3

1CCLRC, 2Glasgow Univ., 3Sheffield Teaching Hospitals, 4Electron Tubes Ltd., 5MicronSemiconductor Ltd., 6 The University of Manchester

S. Manolopoulos

HEP detectors - The microstrip

Al strip

amplifier

SiO2/Si3N4

+ Vbias

+

+

+

+

--

-n bulk

p+

n+

• High resistivity (n) silicon

• Ion implants + Surface passivation

• AC or DC coupling

• Single sided (x) or double sided (x,y) r/o

• Integrated biasing schemes

• Intermediate (floating) strips for precision

• Double sided double metal line

DELPHICMS module

Manfred Krammer - HEPHY, ViennaManfred Krammer - HEPHY, Vienna

• 210 m2 of active silicon strip sensors

• 24,244 single silicon sensors

• 15 different sensor designs

• 16,000 modules• 9,600,000 strips =

electronics channels• 75,000 APV chips• 25,000,000 Bonds

S. Manolopoulos

Radiotherapy

Parotide glands

Optimised beams to deliver the

prescribed dose with

maximum sparing of the healthy tissue

RT

3D-CFRT

IMRT

S. Manolopoulos

IMRT modalities

S. Manolopoulos

“..In the early days .. it was feared that the concept of moving components greatly jeopardised the safety of radiation therapy..” [IMRT, Webb]

“..Currently, no single dosimeter is capable of providing all the necessary dose measurements; thus, compromises must be made..”

[IMRT-CWG, J Rad Onc v.51, 2001]

3D CRT fwd R.T.P. = define beam calculate doseVs

IMRT inv. R.T.P. = define (3D) dose calculate (optimum) beam

Dosimetric QA - IMRT

S. Manolopoulos

Technical Solutions

Aplic. Type Pros ConsIonisationChambers

absolute dose H20 equivalent direct r/o

x mm

single point no time info. (?)

TLDs cost in-vivo measurements

single point Indirect r/o no time info.

Film x << mm

cost 2D

Indirect r/o no time info non linear response

GEL cost volumetric meas. ( 3D )

r/o cost (MRI unit, single use) Integrating mode

IMRT

EPID 1 - 2D direct r/o real time

x < mm

cost

x , dead space (?) E, angle dep. (? : Ploeger et al. see

[Webb]) dead time - r/o speed (? : James et

al., Williams et al., see [Webb] )Film

x << mm cost

Indirect r/o , no time infoStereo.

Diodes direct r/o single point measurements

S. Manolopoulos

Dosimetric QA - IMRT

C De Wagter, J Phys: Conf. Series 3 (2004) pp/4-8

Scope to use linear arrays...

S. Manolopoulos

Project OSI

Micron semiconductor

“£”

PPARC“£”D

oH

S. Manolopoulos

1D detector

S. Manolopoulos

XDAS

XCHIP

Spec’s

• tint = 10 s - 1sec

• dead time = 1 s

• dyn. range = 15 pC

• sub-sampling

• Linearity > 99.9%

• read-out = 5 Mb/s

• Multi-module r/o

• Nmod < 63 (8064ch)

• 1000 £/module

S. Manolopoulos

OSI - 1st Lab. Tests

0 500 1000 1500

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

55000

60000

650000 5 10 15

0

5000

10000

15000

20000

25000

30000

35000

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45000

50000

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Linear Regression:Response = A + B * Q-------------------------------A = -24 ± 70 (ADU)B = 4349 ± 8 (ADU/pC)-------------------------------R = 0.99998

Res

pons

e (

AD

U )

Vpulser

( mV )

data fit

Q ( pC )

Non-linearity

1.1 %

S. Manolopoulos

Hospital Measurements - static

50 55 60 65 70

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Re

spon

se (

a.u

.)

x (mm)

data (f ilm) fit (f ilm) data (prototype) fit (prototype)

Penumbra

x80%-20%

= 3.9 ± 0.2 mm (Film)

x80%-20%

= 3.7 ± 0.2 mm (prototype)

S. Manolopoulos

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 320

1000

2000

3000

4000

N (

AD

U)

X (mm)

45 Dynamnic Wedge600 Mu/min, 100cm SSD, d

max

Hospital Measurements - dynamic

S. Manolopoulos

SR applic’s - BPM

S. Manolopoulos

SR applic’s - BPM0.48

0.47

0.46

0.45

0.44

0.43

0.42

6005004003002001000

Elapsed Time [s]

1150

1100

1050

1000

950

6005004003002001000

Elapsed Time [s]

1.92

1.91

1.90

1.89

1.88200150100500

Elapsed Time [s]

f = a + b*e-t/1 + c*e-t/2

1 = 11 sec

2 = 158 sec

Beam Stability

Beam drift = 30 m/hr

S. Manolopoulos

0 2000 4000 6000 8000 10000 12000

30

40

50

150

200

250

300

N (

au)

t (sec)

pixel 55 57 73

Beam StabilityESRF

3hr 30min

Refil

SR applic’s - BPM

3 4 5 6 7 8 9 100

50

100

150

200

250

300

N (

au)

position (mm)

Acquisition time 18:00 23:00

Beam Dirft

Drift ~ 2 mm/ 5 hrs ~ 400 μm/hr

S. Manolopoulos

Summary & Conclusions

•Technology transfer is a good thing The “OSI” experience:

• Improved performance over present “Au” standard (temporal info.)

and best commercial systems (spatial info.) leading to...

• ….Improved (NHS) services (treatment, throughput)...

• ….Wealth creation (new markets for UK industry & RC…)

The ESRF experience : More effective beam time use - less time 4 setting-up & problem solving...….Higher user throughput AND better experiments

• Lessons learned - Useful tips :

•Needs a problem (its good to talk)•Needs an idea (or two..) “I think there4 I am”•Needs a “total” solution provider (call EID)

S. Manolopoulos

OSI Options - 2D

Inte

rfac

e

adap

tor

XDAS

1

2

.

.

.

22

1 2 . . . 22

Interface adaptor

XDAS

Spec’s :

• 22 x 22 matrix

• 484 pixels

• 4 XDAS boards

• pixel size = 0.455 mm

• Area = 1 cm

Aim = Stereotaxy

S. Manolopoulos

OSI Options - 1D

““Performance” :Performance” :

• FoV ~ 10 x 10 cm2

• x < mm

• real time r/o

• Cost (…)

• Energy Independ.

• Angle Independ.

• 2D

• H20 eq.

#1

#2

#3

#4

XDASDetector

PC

Specifications:

• Single crystal - Si

• 512 chan. ( 128 x 4 )

• 0.2 mm pitch

• tINT > 10 sec

• 1 kHz frame rate

• External Trigger

• Qmax = 15 pC

S. Manolopoulos

Hospital Measurements - dynamic

S. Manolopoulos

SR applic’s - BPM

1400

1300

1200

1100

1000

900

80084008200800078007600

Elapsed Time [s]

0.50

0.48

0.46

0.44

0.42

0.40

0.38

0.36

Beam Oscillations

T = 28 sec