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“Technology transfer of microstrip detectors; from Particle Physics to medical and synchrotron applications”. amplifier. Al strip. p +. +. +. SiO 2 /Si 3 N 4. -. -. +. n bulk. +. n +. -. + Vbias. HEP detectors - The microstrip. High resistivity (n) silicon - PowerPoint PPT Presentation
Citation preview
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
40000
45000
50000
55000
60000
65000
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