AD2012 Ultra-Thin 3D detectors Celeste Fleta Instituto de Microelectrónica de Barcelona Celeste Fleta Instituto de Microelectrónica de Barcelona Centro Nacional de Microelectrónica - CSIC Spain [email protected]Ultra-Thin 3D Silicon Detectors for Active Neutron Detection
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RAD2012 Ultra-Thin 3D detectors Celeste FletaInstituto de Microelectrónica de Barcelona Celeste Fleta Instituto de Microelectrónica de Barcelona Centro.
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RAD2012 Ultra-Thin 3D detectors
Celeste Fleta Instituto de Microelectrónica de Barcelona
Celeste Fleta
Instituto de Microelectrónica de BarcelonaCentro Nacional de Microelectrónica - CSIC
300µm sensor 29.0±0.2 c/s90 mCi (2.8x109 γ/s in 4π)
1m distance
Lab source tests
241Am-Be + 137Cs
40 mCi AmBe (88000 n/s)8 mCi 137Cs
10cm polyethilene
800µm sensor 204.0±0.6 c/s
RAD2012 Ultra-Thin 3D detectors
Celeste Fleta Instituto de Microelectrónica de Barcelona
Hospital tests
sensor
Elekta Synergy (Hospital General de Catalunya) and Siemens Primus (Hospital de Santiago de Compostela)
6MV (γ only) and 15MV (γ + n)
10x10 cm2 field
50 to 500 MU/min*
*MU: a Monitor Unit is a measure of the machine output of a linac which is calibrated to deliver an absorbed dose under particular conditions, e.g. 100 MU gives 1 Gray in water at 100 cm SSD for a 10x10 cm2 field
RAD2012 Ultra-Thin 3D detectors
Celeste Fleta Instituto de Microelectrónica de Barcelona
Hospital tests
No pile-up counts observed
At 6 MV (γ only): 3.8 counts/min
1E6 γ/cm2s Gamma rejection factor: 2x10-9
At 15 MV: γ/n counts = 0.002 (sensor without/with H310BO3)
Fixed rate: Elekta Synergy, 400MU/min
H310BO3
RAD2012 Ultra-Thin 3D detectors
Celeste Fleta Instituto de Microelectrónica de Barcelona
Hospital tests
Variable rates: Siemens Primus, 15 MV
Linear response: no pile-up up to 500 MU/min• 50 MU/min: 4010±100 counts in 10 minutes• 500 MU/min: 4062±48 counts in 1 minute
γ/n rate = 0.02
System works well in pulsated gamma/neutron environment
H310BO3
RAD2012 Ultra-Thin 3D detectors
Celeste Fleta Instituto de Microelectrónica de Barcelona
Summary and outlook
Summary Innovative ultra-thin 3D silicon sensors with 10 µm thickness have been
successfully fabricated and adapted to detect neutrons with 10B-enriched compounds.
The detectors show a gamma rejection factor higher than 10-8 for 137Cs for a threshold of 100 keV, and 2x10-9 in a radiotherapy field.
Preliminary tests of the detectors in clinical linacs show their usefulness in these complex gamma-neutron pulsated radiation fields: low gamma count rate, linear up to at least 500 MU/min.
Ongoing work Working to integrate the system in a fully portable dosemeter. Developing 10B- based converter deposition tecniques. Working to obtain absolute efficiencies/gamma rejection factors with
calibrated sources. Developing microstructured detectors for higher neutron detection
efficiency.
C. Guardiola et al., “Ultra-thin 3D silicon sensors for neutron detection”, 2012 JINST 7 P03006
RAD2012 Ultra-Thin 3D detectors
Celeste Fleta Instituto de Microelectrónica de Barcelona
Thanks for your attention!
Full author list:C. Fleta, C. Guardiola, D. Quirion, J. Rodríguez, G. Pellegrini, J.P Balbuena, M. Lozano
Instituto de Microelectrónica de Barcelona, Barcelona, Spain
F. Gómez, X. González, D. González, J. Pardo Universidad de Santiago de Compostela, Santiago de Compostela, Spain
F. GarcíaHelsinki Institute of Physics, University of Helsinki, Helsinki, Finland