Silicon pixel detectors for Synchrotron beam lines

Lead Research Organisation: University of Glasgow
Department Name: School of Physics and Astronomy


The project aims to build on existing work in the University of Glasgow and Diamond detector development group to investigate novel silicon pixel detector architectures applicable to use at the Diamond Synchrotron. The student will work in the Glasgow detector development group with Dr Richard Bates (head of 3D detector group in the RD50 collaboration) and Dr Andrew Blue (expert on APS sensor testing), and in the Diamond Detector group with Dr Nicola Tartoni (head of Diamond detector group) and Dr Julien Marchal (detector expert with particular responsibility for organising testbeam activities in this project). The supervising academic staff member will be Dr Chris Parkes (head of Glasgow RD50 activities). Two technologies will be investigated: 1) Small dimension hybrid pixel devices with reduced charge sharing for use on 10-20 KeV X-ray beam lines 2) Active pixel sensors for soft x-ray diffraction, and high energy beam line real-time applications. The student will primarily concentrate on detector testing and characterisation, both in the Glasgow laboratory and on Diamond beamlines. Device modeling will be performed to underpin the analysis of the results. The student will spend part of their time at the University of Glasgow and part at the Diamond Synchrotron, depending on the project needs. The student will undertake the relevant PhD training courses at the University of Glasgow. 1) Hybrid Pixel Devices Currently existing commercial hybrid pixel devices are based on 170x170 micron pixels (in the state-of-the-art Pilatus system used at Diamond). At Diamond the needs for smaller pixel size silicon sensors have been clearly identified. Both the University of Glasgow and Diamond are members of the Medipix collaboration which produces single photon counting 55x55 micron pixel readout front-end electronics. However, conventional small pixel planar devices suffer from charge sharing between pixels. This can be addressed through either the use of 3D sensors to limit charge sharing or in the electronic read-out chip (or both). 3D sensors: This work builds on the highly successful previous CASE studentship which resulted in the design, simulation and first production of a novel 3D detector architecture sensor and the first 3D detector for synchrotron applications. These tests have demonstrated significantly reduced charge sharing. 3D fabrication techniques (applied to either 3D detectors or planar detectors) can yield edgeless devices which allow tiling of devices over an area, of obvious application to imaging at Diamond, and will be considered in a future production. Read-out Chip: The Medipix3 readout chip will soon be available which will attempt to reduce charge sharing through the electronic circuitry. The charge sharing in a conventional (as well as 3D) device will be compared against Medipix2. 2) APS Development Active pixel sensors (APS) have the key advantage over CCD devices that are conventionally used in Synchrotron applications, which is that the APS in-pixel electronics is configurable for the required application. At Diamond this has potential applications on soft X-ray diffraction beamlines (I10, I06) and, coupled with a scintillator, on High Energy beamlines (I15 and I12). Large area devices suitable for Synchrotron applications are producible from APS technology, and APS sensors can be readout with a high frame rate The University of Glasgow group, as part of MI3, has developed a setup and techniques for the characterisation of APS sensors. In recent years this has been applied to the characterisation of 4 types of APS sensor with dimensions from 45 micron down to 6 micron. APS sensors suitable for application at Diamond are already extant and will be tested in the early part of this CASE studentship. This initial study is likely to result (with additional grant applications) in suggestions to produce large area low noise APS sensors ideally tailored to Diamond applications.


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Akiba K (2012) Charged particle tracking with the Timepix ASIC in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

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Collaboration T (2012) Prototype ATLAS IBL modules using the FE-I4A front-end readout chip in Journal of Instrumentation

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Grenier P (2011) Test beam results of 3D silicon pixel sensors for the ATLAS upgrade in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

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Kohler M (2010) Beam Test Measurements With 3D-DDTC Silicon Strip Detectors on n-Type Substrate in IEEE Transactions on Nuclear Science

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Köhler M (2011) Comparative measurements of highly irradiated n-in-p and p-in-n 3D silicon strip detectors in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

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Köhler M (2011) Measurements with Irradiated 3D Silicon Strip Detectors in Nuclear Physics B - Proceedings Supplements

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Micelli A (2011) 3D-FBK pixel sensors: Recent beam tests results with irradiated devices in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Description We developed two types of silicon pixel detectors. The first is known as the 3D detector where we made an array of diodes and connected them to an amplifier array. The novelty is in the fact that the diode electrodes penetrate fully the detector. These were demonstrated, via our measurements, to give improved charge collection in that the charge spreading into neighbouring pixels was minimised and the speed of collection maximised. The devices were demonstrate to be very radiation hard to irradiation via hadrons. The second device type of detector we developed and tested is a CMOS sensor for X-ray photon detection for Synchrotrons applications. The CMOS camera gain and stability were determined, the dark current, noise, signal to noise and image lag performance was evaluated and compared between the CMOS sensor and a leading commercial CCD device. The CMOS device out-performed the CCD device.
Exploitation Route CMOS devices are being developed for the Synchrotron community by other groups and our findings have helped with this developed. I have an active CMOS development grant for CMOS sensors for Particle physics.
Our research into 3D detectors has been used to further the understanding of the sensor type, which has been successfully installed into the ATLAS experiment and will be further developed for the LHC experiments. Presently I am no longer working on 3D detectors.
Sectors Aerospace, Defence and Marine,Electronics,Healthcare,Manufacturing, including Industrial Biotechology,Security and Diplomacy

Description I believe that the work on CMOS sensors has benefited the general community in the development of the CMOS sensors for synchrotron applications and for other applications in general. The sensors were developed as part of a previous EPSRC basic technology grant MI3. This PhD grant worked on the detailed comparison of one of the CMOS devices produced by the MI3 collaboration (which I was a co-I on). The work lead to the Diamond detectors group to conclude that a CMOS device would be required to be developed for synchrotron applications.
First Year Of Impact 2012
Sector Electronics,Pharmaceuticals and Medical Biotechnology
Impact Types Economic

Title Micron sized focused X-ray beam scanning of semiconductor devices 
Description We have developed a new method to understand the charge collection inside a pixel sensor with the use of a micron focused X-ray beam. This has been performed at the Diamond Light source and we hope that we will be able to develop an in-house system with an X-ray tube. 
Type Of Material Improvements to research infrastructure 
Year Produced 2013 
Provided To Others? Yes  
Impact This method has been used for Diamond detectors at Manchester, silicon strip detectors for ATLAS with international groups including DESY and CNM Barcelona. 
Description Diamond light source 
Organisation Diamond Light Source
Country United Kingdom 
Sector Private 
PI Contribution We have a CASE award with them
Collaborator Contribution They have given us access to their labs and beam lines and supported our research via a CASE award
Impact CMOS detector characterisation Pixel sensor characterisation technique
Start Year 2011
Description School Visits 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Various school visits to give talks and demonstrations of pixel detectors.
Year(s) Of Engagement Activity 2011,2012,2013,2014,2015
Description talks at science festivals 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Presentations have been made to science festivals by the PDRA employed on this project. He has given talks and given interactive presentations of his work.
Year(s) Of Engagement Activity 2015,2016,2017