Disruptive Technologies for Electron Bombarded Active Pixel Sensors
Lead Research Organisation:
European Organization for Nuclear Research
Department Name: Theoretical and Experimental Physics
Abstract
A variety of sensor types have been operated in electron bombarded mode, including CCDs CMOS sensors, and silicon sensors (pixellated photodiodes) in conjunction with active pixel sensors (e.g. Medipix [2]). This project aims to develop a photon counting capability for the TDCpix [3], a newly developed pixel sensor with exceptional timing resolution. It follows on from a previous PIPSS and BBSRC-funded collaboration with CERN to develop a multi-channel photon-counting detectors with picosecond event timing for life science applications. Our original IPS project utilized a microchannel plate detector with CERN-developed preamplifier and time-to-digital ASICs. The recent development of the TDCpix active pixel sensor by the same group at CERN offers comparable time resolution
(100 ps binning, and electronic resolution ~30ps) but with a much higher pixel count (40 x 45 pixels, 12 x 13.5mm^2)), a much higher level of miniaturization provided by integration of the entire electronics on to the chip, and a greatly increased overall count rate capability of ~130 Mcount/s per ASIC, an order of magnitude higher per unit area than its microchannel plate based predecessor.
An electron bombarded TDCpix would offer unrivalled performance with commercial potential for applications using time-correlated single photon counting (TCSPC) such as high content cell screening and other expanding fields in the life science sector, LIDAR instruments for remote sensing, and a variety of other event timing applications where only small arrays of individual photomultiplier tubes are the norm.
Our aim in this project is to identify and develop a technology for photon counting detectors using electron bombarded silicon devices, in order to remove the active pixel sensor from within the vacuum tube, thus greatly simplifying design, de-risking the manufacturing process, and enhancing performance. Removing the chip from the tube will eliminate undesirable elements such as high density vacuum electrical feedthroughs, materials with poor vacuum compatibility, and internal bump, wire, and chip bonding, and will lift the restrictions imposed by these on tube processing which impact manufacturing yield, device reliability, and ultimately, sensor lifetime. Given a successful outcome to this project, we intend to propose a follow-on IPS project, one of whose goals would be to incorporate an additional, relatively low (x20) gain stage using a linear mode electron avalanche process within each pixel of the silicon sensor, matched to the requirements of electron bombarded operation. This will allow the electron bombardment gain to be lowered, reducing the tube operating voltage to safer levels, and reducing the lifetime-threatening radiation damage.
The other elements of an electron bombarded detector design, the vacuum tube including photocathode, and the silicon sensor, will be provided by our industrial collaborators; Photek Ltd., and Micron Semiconductor Ltd, respectively. Photek have extensive experience of design and manufacture of custom vacuum-based detectors with specific expertise in the electron bombarded mode devices, having manufactured an electron bombarded Medipix-based detector. Micron Semiconductor have substantial experience and heritage producing large quantities of custom pixellated silicon sensors for harsh radiation environments at CERN LHC and other similar experiments. Specifically for this project, they have developed a thin entrance window technology which is highly desirable for electron bombarded mode to minimize photoelectron energy loss. The thickness of their currently available Type-9.5 window is 500 Angstroms, and a Type-10 window is under development with a thickness goal of 200 Angstroms. Micron also have a bump-bonding capability necessary for the interconnect development.
(100 ps binning, and electronic resolution ~30ps) but with a much higher pixel count (40 x 45 pixels, 12 x 13.5mm^2)), a much higher level of miniaturization provided by integration of the entire electronics on to the chip, and a greatly increased overall count rate capability of ~130 Mcount/s per ASIC, an order of magnitude higher per unit area than its microchannel plate based predecessor.
An electron bombarded TDCpix would offer unrivalled performance with commercial potential for applications using time-correlated single photon counting (TCSPC) such as high content cell screening and other expanding fields in the life science sector, LIDAR instruments for remote sensing, and a variety of other event timing applications where only small arrays of individual photomultiplier tubes are the norm.
Our aim in this project is to identify and develop a technology for photon counting detectors using electron bombarded silicon devices, in order to remove the active pixel sensor from within the vacuum tube, thus greatly simplifying design, de-risking the manufacturing process, and enhancing performance. Removing the chip from the tube will eliminate undesirable elements such as high density vacuum electrical feedthroughs, materials with poor vacuum compatibility, and internal bump, wire, and chip bonding, and will lift the restrictions imposed by these on tube processing which impact manufacturing yield, device reliability, and ultimately, sensor lifetime. Given a successful outcome to this project, we intend to propose a follow-on IPS project, one of whose goals would be to incorporate an additional, relatively low (x20) gain stage using a linear mode electron avalanche process within each pixel of the silicon sensor, matched to the requirements of electron bombarded operation. This will allow the electron bombardment gain to be lowered, reducing the tube operating voltage to safer levels, and reducing the lifetime-threatening radiation damage.
The other elements of an electron bombarded detector design, the vacuum tube including photocathode, and the silicon sensor, will be provided by our industrial collaborators; Photek Ltd., and Micron Semiconductor Ltd, respectively. Photek have extensive experience of design and manufacture of custom vacuum-based detectors with specific expertise in the electron bombarded mode devices, having manufactured an electron bombarded Medipix-based detector. Micron Semiconductor have substantial experience and heritage producing large quantities of custom pixellated silicon sensors for harsh radiation environments at CERN LHC and other similar experiments. Specifically for this project, they have developed a thin entrance window technology which is highly desirable for electron bombarded mode to minimize photoelectron energy loss. The thickness of their currently available Type-9.5 window is 500 Angstroms, and a Type-10 window is under development with a thickness goal of 200 Angstroms. Micron also have a bump-bonding capability necessary for the interconnect development.
People |
ORCID iD |
Hartmut Hillemanns (Principal Investigator) |
Description | Though suffering from significant delays and setbacks in the production of a essential hardware item due to various technological difficulties, we have succeed to finally procure this item, and to make available prototypes based on this item for further use by our project partners (Leicester University and Photek Ltd, see also ST/K003062/1), so that further testing can continue as from Q2/2016. Despite the project officially having finished, CERN will continue to provide support necessary to finalise a prototype device and to maximise its prospects of use in various application domains. |
Exploitation Route | CERNs contribution to the project consisted of providing readout ASIC, connection technologies and test system exploitable by our project partners (Leicester University and Photek SA) for use in various time-correlated single photon counting applications. For more details regarding the potential use and the impact of this technology, please refer to the reporting provided by our project partners (ST/K003062/1). |
Sectors | Aerospace Defence and Marine Electronics Environment Healthcare Manufacturing including Industrial Biotechology Pharmaceuticals and Medical Biotechnology Security and Diplomacy Other |
Description | Electron bombarded (EB) mode operation can confer single photon counting sensitivity to the expanding range of active pixel sensors becoming available, which offer ever larger pixel formats and improved timing characteristics. An EB sensor is a hybrid combination of vacuum photodiode tube with solid state sensor. This project aims to provide proof-of-concept level technology solutions to overcome the practical and operational constraints which have thus far limited the success and commercial uptake of this technology. Our overall programme has two major goals: firstly to simplify device manufacture and improve reliability and performance by removing the pixel chip from the vacuum vessel, and secondly, to improve operational characteristics and device lifetime by adding an avalanche gain process within the silicon sensor (SS). Within this Mini-IPS proposal we will demonstrate proof-of-concept for the higher risk key elements of our first goal, de-risking the manufacturing technology in preparation for a follow-on project in which we will address our second goal, the addition of avalanche gain, culminating in demonstration of a full commercial prototype using a ground-breaking pixel chip developed at CERN, the TDCpix, a pixel chip with 100 ps event timing capability and 40 x 45 pixel sq. format. Even though officially terminated CERN continues to collaborate with its project partners in providing support necessary to demonstrate the feasibility of a prototype. Once successfully tested, we will be in the position to report on impact. |
First Year Of Impact | 2016 |
Impact Types | Economic |
Description | Disruptive Technologies for electron bombarded active pixel sensors |
Organisation | Photek Ltd. |
Country | United Kingdom |
Sector | Private |
PI Contribution | Design and manufacturing of a high time resolution ASIC for the readout of the active pixel sensor Development of a test setup and support for training for its use Manufacturing of a 3D interposer to ensure a reliable connectivity between the electron sensitive element and the pixel readout ASIC outside the device |
Collaborator Contribution | Integration, overall project management Manufacturing of demonstrator prototype devices |
Impact | The project is in an early stage and first outcomes are expected by the end of 2016 |
Start Year | 2013 |
Description | Disruptive Technologies for electron bombarded active pixel sensors |
Organisation | University of Leicester |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Design and manufacturing of a high time resolution ASIC for the readout of the active pixel sensor Development of a test setup and support for training for its use Manufacturing of a 3D interposer to ensure a reliable connectivity between the electron sensitive element and the pixel readout ASIC outside the device |
Collaborator Contribution | Integration, overall project management Manufacturing of demonstrator prototype devices |
Impact | The project is in an early stage and first outcomes are expected by the end of 2016 |
Start Year | 2013 |