"Development of Position and Time Sensing APSs for Tracking and Vertexing at the ILC"
- What are the goals of this R&D project. How does this R&D project address the needs of one or more of the detector concepts?
The goal of this R&D is to develop a new type of Active Pixel Sensors (APSs) to track charged particles produced at the intersection region of International Linear Collider (ILC). The electric field of the desirable shape is created inside the active volume of the pixel, introducing the drift component in movement of the signal electrons toward charge collecting electrodes. Sharing of the signal electrons between adjacent pixels by diffusion is strongly reduced with respect to classical APS devices. The proposed sensor is fabricated using a standard industrially available Complementary Metal Oxide Silicon (CMOS) process. It represents a large improvement of the state of the art of sensors for detection of position and of the time of occurrence of charged particles crossing the sensors. There are two main advantages of the proposed detectors as compared to the present (2005) state of the art. The first advantage is the reduction of the charge collection time thanks to the added transport mechanism (drift). The second advantage is the freedom to use of both kinds of MOS transistors within each pixel of the sensor. Thus, the full functional power of CMOS architecture can be embedded in situ. The reduced collection time combined with the state of the art electronics within each pixel provides the most complete information about the position and the timing of incident charged particles. Position resolution of a few microns is the retained from standard APSs. Timing precision should be about 100ns. Moreover, the active depth of the sensor and the associate electronics is less than about 20 microns and a thinned down sensor together with its beryllium backing can have the total thickness of less than 0.1% of one radiation length. The reduction of the thickness of the detector reduces the amount of multiple scattering within the detector. The determination of the momenta and of the origins of particles can be improved. The proposed APSs should be radiation resistant.
- If there are multiple institutions participating in this project, please describe the distribution of responsibilities
BNL Â 1) Design of epitaxial layer with optimized drift field,
2) Partial design of front end electronics,
3) Testing
Milan  1) Partial design of front end electronics,
2) Partial design of timing logic
Stony Brook  1) Partial design of timing logic,
2) Testing
Strasbourg  1) Thinning,
2) Testing
- Are there significant recent results?
No hardware has yet been produced. Only results are of simulations which confirm the idea behind the project.
- What are the plans for the near future(about 1 year)? What are the plans on a time scale of 2 to 3 years
Within about 1 year from obtaining funding we shall have a working prototype with arrays of lower number of pixels.
Within about 2 years we shall have prototypes of full size arrays without any attempt of thinning.
Within about 3 years we shall have prototypes of thinned down Active Pixel Sensors.
- Are there critical items that must be addressed before significant results can be obtained from this project?
No. The most critical question, that is, the independence of the hole current generating the field and signal current of electrons was already proven by a test of the pre-prototype of Strasbourg collaborators.
- Is the support for this project sufficient? Are there significant improvements that could be made with additional support?
No. The project is not yet supported. No progress can be made without (additional) support.
Please address the following questions in your statement.
- What are the goals of this R&D project. How does this R&D project address the needs of one or more of the detector concepts?
- If there are multiple institutions participating in this project, please describe the distribution of responsibilities.
- Are there significant recent results?
- What are the plans for the near future(about 1 year)? What are the plans on a time scale of 2 to 3 years?
- Are there critical items that must be addressed before significant results can be obtained from this project?
- Is the support for this project sufficient? Are there significant improvements that could be made with additional support?
