1. Oct 2001 1 Monolithic pixel detector Update  One chip combining both sensor and read-out – source of ionization e- : epitaxial layer of chip – e- collected by a n-well – elegant, thin solution, or detector of the far future?  Progress on four known problems

2. Oct 2001 2 Problem # 1  fillFactory.com manufactures optical pixel-sensors with collection from epitaxial layer (US patent)  n-well to collect ionisation e- restricts transistors to n-MOS  makes it difficult to have on pixel electronics, amplifiers etc.

3. Oct 2001 3 Possible Solution to Problem #1  ISU engineers, add n-wells to house p-MOS transistors  p+ layer keeps potential minimum for ionization electrons to diffuse to collection n-well  foundry issues? simulation? n+ p-MOS n-MOS

4. Oct 2001 4 Problem #2 Quality of Silicon, Thickness epi-layer  LEPSI group used Austrian Mikro Systeme –17 micron epi-layer »1000 e-  STAR reproduced LEPSI work, used MOSES –8 micron epi-layer  Still an unresolved issue

5. Oct 2001 5 Problem #3: Existing Monolithic Slow  Current monolithic pixel detector (LEPSI) had one ADC per chip –very slow  Two designs being worked on by ISU engineers –copy circuit from active imaging devices »on each pixel, free-running pre-amplifier »sample-hold preamplifier output upon a Lvl1 signal »on each column, 3-4 bit flash ADC. (~1000 ADCs) »access sample/hold from each pixel and digitize u 50~100 pixels per column »timing being developed –copy NA60 readout electronics per pixel »on each pixel, amplifier, discriminator, buffer

6. Oct 2001 6 Problem #4 Mixed Analog/Digital  If we use discriminator and buffer on each pixel, possible digital noise corruption on analog signal –could use RHIC clock signal »no digital activity during first 20 ns after collision  If we use sample/hold on each pixel –no digital circuitry per pixel –digital circuitry at base of column

7. Oct 2001 7 Iowa State R&D  R&D project Electrical Engineering Profs/students at ISU –working on epitaxial layer, doping and foundry issues –laying out pixel electronics »on-pixel amplifier/sample-hold. Column ADC »on-pixel discriminator/pipeline from NA60  Goal is to have first design finished by Christmas –simulate –iterate –submit prototype in Spring 2002