ILC accelerator worst case assumptions ====================================== Beam crossing period = 150ns, so rate = 6.7MHz Number of crossings per train = 14000, so length = 2ms Train repetition rate = 10Hz, so period = 100ms and duty factor = 2% Luminosity = 5x10^34/cm^2/s, so integrated lumi per train = 5/nb MAPS Requirements ================= Pixel response: The pixels must give one hit per charged particle crossing the sensor. This is of course impossible in practise but is the ideal we should aim to be close to. Some guesses at requirements resulting from this are: o Maximum inefficiency (defined as one particle giving no hit) = 5% within pixel (also see below). o Maximum crosstalk (defined as one particle giving two hits) = 5% (?) within pixel. o Maximum noise hit rate 10^-5, target rate 10^-6. The noise rate must be insensitive to expected temperature changes (tbd). o Maximum dead space = 10%. Working assumption is that basic sensor structure is 2x2cm^2 with a 250mu contact pad strip around the outside. This gives 5% dead space; the other 5% is random dead areas over the pixels (bad pixels, non-sensitive n-well areas, etc), as above. A working assumption is that the pixel size should be in the range: o minimum size 20x20mu^2, maximum size 60x60mu^2. Comparator: The requirements here are: o The comparator/storage cycle time must occur within 100ns of a trigger signal. o The trigger should be able to come a minimum of 50ns after the particles cross the sensor. o The comparator threshold must be set/trimmed by on-sensor DAC. The DAC should be common to multiple pixels, which are therefore required to be uniform. o The threshold setting must be insensitive to expected temperature changes. Working assumptions are: o Triggers will have minimum spacing of 150ns but could be arbitrary times apart (many seconds for cosmics). o Worsening the time resolution to more than 150ns could be done if necessary but is not very desirable. Memory: The requirements here are: o The timestamps can require up to 16 bits. o The memory needs to be able to hold data for at least hundreds of ms for ILC operation. For beam tests, sources and cosmics, it would be useful to have the memory hold data for many seconds. o All data in memories must be able to be read out within 98ms under normal conditions (reasonable occupancy, etc, tbd). o Bad pixels should be able to be masked. o Pixels with no hits should be ignored during readout. A working assumption is: o The minimum number of allowed timestamps = 4, maximum number = 16. External contacts: The requirements here are: o The contacts should mechanically allow the sensor to be placed inverted on a PCB preferably using standard BGA-like solder technology. o All required I/O termination circuitry should be within the sensor. o No substrate ground should be needed. o Data output must be able to drive signals down 1.5m tracks on a PCB. Power: The maximum averaged power during timing equivalent to ILC operation must be 1 uW/mm^2.