Radiation hard read-out electronics for microstrip elementary particle detectors
Today, modern elementary particle physics experiments are confronted with the problem to process enormous amounts of data to detect the tiny effects that yet have a big impact on our overall picture of the universe. This problem is solved by using highly integrated microelectronics.
The ASIC laboratory at Heidelberg developes the Beetle pipelined read-out chip which amplifies the weak signals of silicon micro-strip particle detectors. The chip can store them for some time before sending relevant data to the data acquistion system. A single chip reads out more than 100 channels, stores the signals for up to 4us before it sends the relevant data to the data acquisition system at a speed of 40MHz. The LHC-b experiment at CERN, Geneva, will read out about 450,000 data channels at a data rate of about 9TeraByte/s.
In addition the chip also provides prompt binary information with a reduced spatial resolution. These signals are intended for the selection of relevant data (i.e. trigger applications).
Due to the small dimensions of the detectors, the readout chips are located very close to the beam axis and inside the experiment's acceptance. Thus they are exposed to almost the same particle fluxes as the outer regions of the microstrip detectors themselves. Therfore the Beetle chip aims to survive a total dose of 10Mrad. To achieve this, special design and layout techniques and commercial deep submicron CMOS technology have been employed.
On a die size of only 6.1mm by 5.5 mm, the Beetle chip integrates not only 128 readout channels, but also a 128 by 160 samples analog memory. The picture shows a full-scale prototype chip being bonded to a PCB for testing.
Further information about the Beetle chip can be found on the home page of the project group in the ASIC lab.