From: Andreas Neiser Date: Fri, 19 Apr 2013 14:50:47 +0000 (+0200) Subject: Added previous contributions X-Git-Url: https://jspc29.x-matter.uni-frankfurt.de/git/?a=commitdiff_plain;h=411aeef4cca9bbff0b5f1d06363b65d804cbc4e5;p=conferences.git Added previous contributions --- diff --git a/2012-twepp-traxler_ugur-fpga_digitisation/abstract.txt b/2012-twepp-traxler_ugur-fpga_digitisation/abstract.txt new file mode 100644 index 0000000..b272c89 --- /dev/null +++ b/2012-twepp-traxler_ugur-fpga_digitisation/abstract.txt @@ -0,0 +1,10 @@ +One of the most important aspects of particle identification +experiments is the digitisation of time, amplitude and charge data +from detectors. These conversions are done mostly with Application +Specific ICs (ASICs). However, the recent developments in Field +Programmable Gate Array (FPGA) technology allow us to use commercial +electronic components for the required Front-End Electronics (FEE) and +do the digitisation in the FPGA. It is possible to do Time-of-Flight +(ToF), Time-over-Threshold (ToT), amplitude and charge measurements +with converters implemented in FPGA. We call this principle come & +kiss: Use COMplex COMmercial Elements & Keep It Small and Simple. diff --git a/2012-twepp-traxler_ugur-fpga_digitisation/summary.txt b/2012-twepp-traxler_ugur-fpga_digitisation/summary.txt new file mode 100644 index 0000000..1d54eb0 --- /dev/null +++ b/2012-twepp-traxler_ugur-fpga_digitisation/summary.txt @@ -0,0 +1,51 @@ +Particle identification in nuclear physics experiments requires the +digitisation of analogue data generated by the detectors, such as +time, amplitude and charge information. Up to now digitisation of data +is done mainly by Application Specific Integrated Circuits (ASICs), +which requires a long time and a lot of resources for development. +With the recent developments in the Field Programmable Gate Array +(FPGA) technology, it is now possible to use FPGAs for data +digitisation by using complex commercial electronic components for the +necessary Front-End Electronics (FEE). We call this concept come & +kiss: COMplex COMmercial Elements & Keep It Small and Simple. + +To gain the time information (e.g., Time-of-Flight (ToF) or +Time-over-Threshold (ToT)) of a signal generated by the necessary +detectors, it is pre-amplified using available cell phone amplifiers +to a certain level. The amplified signal is digitised in an FPGA +differential input buffer used as a discriminator. By this +configuration the time information of the particle is encoded in the +rising and falling edges of a digital pulse. ToF measurements can be +carried out by measuring the rising edges of 2 signals, whereas the +ToT measurements can be done by measuring the pulse width of the +discriminated signal. For precise time measurements a Time-to-Digital +Converter (TDC) is implemented in the FPGA with high time resolution +(<15 ps RMS). + +For amplitude measurements an Analogue-to-Digital +Converter (ADC) can be implemented in a FPGA by means of a TDC. The +signal to be measured is applied to a differential input buffer of an +FPGA with a reference voltage generated by a linear sawtooth generator +on the second input. The differential buffer behaves as a comparator +and generates a digital signal at the crossing of the reference +sawtooth signal and the analogue signal. From the shape of the +reference signal and the switching time measured by the TDC the +amplitude of the input signal can be calculated. + +Charge measurements are done in a similar fashion. The charge of the +signal above the threshold is encoded in the width of a digital pulse +via a constant current discharge of the integrated signal. The width +of the pulse is proportional to the charge of the analogue signal. +Using a TDC the width of the pulse is measured and the charge value is +calculated. The FPGA based data digitisation has advantages over the +traditional ASIC solutions as well as disadvantages. The components +used for a come & kiss system, basic cell phone amplifiers and FPGAs, +are cheap and are always easily available removing the risks of mature +devices. This method doesn't require as much amount of time, resource +and cost as an ASIC design and has the advantage of being easily +adaptable to different requirements. Of course, creating a solution by +using commercial components is not as small as a special ASIC +solution. + +For all described digitisation methods test boards were developed and +the results and limits are presented.