12,003 research outputs found
FPGA-Based Tracklet Approach to Level-1 Track Finding at CMS for the HL-LHC
During the High Luminosity LHC, the CMS detector will need charged particle
tracking at the hardware trigger level to maintain a manageable trigger rate
and achieve its physics goals. The tracklet approach is a track-finding
algorithm based on a road-search algorithm that has been implemented on
commercially available FPGA technology. The tracklet algorithm has achieved
high performance in track-finding and completes tracking within 3.4 s on a
Xilinx Virtex-7 FPGA. An overview of the algorithm and its implementation on an
FPGA is given, results are shown from a demonstrator test stand and system
performance studies are presented.Comment: Submitted to proceedings of Connecting The Dots/Intelligent Trackers
2017, Orsay, Franc
Improved Fast Neutron Spectroscopy via Detector Segmentation
Organic scintillators are widely used for fast neutron detection and
spectroscopy. Several effects complicate the interpretation of results from
detectors based upon these materials. First, fast neutrons will often leave a
detector before depositing all of their energy within it. Second, fast neutrons
will typically scatter several times within a detector, and there is a
non-proportional relationship between the energy of, and the scintillation
light produced by, each individual scatter; therefore, there is not a
deterministic relationship between the scintillation light observed and the
neutron energy deposited. Here we demonstrate a hardware technique for reducing
both of these effects. Use of a segmented detector allows for the
event-by-event correction of the light yield non-proportionality and for the
preferential selection of events with near-complete energy deposition, since
these will typically have high segment multiplicities.Comment: Accepted for publication in Nuclear Instruments and Methods in
Physics Research Section
Multichannel FPGA based MVT system for high precision time (20~ps~RMS) and charge measurement
In this article it is presented an FPGA based ulti-oltage hreshold
(MVT) system which allows of sampling fast signals ( ns rising and falling
edge) in both voltage and time domain. It is possible to achieve a precision of
time measurement of ps RMS and reconstruct charge of signals, using a
simple approach, with deviation from real value smaller than 10.
Utilization of the differential inputs of an FPGA chip as comparators together
with an implementation of a TDC inside an FPGA allowed us to achieve a compact
multi-channel system characterized by low power consumption and low production
costs. This paper describes realization and functioning of the system
comprising 192-channel TDC board and a four mezzanine cards which split
incoming signals and discriminate them. The boards have been used to validate a
newly developed Time-of-Flight Positron Emission Tomography system based on
plastic scintillators. The achieved full system time resolution of
(TOF) ps is by factor of two better with respect to the
current TOF-PET systems.Comment: Accepted for publication in JINST, 10 pages, 8 figure
Evaluating Rapid Application Development with Python for Heterogeneous Processor-based FPGAs
As modern FPGAs evolve to include more het- erogeneous processing elements,
such as ARM cores, it makes sense to consider these devices as processors first
and FPGA accelerators second. As such, the conventional FPGA develop- ment
environment must also adapt to support more software- like programming
functionality. While high-level synthesis tools can help reduce FPGA
development time, there still remains a large expertise gap in order to realize
highly performing implementations. At a system-level the skill set necessary to
integrate multiple custom IP hardware cores, interconnects, memory interfaces,
and now heterogeneous processing elements is complex. Rather than drive FPGA
development from the hardware up, we consider the impact of leveraging Python
to ac- celerate application development. Python offers highly optimized
libraries from an incredibly large developer community, yet is limited to the
performance of the hardware system. In this work we evaluate the impact of
using PYNQ, a Python development environment for application development on the
Xilinx Zynq devices, the performance implications, and bottlenecks associated
with it. We compare our results against existing C-based and hand-coded
implementations to better understand if Python can be the glue that binds
together software and hardware developers.Comment: To appear in 2017 IEEE 25th Annual International Symposium on
Field-Programmable Custom Computing Machines (FCCM'17
Optimization of multi-gigabit transceivers for high speed data communication links in HEP Experiments
The scheme of the data acquisition (DAQ) architecture in High Energy Physics
(HEP) experiments consist of data transport from the front-end electronics
(FEE) of the online detectors to the readout units (RU), which perform online
processing of the data, and then to the data storage for offline analysis. With
major upgrades of the Large Hadron Collider (LHC) experiments at CERN, the data
transmission rates in the DAQ systems are expected to reach a few TB/sec within
the next few years. These high rates are normally associated with the increase
in the high-frequency losses, which lead to distortion in the detected signal
and degradation of signal integrity. To address this, we have developed an
optimization technique of the multi-gigabit transceiver (MGT) and implemented
it on the state-of-the-art 20nm Arria-10 FPGA manufactured by Intel Inc. The
setup has been validated for three available high-speed data transmission
protocols, namely, GBT, TTC-PON and 10 Gbps Ethernet. The improvement in the
signal integrity is gauged by two metrics, the Bit Error Rate (BER) and the Eye
Diagram. It is observed that the technique improves the signal integrity and
reduces BER. The test results and the improvements in the metrics of signal
integrity for different link speeds are presented and discussed
A Monolithic Time Stretcher for Precision Time Recording
Identifying light mesons which contain only up/down quarks (pions) from those
containing a strange quark (kaons) over the typical meter length scales of a
particle physics detector requires instrumentation capable of measuring flight
times with a resolution on the order of 20ps. In the last few years a large
number of inexpensive, multi-channel Time-to-Digital Converter (TDC) chips have
become available. These devices typically have timing resolution performance in
the hundreds of ps regime. A technique is presented that is a monolithic
version of ``time stretcher'' solution adopted for the Belle Time-Of-Flight
system to address this gap between resolution need and intrinsic multi-hit TDC
performance.Comment: 9 pages, 15 figures, minor corrections made, to appear as JINST_008
Silicon Photomultipliers (SiPM) as novel photodetectors for PET
Next generation PET scanners should fulfill very high requirements in terms of spatial, energy and timing resolution. Modern scanner performances are inherently limited by the use of standard photomultiplier tubes. The use of Silicon Photomultipliers (SiPMs) is proposed for the construction of a 4D-PET module of 4.8×4.8 cm2 aimed to replace the standard PMT based PET block detector. The module will be based on a LYSO continuous crystal read on two faces by Silicon Photomultipliers. A high granularity detection surface made by SiPM matrices of 1.5 mm pitch will be used for the x–y photon hit position determination with submillimetric accuracy, while a low granularity surface constituted by 16 mm2 SiPM pixels will provide the fast timing information (t) that will be used to implement the Time of Flight technique (TOF). The spatial information collected by the two detector layers will be combined in order to measure the Depth of Interaction (DOI) of each event (z). The use of large area multi-pixel Silicon Photomultiplier (SiPM) detectors requires the development of a multichannel Data Acquisition system (DAQ) as well as of a dedicated front-end in order not to degrade the intrinsic detector capabilities and to manage many channels. The paper describes the progress made on the development of the proof of principle module under construction at the University of Pisa
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