Speaker
Dr
robert knapik
(University of Pennsylvania)
Description
The SNO+ experiment is designed to explore several topics in neutrino physics,
including neutrinoless double beta decay and low energy solar neutrinos.
SNO+ uses the existing Sudbury Neutrino Observatory (SNO), with the heavy water
target replaced with liquid scintillator. Only a few additional modifications
are needed to transition from SNO to SNO+, but one of these will be an upgrade
to the electronics to handle the higher rates expected with scintillation light
as compared to Cherenkov light. The primary upgrades are aimed at increasing
the bandwidth for reading data from the front end electronics crates, and to
the trigger system to allow for higher analog currents. For SNO, each of the
19 front-end crates digitized and recorded the PMT signals but data could only
be read out one crate at a time. With the upgrade to the new electronics, each
of the 19 crates will autonomously push data to a central data acquisition
computer, yielding at least a factor of 19 times more bandwidth. The
autonomous readout is achieved with a field programmable gate array (FPGA) with
an embedded processor. Inside the FPGA fabric a simple state machine using
VHDL is configured to pull data across the VME-like bus of each crate and store
the digitized PMT signals in a local memory buffer. A small C program, making
use of open source Light Weight IP (LWIP) libraries, is run directly on the
hardware (no operating system) to send the data via TCP/IP to the central data
acquisition computer. The hybrid combination of `high-level' C code and
`low-level' VHDL state machine is a cost effective and flexible solution for
reading out individual front end crates.
Primary author
Dr
robert knapik
(University of Pennsylvania)
Co-authors
Mr
Richard Bonventre
(University of Pennsylvania)
Mr
Timothy Shokair
(University of Pennsylvania)
