Bulletin of the American Physical Society
2011 Fall Meeting of the APS Division of Nuclear Physics
Volume 56, Number 12
Wednesday–Saturday, October 26–29, 2011; East Lansing, Michigan
Session 1WB: Workshop on Advanced Digital Signal Processing Techniques in Nuclear Science I |
Hide Abstracts |
Chair: Sean Liddick, Michigan State University Room: 104AB |
Wednesday, October 26, 2011 8:30AM - 9:00AM |
1WB.00001: Gamma ray energy tracking in GRETINA Invited Speaker: I.Y. Lee The next generation of stable and exotic beam accelerators will provide physics opportunities to study nuclei farther away from the line of stability. However, these experiments will be more demanding on instrumentation performance. These come from the lower production rate for more exotic beams, worse beam impurities, and large beam velocity from the fragmentation and inverse reactions. Gamma-ray spectroscopy will be one of the most effective tools to study exotic nuclei. However, to fully exploit the physics reach provided by these new facilities, better gamma-ray detector will be needed. In the last 10 years, a new concept, gamma-ray energy tracking array, was developed. Tracking arrays will increase the detection sensitivity by factors of several hundred compared to current arrays used in nuclear physics research. Particularly, the capability of reconstructing the position of the interaction with millimeters resolution is needed to correct the Doppler broadening of gamma rays emitted from high velocity nuclei. GRETINA is a gamma-ray tracking array which uses 28 Ge crystals, each with 36 segments, to cover $\raise.5ex\hbox{$\scriptstyle 1$}\kern-.1em/ \kern-.15em\lower.25ex\hbox{$\scriptstyle 4$} $ of the 4$\pi $ solid angle. The gamma ray tracking technique requires detailed pulse shape information from each of the segments. These pulses are digitized using 14-bit 100 MHz flash ADCs, and digital signal analysis algorithms implemented in the on-board FPGAs provides energy, time and selection of pulse traces. A digital trigger system, provided flexible trigger functions including a fast trigger output, and also allows complicated trigger decisions to be made up to 20 microseconds. Further analyzed, carried out in a computer cluster, determine the energy, time, and three-dimensional positions of all gamma-ray interactions in the array. This information is then utilized, together with the characteristics of Compton scattering and pair-production processes, to track the scattering sequences of the gamma rays. GRETINA construction is completed in March 2011, and extensive engineering runs were carried out using radioactive sources, and beams from the 88-Inch Cyclotron at LBNL. The data obtained will be used to optimize its performance. Then the first scientific campaign will start in March 2012 at NSCL MSU. [Preview Abstract] |
Wednesday, October 26, 2011 9:00AM - 9:30AM |
1WB.00002: TBD Invited Speaker: W. Stoeffl |
Wednesday, October 26, 2011 9:30AM - 10:00AM |
1WB.00003: The Upgrade Path From Legacy VME to VXS Dual Star Connectivity For Large Scale Data Acquisition and Trigger Systems Invited Speaker: Chris Cuevas New instrumentation modules have been designed by Jefferson Lab that take advantage of the higher performance and elegant backplane connectivity of the VITA 41 standard of VXS. These new modules are required to meet the 200KHz trigger rates envisioned for the 12GeV experimental program. Upgrading legacy VME designs to the high speed gigabit serial extensions that VXS offers, comes with significant challenges, including electronic engineering design, plus firmware and software development issues. This paper will detail our system design approach including the critical system requirement stages, and explain the pipeline design techniques and selection criteria for the FPGA that require embedded Gigabit serial transceivers. The entire trigger system is synchronous and operates at 250MHz clock with synchronization signals, and the global trigger signals distributed to each front end readout crate via the second switch slot in the 21 slot VXS backplane.. The readout of the buffered detector signals relies on 2eSST over the standard VME64x path at $>$200MB/s. We have achieved 20Gb/s transfer rate of trigger information within one VXS crate and will present results using production modules in a two crate test configuration with both VXS crates fully populated. The VXS trigger modules that reside in the front end crates, will be ready for production orders by the end of the fiscal year. VXS Global trigger modules are in the design stage now, and will be complete to meet the installation schedule for the 12GeV Physics program. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700