AMANDA TWR (Transient Waveform Recorders) DAQ 2003/2004 & 2004/2005

Wolfgang Wagner (wagner@uni-wuppertal.de)Steve Barwick(barwick@cosmic.ps.uci.edu)

TWR ELECTRONICS WITH 6 VME CRATES CONTAINING 72 TWR MODULES

MENU: What is new in 2004/2005? PRELIMINARY TWR WEBPAGE IN DORTMUND What is new in 2003/2004? Hardware upgrades Software upgrades Quickguide for TWR Operations System Overview and Data Handling Procedures Future Plans and Initial Test of Software Trigger Architecture Hardware Manuals and Documentation: (Cable Maps, Channel Maps, Offset Times, Thresholds, etc) Software Manuals and Documentation: (Eventually Waveform Visualization, Merging Programs, Filtering, Raw Data Reader, etc.) Older References List of Spares for TWR04 TWR simulation page(coming) Specialized Data Collected During Summer 03/04

• The Transient Waveform Recorder System (TWR) is designed to extend the integrated dynamic range of each OM in AMANDA-II by approximately a factor of 100, relative to the standard AMANDA DAQ. The TWR system can handle the normal muon trigger rates with virtually no dead time. The "discriminator" thresholds for each channel can be set to values significantly lower than 50mV, the lowest operational values available in the DMAD. This too helps to improve performance by making 1 pe detection more efficient. The added capability should improve the energy resolution and background rejection for high energy phenomena, including the search for EHE nu's in the downgoing direction, the search for high energy cascades, and GRBs. It should also help to improve the angular resolution of higher energy muons (muons that cross the array with an excess of 100 TeV). The TWR DAQ suppresses waveforms with OM signals and extracts waveform "features" for additional compression.  Additional goals can be found in 

• In 2003/2004, we had two primary objectives.  The first was to increase the data throughput so that the TWR system can trigger at much higher rates than in the previous year, and the second was to investigate possible hardware solutions to allow the formation of software triggers.  The system overview describes the system and changes to the TWR system in 2004.   The TWR04 is now reading at a trigger rate of 150 Hz ( and majority logic M=18), which is approximately double the rate (~90Hz) of the previous year.  Simulations show that detector sensitivity for physics objectives with low backgrounds can be doubled if the trigger rate is doubled.  Low background science objectives include the search for neutrinos from GRBs, the search for EHE diffuse neutrinos, and episodic emission from point sources. In essence, the AMANDA-II detector is 2x better than it was last year for these science goals.  The TWR readout is capable of 230 Hz of deadtimeless readout, but data traffic is prohibative at this time.  

• Last year, we demonstrated that the TWR system achieves an integrated dynamic range of 5000 photoelectrons by including the afterpulses from the initial burst of cherenkov light.   Timo adjusted the delay so  that there is better uniformity in the readout so that every channel provides ~7us for the observation of afterpulses. The second objective was to initiate tests of the hardware for software trigger development.  Wolfgang tested new FPGA firmware from SIS, the company that supplies the TWR modules.  The new firmware performs feature extraction in the TWR itself, prior to the readout by the DSP, so the VME bus can handle the continuous stream of waveform fragments and ultimately build an event within one or more cpus.

• Hardware and Firmware upgrades in 2003/2004:  The RIO3 VME cpu (300MHz) in the master crate was replaced by a VME to PCI bridge, which connects to a Compac DL380 dual cpu, running at 1.4 GHz.  The local hard disk capacity was increased to 140GB, which provides local storage for about 3 days of data.   Instead of performing the feature extraction within the RIO3 cpu, the current system uses new firmware, written by Wolfgang Wagner,  in the DSP (digital signal processor) to extract features in the waveform.  Therefore, the PC computer can spend more of its resources building events instead of extracting features in the waveforms.  During 2003, we developed more efficient requirements for the waveform extraction routines so that the bytes/event decreased by a factor of ~50% relative to TWR03.  The waveform extraction routine was streamlined to fit in the DSP memory limitations.    The MBS software used in TWR03 to readout the data did not support the VME-PCI bridge, thus new software was written to readout the data and write to local disk.  Consequently, TWR04 operation and interaction with the muon-DAQ is more straightforward than TWR03. Operators can add one sentence comments to the log file (which contains error information diagnostics as well), so users can describe the purpose of the run.  We also made additional improvements to the TWR04 system.  First, the trigger distribution is distributed via the VME backplane rather than the logistically cumbersome NIM fanouts. It also improves long term reliability.   We increased the number of active channels to 597, up from 576 in TWR03.  This now includes all functioning OMs with the exception of those on string 17.  We have a more complete stock of spare components and replacement modules compared to last year.  Timo M. adjusted the programmable trigger delay in the TWR system so  that there is better uniformity in the readout. Therefore, every channel provides ~7us for the observation of afterpulses.

•  Software and Data Handling upgrades in 2003/2004:   The prodigious amount of data generated by the TWR system strained the data handling procedures in 2003.  Therefore several upgrades to the data handling procedures were implemented this summer season.  The TWR merging software was extensively re-written to alleviate data traffic on the network in BOS.  The TWR data file names now contain timing information that indicates the start and termination time of each file.  Instead of reading the whole file to determine this information, the merger software has quick access to this critical information.  The merger first selects only the high priority events ( this year, high priority events are selected when the number of OMs with waveforms is larger than 120) to reduce the data traffic generated by the TWR. TWR-specific monitor files are produced by the initial filtering program which is available for display by the AMANDA monitoring software written by Jens Ahrens.  The merged data format has been changed to include the baseline level of each fragment, which gets appended to the end of every fragment.  Finally, the raw TWR data is automatically compressed by the SDLT tape drive, so no cpu-intensive gzipping is required.   While not specific to TWR, a new batch queuing system was installed this season so that filtering, merging, and archiving are distributed to all available computers in BOS.  Therefore, computer resources are more fully utilized and TWR specific processing is more easily accomplished.  At this point, the computer resources are sufficient to handle all of the data related tasks in 2004.  There are sufficient SDLTs to provide 1 complete record of all data acquired in 2004.
  

• A summary of the performance characteristics of TWR04 
  • 597 OM channels (nearly all usable channels - no OMs on string 17)
  • 6 VME crates containing 14 TWR, 1 DSP, 1 VME to VME optical bridge
  • M=18 trigger from DMAD (no string, no SPASE;  we expect to include multiple trigger next season as a fallback to software trigger)
  • Trigger rate ~ 150 Hz, virtually no dead time
  • Data rate - 68GB/day uncompressed, 34 GB/day with hardware compression on the SDLT drive
  • TWR data archived to SDLTs (~100 GB/tape)
  • High multiplicity merged data sent via satellite (1 GB/day);  N_OM in event >120
  • Pre-scaled M=24 merged data sent via satellite ( 2.5% of the M=24 triggers)
  • 1 raw data file containing M=18 triggers
    
    
  Steve Barwick 
  Last modified: Feb 20 2004