Data Acquisition Scheme for Nuclear Physics Experiments

The data acquistion set up for nuclear physics experiments at ELBE is based on a mixed synchronized readout of various digitizers in different form factors (crates). The central processor unit (CES CPU) resides in a VME crate and runs the readout software MBS developped at GSI. The operating system is Lynx OS. Readout procedures for each component had been developped and tested, and a simple CAMAC ESONE library has been implemented. CAMAC readout is performed using CAMAC crate controllers (WIENER CC32) connected to the VME CAMAC branch driver (WIENER VC32) via standard CSCI cables. CAMAC readout speed is limited to 1 MWords/s but can be increased for suitable modules (like Phillips peak sensing ADC). For fast list-mode data acquisition a FERA-Bus readout with 10 MWords/s is implemented. The FERA-Bus is connected to VME via a high speed FIFO (SIS FIFO). Data are taped using either 8 mm video tape drives (EXABYTE) or DLT tape drives. Data throughput reaches tape bandwidth at 1.5 MByte/s.
MBS readout scheme

Synchronous readout for list-mode data:

  • VME-based trigger module (GSI TRIGGER) allows for multiple hardware trigger conditions and local event counter.
  • VME-based peak-sensing analog-digital converters enabling readout of up to 80 channels of silicon detector electronics of RoSiB (CAEN ADC).
  • CAMAC-based charge-sensitive analog-digital converters with time-to-charge converters enabling readout of up to 32 channels of HPGe timing information (LRS TFC + LRS QDC).
  • CAMAC-based interfaces for peak-sensing analog-digital converters enabling readout of up to 11 channels of HPGe energy information (GIE NFI).

Asynchronous readout for single spectra and scaler data:

  • CAMAC-based peak-sensing analog-digital converters enabling readout of 4 channels Si(Li) energy information from deuteron breakup. (ORT ADC + ORT HIST)
  • CAMAC-based scaler modules (LRS SCAL).

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  IKH 17/12/2001 © Andreas Wagner