CODA at Bates BLAST Data Acquisition

1. CODA at Bates BLAST Data Acquisition Karen Dow

2. The Bates Large Acceptance Spectrometer Toroid End View 8 Coils, Toroidal magnetic field, two sectors instrumented Top View Drift Chambers, Scintillators, Cerenkovs and Neutron Counters (not shown) BLAST is optimized for studying the spin structure of the nucleon and light nuclei, using polarized internal targets and a stored polarized electron beam. Karen Dow

3. Detectors Per Sector: • 16 Time-of-Flight scintillators with 2 phototubes each: ADC and TDC • 4 Cerenkov boxes: ADC and TDC • 4 Back Angle Time-of-Flight scintillators (BATs) with 2 phototubes each: ADC and TDC • 8 Ohio neutron counters (4m long by 10cm thick) with 2 phototubes each: ADC and TDC • 28 LADS neutron Counters (1.8m tall by 15 or 20cm thick) with 2 phototubes each: ADC and TDC • Drift chambers with 165 cells of 3 wires each, arranged in 3 chambers of 2 superlayers each (+- 5 degree stereo angle): drift chamber TDC (18 wires per track, nominally) • A total of 116 ADC, 116 TDC and 495 drift chamber TDC channels per sector Karen Dow

4. A Typical (e,e’p) event Karen Dow

5. Electronics • Analog splitter for phototube signals with passive delay for ADC • CAMAC for the programmable trigger (LeCroy and CAEN) • JLab Trigger Supervisor • SIS 3801 VME scalers; SIS 3610 input register for target status • PEC fixed delay for phototube TDC signals • In-house built VME modules for neutron counter discrimination, logic and delay • FASTBUS ADCs and TDCs (LeCroy 1881M, 1875A and 1877) • LeCroy 1458HP high voltage mainframes Karen Dow

6. History of CODA at Bates • Design goal for BLAST was to use off-the-shelf components, including DAQ software – less than 1FTE to support DAQ. • First used in 1998 with CAMAC for early tests of detector rates with a stored electron beam. CES8210 for VME-CAMAC interface. Triggered on interrupts from LAM in a BiRa LAMPF trigger module. • Used in 2000 with one FASTBUS crate and SFI front-panel triggers for tests of BLAST prototype detectors. • Used in 2001 in detector test facility to characterize time-of-flight scintillators, Cerenkovs. One FASTBUS crate, SFI front-panel triggers. • BLAST commissioning began in 2002 with two FASTBUS crates, Trigger Supervisor. • Level 2 trigger implemented fall of 2003. • Reliably taking production data. Karen Dow

7. DAQ Components FASTBUS L MVME162 Beam parameters EB dblast07 FASTBUS R MVME162 ET ER disk visual_scal EPICS server dblast08 VME TS MVME162 Target Control HV gui (EPICS) elog VME Scalers MVME162 CES8210 trigger gui CAMAC Trigger Compton Polarimeter onlineGui (Root) dblast09 dblast13 Karen Dow

8. Some Information • Event size about 1.6kByte – keep all ADC pedestals for time walk correction on leading edge discriminators. • 8 different event types, loosely associated with physics. Some types are heavily prescaled. • 4 configurations (level 1 triggers; level 2 triggers; non-strobed mode; cosmics) • Level 1 trigger rate about 20 events/mA, running now at a ring fill current of 150mA. Second level trigger based on wire chamber hits takes us down to a bit over 1event/mA. • About 15-20% dead at 150mA. Plan to implement buffering in ADCs and TDCs in the next two weeks. Then we expect to have basically no dead time until we hit an event rate of about 330 events/sec, when we hit the Ethernet bandwidth. We don’t anticipate rates that high, so we don’t plan to upgrade to PPCs. Experiment ends 12/04. Karen Dow

9. Summary • Bates has been working with CODA for 7 years – first with CAMAC, then with FASTBUS. • Reliably taking data at 320kB/s (typical), have run as high as 550kB/s. • Accomplished with a small manpower investment (about 3 man-years). Karen Dow

10. Electronic Logbook – Beginning and End of Run Karen Dow

11. onlineGUI for raw data monitoring Karen Dow

12. EPICS High Voltage GUI Karen Dow

13. Visual Scalers Karen Dow

14. Trigger GUI Karen Dow