Karen DowJune 7, 2004

CODA at BatesBLAST Data Acquisition

June 7, 2004 Karen Dow

The Bates Large Acceptance Spectrometer Toroid

End View8 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 polarizedinternal targets and a stored polarized electron beam.

June 7, 2004 Karen Dow

Detectors

• 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

Per Sector:

June 7, 2004 Karen Dow

A Typical (e,e’p) event

June 7, 2004 Karen Dow

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

June 7, 2004 Karen Dow

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.

June 7, 2004 Karen Dow

DAQ Components

FASTBUS LMVME162

FASTBUS RMVME162

VME TSMVME162

EB

ET

VME ScalersMVME162CES8210

CAMACTrigger

visual_scal

trigger gui

ER disk

dblast07

EPICSserver

dblast09

ComptonPolarimeter

dblast13

onlineGui(Root)

HV gui(EPICS)

elog

dblast08

TargetControl

Beamparameters

June 7, 2004 Karen Dow

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.

June 7, 2004 Karen Dow

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).

June 7, 2004 Karen Dow

Electronic Logbook – Beginning and End of Run

June 7, 2004 Karen Dow

onlineGUI for raw data monitoring

June 7, 2004 Karen Dow

EPICS High Voltage GUI

June 7, 2004 Karen Dow

Visual Scalers

June 7, 2004 Karen Dow

Trigger GUI