Radiation protection for the D0SMT is provided by a set of 8 beams division ion chambers (BLMs); four each located upstream (south) and downstream (north) of the IP.  The current signals are converted to voltage in the TeV log amplifier chassis in M303.  The chassis also provides HV to bias the ion chambers. The eight analog signals are sent to four C335 CAMAC modules in the Tevatron rack on DAB1.  The 335 module converts the voltage signals to an analog dose rate value and compares that value to abort and alarm thresholds downloaded from ACNET.  Abort signals are summed in the C337 module.  C337 Alarms are usually set to half the abort value and are read via CAMAC. 

The C336 module, which is joined to the C335, takes the ADC output at 5 khz, subtracts an offset, and  uses a look up table to convert the logarithmic voltage back to a linear rads/sec rate.  The module adds to the radiation sums if the resulting count is above a threshold.  This rate is integrated (usually over the store) to provide a total dose.  The module also provides a one minute rolling sum of radiation. The rolling sum is used to provide an audible alarm in the D0 control room via another input to the C337.  Please note that:

• The beam is only automatically aborted by the rate in the C335
• Audible alarms are generated by aborts and one minute rolling sums
• ACNET alarms are generated by one minute rolling sums, rate, and total integrals exceeding thresholds

Radiation protection system D0 Note.

D0 Radiation Protection Procedure.

Details on ACNET devices.

Some e-mail notes on BLM characteristics.

How to use the Lumberjack plotter.
 

Plotting data from the Finger Archiver.

Logic used to remove SMT readout noise.

BLM Calibration study.

Early BLM electronics study

Dose estimate based on leakage currents.

Luminosity and Halo contributions to silicon dose.

Radiation protection tutorial.