# Presentation: 804057

## Week of November 18 to November 24 D0 Summary

- Delivered luminosity and operating efficiency
- Delivered: 3.7pb-1
- Recorded: 2.7pb-1 (72%)
- Data taking efficiency
- no major hardware/software problems
- experienced 3 ~one hour downtime periods which affected efficiency during this short week
- Number of events collected
- 7mln events
- Accelerator halo
- reasonable

- Dmitri Denisov

## Data Taking and Triggering

- Running physics trigger list 9.3 for the last two weeks
- stable
- designed for luminosity in the range (5-50)1030
- optimized for high Pt data collection and physics data sample for Winter Conferences
- Trigger rates guidelines are limited by trigger/DAQ systems stability
- L1 trigger ~0.5kHz
- L2 trigger 0.2-0.3kHz
- L3 trigger (to tape) ~50 Hz
- Currently most serious issues limiting our efficiency and trigger rates
- muon readout
- mini-drift tubes issue is understood, plan to resolve within a week
- PDT problems are not understood yet
- calorimeter readout
- starts to limit operating efficiency at Level 2 rate of ~0.5kHz
- Longer term trigger rate plans
- by January shutdown run at rates close to Run II specs for Level 2(1kHz) and Level 3(50Hz) triggers
- if PDT and Calorimeter issues are resolved
- Level 1 trigger output rate expected to be at ~2kHz after January shutdown (limited by Level 2 trigger processing power)
- expect ~ doubling L1 trigger accept rate with beta commissioning - Summer 2003

- Dmitri Denisov

## Pbar Kicker Prefire on 11.22.02 

- At 14:48 on 11.22.02 store was lost due to pbar kicker pre-fire
- This accident affected D0 silicon in the following way
- tripped ~25% of HV channels (as well as some muon channels)
- integrated dose of ~100rads
- pulled beam abort due to high rate losses on the pbar side of the detector
- peak rate was 60rads/sec with abort limit set at 12rads/sec
- only pbar side BLMs detected high dose rate
- After irradiation
- D0 was able to reset all HV trips
- After reset and re-download all HDIs (those which were in good shape before the accident) are working properly
- This was the first radiation level related HV trip in D0 silicon over last ~8 months
- task force to understand reasons for pre-fires should be created
- experiments should be informed about status and plans
- Collecting data with silicon in readout since Saturday

- Dmitri Denisov

## Summary

- D0 experiment is progressing well with physics data taking
- trigger list 9.3 is running on-line
- 7 mln events collected last week
- D0 weekly data taking efficiency is steady around 75%
- no major software/hardware problems
- running in the “stability” region of the L1/L2 rates plot
- in process of attacking (currently) most serious  issues
- muon MDT loss of sync and muon PDT DSP software crashes
- other rate/efficiency limiting issues are under studies as well
- downtime is on the level of ~7% for the week
- Starting detailed planning of the January shutdown
- plan to perform large scale detector “opening”
- including parts of the muon system
- will gain access to the central area of the detector
- minor repairs of the silicon electronics
- access to TLDs with accurate measure of silicon irradiation
- At this moment have no access request and plan for data taking over Thanksgiving week

- Dmitri Denisov