# Presentation: 775604

## Week of July 16 to July 22 D0 Summary

- Delivered luminosity and operating efficiency
- Delivered: 1.6pb-1
- Recorded: 1.0pb-1 (~65%)
- Major reasons for in-efficiency
- Loss of ~6 hours due to Level 1 calorimeter trigger problem during Sunday owl shift
- Muon readout stability
- CFT/SMT downloading issues
- Stable running at twice higher Level 1 and Level 2 accept rates
- ~0.2kHz out of Level 1 trigger
- ~140Hz out of Level 2 trigger
- ~50Hz to tape
- Last week operational issues
- Loss of LVPS in the muon system
- replaced on Sunday access
- Commissioning of fiber tracker trigger
- Halo rates are back to stable values

- Dmitri Denisov

## Week of July 15 to July 22 D0 Operations

- Luminosity detector
- Stable
- Silicon detector
- Power supplies are running well
- Quite time used for calibrations
- Calorimeter
- Noisy trigger towers and cells masking
- Calibration of Level 1 trigger energy scale
- Muon
- loss of serial link communication every ~10minutes
- limiting Level 3 data transfer rate
- related to running in multibuffer mode
- experts are working - more diagnostic tools are needed
- Forward proton detector
- inserting pots during most stores
- request for tunnel access to
- fix failures
- connect new electronics/hardware

- Dmitri Denisov

## D0 Trigger 

- Trigger framework
- Existing prescaler logic could report mis-measured luminosity for prescaled triggers
- Plan on how to resolve this problem is developed
- L1 trigger
- Fiber tracker (CTT) trigger
- Implementation for muon triggering is delayed due to higher then specified trigger decision time
- Different options of resolving this issue are discussed by experts
- Estimated delay is ~6weeks
- Calorimeter trigger
- Debug recently achieved eta coverage up to 2.4
- Dead and noisy towers, calibration
- Missing Et
- Extend eta coverage
- Muon trigger
- Optimize new trigger terms based on scintillator and wire detectors
- Re-establish data vs trigger simulator comparison
- Attempt to shave 132ns from FPGA logic
- To accommodate CTT trigger delay

- Dmitri Denisov

## D0 Trigger 

**Level 2 trigger**
**Increase processing bandwidth from current ~0.5kHz **
**Code speedup/max_opt:                  1-2 kHz**
**Multiple Alphas/Betas in crate          >2 kHz?**
**Silicon track trigger**
**In progress of installation**
**Expect beam commissioning later this year (fiber tracker trigger needed)**
**Fiber tracker**
**Waiting for inputs – expected in September**
**Calorimeter trigger**
**Running on-line (/eta/<0.8 for now)**
**Requires better understanding of efficiency, cuts, rejection**
**Muon trigger**
**Well developed: single muon, di-muon**
**Resolving problems with synhronization of signals coming from hundreds of front-ends**
**Detailed monitoring of the inputs is needed**
**Algorithms optimization (geometry for P****t**** cut, etc.) is in progress**

- Dmitri Denisov

## D0 Trigger

- Level 3 trigger
- Running on-line for quite a while
- Development of fast and efficient algorithms with good rejection is driving the schedule
- Tracking Level 3 is coming on-line this week
- Improve electron and muon rejection
- Vertex for missing Et resolution improvement
- Calorimeter is one of the most advanced systems
- Efficiently filtering jets and em objects
- Coming in p12: missing Et, non-linearity corrections, hot cell killer
- Muon
- Filtering on limited sub-set of muon triggers
- Technical issues with muon geometry, efficiency to be better understood
- Level 3 trigger basic philosophy
-  Develop as much as possible inclusive single e, mu, tau, jet filters
- Combine tools into di-muon, muon+jet, etc. filters

- Dmitri Denisov

## DAQ

- Currently could utilize new DAQ system rate capabilities in a limited way due to complex system of distributed readout and front-end crates
- Multi-buffering operation in tracking crates just arrived
- Correct “tick and turn” operation to be verified
- With estimated DAQ rate capability in the range of ~1kHz we are currently limited to ~140Hz for reliable on-line operation
- Current most serious problem is loss of synhronization in muon scintillator crates
- Every ~10 minutes at 140Hz
- There are other concerns on the horizon
- Tracking crates  front-end busy fraction at 140Hz is ~4%
- DAQ rate “task force” has been organized (chaired by Ron Lipton)
- Very well defined goal
- Bring experts from different sub-systems together to resolve problems preventing us from running at full DAQ capabilities

- Dmitri Denisov

## On-line System and Controls

- Key system for data handling/transfer and on-line data quality monitoring
- Run II design rate of writing data to tapes at 50Hz has been achieved
- Operations
- Significant Event System (alarms)
- important issue for high quality data collection
- active participation from detector/trigger groups is required
- improve support of Examines
- Applications
- deploy run configuration/quality database
- introduce global DAQ monitor application

- Dmitri Denisov

## D0 Operating Efficiency

- Goals
- From Run I experience
- ~190pb-1 delivered ~120pb-1 recorded (~60%, Main ring vetoes, etc.)
- Should do better in Run II –> 90%
- Moving target
- Major reasons of luminosity loss are changing as more systems come on-line
- What was a concern  a few months/weeks ago is replaced by new “enemies”
- Steady increase in operating efficiency during February/March – “steady state” operation
- Recent numbers
- ~60% for the last ~2 months (lower before)
- ~75% last week (after implementation of mutli-buffer readout)

- Dmitri Denisov

## D0 Operating Efficiency

- Major components of the inefficiency
- Dead time
- Sub-system is setting busy signal due to low bandwidth: L1, L2, L3, DAQ
- Adjustable and can be set at almost any value by adjusting trigger rates
- Due to lack of multi-buffering in tracking crates had to accept relatively large L1 front-end-busy fraction (~20%) to collect decent data sample before June shutdown
- Currently running at about 4% front-end-busy fraction (140Hz readout rate)
- Downtime
- Data collection is stopped (or could not be started) due to failure of a specific component (or components)
- Currently issues are
- Muon scintillator front-end crates errors
- High Voltage trips
- Redownloading of “problematic” crates
- Begin/end runs
- Operator errors
- Commissioning activities (prescales selection, trigger studies,...)
- Experts are working on resolving all of the above issues
- Plan to keep efficiency at the ~70% level while new sub-systems are introduced
- Our steady state operating efficiency should be in the range of ~90%
- Reachable – D0 had ~85% operating efficiency during some of the recent stores

- Dmitri Denisov

## Summary

- D0 is progressing well with collecting data and finishing commissioning of trigger and readout systems
- No serious short term problems with detector, trigger, DAQ
- D0 will be showing at ICHEP02 for the first time physics results using Run II data
- W and Z production cross sections and ratio at 2TeV
- b lifetime
- several limits for new phenomena searches
- A summary of the most recent results from D0 will be presented at a W&C seminar on Friday, July 26

- Dmitri Denisov