# Presentation: 426365

## DØ Summary - Week of 2002  October 7-13

**Luminosity & operating efficiency*********
**Delivered: 6.5 pb****-1**
**Recorded: 3.6 pb****-1**** **
***    ******(~56% data taking eff.)***
**9.3 million physics events**
**15.2 hours of downtime****               *****(see next slide)***
**Accelerator halo**
**No problems aside from Store 1839**
****Numbers for Oct 9******th****** are incorrect & will be revised, but it affects weekly report***

## Data Taking Statistics**Preliminary**

**Significant sources of data taking downtime**
**2.7 hrs:  Beginning of Store 1839 (miscogging of pbars)**
**2.3 hrs:  L2 Alpha Crashes **
**Six times Wed-Fri, always during beam!**
**2 hrs:  Beginning of Store 1843 (L3/DAQ, TFW, L2 Global?)**
**After 2 hrs w/several experts, the problem mysteriously disappeared**
**1 hr:  End of Store 1839 (see slides #4,5)**
**0.8 hrs:  SMT HV trips**
**Ramping at the beginning of ~50% of stores**

## Best Days by Recorded Luminosity

**17 days with Rec. Lumi>0.5 pb****-1**

## Results of DAQ Rate Test

**Requested End of Store studies be delayed from 08:00 to 09:00 on Friday Oct 11****th**
**Store 1839, Lumi~9E30**
**Called in experts for all systems for one hour**
**Required full detector readout, with all HV on to simulate real data taking**
**Used a real set of triggers which utilized L2 & L3 tools for rejection **

**Reached L1 ~ 1450 Hz**
**System was stable but the global FEB was >10%**
**Too high of a ‘prescale’**
**Reached L2 ~ 660 Hz**
**Muon & L2 crates oscillated in FEB**
**SMT L1 queues were full**
**Waiting for L2 accepts**
**Bottom Line**
**Stable data taking with L1/L2 ~ 1250/350 Hz**
**Still restricted to L3<60 Hz**

## Progression of Rate

**1****st**** week of July:  L1/L2/L3 ~ 200/70/30 Hz**
**Created DAQ Task Force**
**Solved stability problems in Aug/Sept 2002**
**Muon Readout Errors – firmware upgrade**
**L2 Muon out-of-synch – bug fixes, new tables**
**L3 back pressure – added 31 new farm nodes**
**Trigger tables – reallocated bandwidth to priority physics, tuned prescales to maximize L1/L2**
**Friday Oct 11****th**** – Store 1841**
**First Run - Begin Lumi = 29.53E30. **
**Initial peak L1/L2/L3 rates ~ 900/260/52 Hz. **
**Second Run - Begin Lumi = 25.81E30**
**Initial peak L1/L2/L3 rates ~ 1000/285/55 Hz. **
**First Run IIa global physics run with L1 > 1 kHz!**

**Tweaked **
**Prescales**

## Muon MDT HV ProblemRequires Access

**Affects entire octant of our North B-layer**
**~150 MDT tubes **
**Requested 1 hour access between store termination & beam studies today to locate the source of problem**
**Check many HV cable connections in detector**
**Requires ~1 hour to fully investigate **
**More details after CA**

**Need 8-12 hour Access**
**Move North B-layer pixel plane to access B-layer MDTs**
**>1 yr since our crew last did this kind of job **
**review diagrams & procedures **
**Scaffolding **
**Octant 1 – upper half**
**Postpone until scheduled access**

## Plans for Upcoming Week

**Software & Network upgrades to online system during beam studies**
**Focus on data taking stability **
**More experts at the beginning of each store**
**Minimize changes to detector systems**
**Work restricted to repairs & maintenance**
**No major problems *****(except for MDT HV)***
**Will disable channels & continue to run until a **_**Scheduled**_** Access opportunity arises**