# Presentation: 233783

## DØ Summary - Week of 2002 September 30 – October 6

**Luminosity & operating efficiency**
**Delivered: 3.6 pb****-1**
**Recorded: 2.4 pb****-1**** (~66%)**
**5.9 million physics events to tape**
**4.7 hours of downtime**
**Issues caused >20 min downtime**
**Muon PDT readout problems**
**Controlled Accesses: 15 m on Oct 4 & 20 m on Oct 6 to power cycle crate**
**Special Runs**
**Study muon detection efficiency**
**Study L2 CAL Jet Algorithm**
**Tevatron Scraping (Oct 4 owl shift)**
**Accelerator halo**
**Ok at beginning of store, but Pbar rates steadily rise within ~30 min**
**Spikes in 1****st**** hour of Stores**
**1808 (Oct 2 beginning eve shift)**
**1823 (Oct 4 beginning owl shift)**
**1824 (Oct 4 end day shift)**

## Data Taking Statistics**Preliminary**

**Total Data Taking Efficiency ******** 65.5%**
**325.7 nb****-1**** or 9.0% Lost due to ****Downtime**** **
**1209.5 nb****-1**** or 33.4% Lost due to ****Deadtime**
**Decorrelated (L2/L3/COOR Disables)**
**Correlated (FEB, SkipNextN)**
**38.9 nb****-1**** or 1.1% Lost at L2/L3**
** ****5876 k Events from Physics Runs recorded to tape **
**global_CMT-8.30:  1924 events through Store 1823**
**global_CMT-8.40:  3952 events from late day shift Oct 4**

**Still developing tools to understand all the sources of deadtime.**

## Best Days by Recorded Luminosity

## Calorimeter Preamp Cooling

## Replacement of Cooling Fans

**Reminder:  Week of Sep 23****rd**** D0 lost cooling in one of the Calorimeter preamp boxes**
**Temperature of the cooling air increased from 40°C to 69°C**
**Affected ~4% of calorimeter channels  ******** 12% of central calorimeter channels**
**We requested Supervised Access for Wed Oct 2 of 12-16 hours**
**4 hours each to open and close 1,000 tons muon magnets**
**4-8 hours to disassemble  box and replace failed fan(s)**
**Began SA at 04:30; South & East EF Open at 06:30**
**Closed detector from 14:30-16:30**
**Search & Secured by 19:00**

**Each Fanout Box has one large fan & two smaller fans near the heat exchanger**
**Large fan was dead **
** ****black dust in surrounding area**
**Probably the source of mysterious VESDA alarm in the recent past**
**Smaller fan mounted on the heat exchanger also dead **
**We think it failed after the larger fan**
**Overworked due to large fan failure**
**Replaced other small fan as a precaution**
**Exchangers & fans built as one “unit”**
**Small fans were tricky & we were missing a special screw & nut**
**Work delayed by 1.5 hours by special trip into Chicago**

## Calorimeter Preamp Fans

**Postmortem on large fan**
**Windings opened up – likely a manufacturer defect**
**Both smaller fans were bushing fans**
**Fans were dry and could not turn!**
**We had ordered ball bearing fans**
**Manufacturer sent the wrong fans**
**They were labelled correctly, but the labels were not visible because of the casing**
**All Calorimeter preamp cooling fans were procured & assembled using Columbia Univ. base grant money**
**There are 72 total fans**
**24 large & 48 small**
**L10 = 85k hours for small fans & **
**              ****55k hours for large ones**

**Fanout box put constraints on size and number of fans**
**Maximally push air through heat exchanger in rectangular volume**
**We may simply need to replace ALL fans every year as a preventative measure**
**Assuming shutdown > 1 week**
**New fans have been ordered**
**Still looking through the archiver**
**Looking at a step function in the temperature**
**Correlate to VESDA alarm(s)?**

## Other System Work

**30 New L3 farm nodes installed on Sat Oct 5****th**
**Double processing power!**
**This permits us to significantly raise our L2 output rate**
**Back pressure from farms would deny L3 accepts**
**Increase our L3 rejection on single muons **
**New online Linux PCs & flat screen monitors to be installed **
**Substantial increase in CPU & Memory**
**Many old nodes are overloaded**

**FPD Tunnel Access during Wed Shutdown**
**Installed 6 new TLDS**
**Previous TLD readings from 10 days in Aug (in REM)**
**L0 (lime glass) tubes sensitive to levels > 10****8 ****REM**
**MAPMTS (Borosilicate window) 10% loss in transmission at  levels > 10****5 ****REM**
**Helium levels are an issue (~1000 ppm).  May need special tunnel access to install air hoses to blow fresh air.**

## New Trigger List

**global_CMT-8.40 – Store 1824 on Fri Oct 4****th**** end of day shift**
**L1: Calorimeter EM and JET tower triggers and MUON triggers based on central and forward muon scintillator detectors. **
**L2: EM, JET, MUON, and angular separation filters. **
**L3: Electron, Jet, Tau and Muon filters, some of which use the central tracking systems. **
**Changes from global_CMT-8.30:**** **
**Muon events at L3 – Changed from mark & pass of 1 to pass all**
**Each time the script ran – whether event passed or failed filter - debug information was added, increasing event size**
**Expect to see a drop in event size of factor of 2 for these type of events**
**Added more L2 rejection to 2 tau & 1 top trigger**
**Removed obsolete jet triggers**
**Increase L1 output rate by 10%**

## Store 1808

**L1~450 Hz**

**L1 output**
**Rate in Hz**

**L2 output**
**Rate in Hz**

**L1 FEB**
**Rate in Hz**

## Store 1824

** ****L2 CAL & Muon **
**Special Runs**

- Pbar Spikes

**Store 1824 ended ~05:30 Oct 5th**
**Store 1825 began ~ 08:15 Oct 5th**

**L1~500 Hz**

## Plans for Upcoming Week

**Continue with trigger list  ****global_CMT-8.40**
**We are conservatively increasing our L1/L2/L3 output rates without sacrificing stability**
**Baseline before this past weekend at the beginning of physics run:  L1~400-450, L2~150-200, L3~40-45 Hz**
**Stores 1824-1830**
**L1/L2/L3 ~ 500-550/200-220/50-55 Hz **
**75-80% efficiency of Recorded/Delivered Lumi**
**No urgent jobs requiring Controlled Access**
**Looking forward to a full week of steady physics data taking!**