# Presentation: 934237

## Tower 2 problem

- For about 30  BLS boards  tower 0 is read out instead of tower 2
-  the information from tower 0 appears twice (once correctly)
-  the information from tower 2 is lost
-  problem occurred for most boards during January shutdown, but some broke also at a later date
- Robert Zitoun: problem discovered from pulser run analysis
- Nirmalya et al.: fixing hardware (June/July)
- 	July 8 _[http://www-d0.fnal.gov/~parua/Cat_070803.ppt](http://www-d0.fnal.gov/~parua/Cat_070803.ppt)_
- Jan Stark: providing correction function:
-     August 5:_[http://www-clued0.](http://www-clued0.fnal.gov/~stark/CATF5aug.ppt)__[fnal](http://www-clued0.fnal.gov/~stark/CATF5aug.ppt)__[.](http://www-clued0.fnal.gov/~stark/CATF5aug.ppt)__[gov](http://www-clued0.fnal.gov/~stark/CATF5aug.ppt)__[/~stark/CATF5aug.](http://www-clued0.fnal.gov/~stark/CATF5aug.ppt)__[ppt](http://www-clued0.fnal.gov/~stark/CATF5aug.ppt)_
-  correction procedure in cal_corr_dst package
-  can be applied on tmb to correct cal_data_block
-  presented study done by Jan Stark

- convenors  meeting, August 28th, 2003

- Ursula Bassler

## Signature of tower 2 problem

- BLS board (3/2/2):
- correlation of raw ADC counts in towers 0 and 2  (depth 0) and  towers 1 and 3

**Plots for depths 1 to 11 show the same features**.

- Run 172482

- Run 177826

- tower 0

- tower 2

- tower 0

- tower 2

- tower 1

- tower 3

- tower 1

- tower 3

- convenors  meeting, August 28th, 2003

- Ursula Bassler

## Tower 3 can be also be affected

**BLS board 2/11/3 in run 177826  and run 172482**

- tower 0

- tower 2

- tower 0

- tower 2

- Depth 0

- Depth 6

- tower 1

- tower 3

- Depth 0

- tower 1

- tower 3

- Depth 3

** ****tower 3 also has the “tower 2 problem”.**
** ****for tower 2 only depths 0 to 5 are affected, for tower 3 only depths 0 to 2.**

- convenors  meeting, August 28th, 2003

- Ursula Bassler

## Correction from  L1 information? 

- L1 readout is not affected by the tower 2 problem.
-  use L1 information to correct the problem, but less precise!

- GeV

- (L1) – (precision readout)

- ieta/iphi = 2/42

- estimation of L1 precision:
-  run prior to tower 2 problem
-  compare the L1 energy in corresponding trigger tower with energy measured by the precision readout
-  E(L1) - E(RO):
-   = – 0.07 GeV   = 1.22 GeV
-  some tails!

- convenors  meeting, August 28th, 2003

- Ursula Bassler

##  Tails in L1/RO correlation

- Trig. tower: 44.5 GeV,  prec. readout: 52.8 GeV

- Trig. tower: 44.0 GeV,  prec. readout: 50.0 GeV

- ieta

- iphi

- ieta

- iphi

- GeV

- (L1) – (precision readout)

- ieta/iphi = 2/42

-  clean events
-  probably RO is right and L1 is wrong
-  L1 precision within 20 %

- convenors  meeting, August 28th, 2003

- Ursula Bassler

## Algorithm for the correction

-  **each L1 trigger tower comprises four RO-towers **
** ****subtract  energy of 3 RO-towers from L1-tower energy**
** ****L1 only provides the sum of energy in EM layers and in FH layers **
****** ****distribute equally among the different EM (FH) layers, set CH to zero**

- true energy

- predicted energy

- true energy
- (excluding CH)

- predicted energy

-  good correlation, but slope  1, even without CH contribution
-  latest L1calibration factors not used yet.

**simulate procedure: total energy in tower 2 vs energy predicted by correction**

- convenors  meeting, August 28th, 2003

- Ursula Bassler

## Case if towers 2 and 3 are affected

- true energy
- (including CH)

- predicted energy

- true energy
- (including CH)

- predicted energy

-  **tower 2 and  3 of a BLS board are part of the same trigger tower **
** ****only the energy sum of the two tower is recovered with good precision**
** ****split energy more or less arbitrarily between the two towers. **
** ****should be good enough for missing E****T**** and typical cone jet.**

- Individual towers:

- Sum of the two towers:

- convenors  meeting, August 28th, 2003

- Ursula Bassler

## Limited L1 eta coverage

-    crate adc bls   ieta iphi
- ----------------------------
-      3    2   2      2   42
-      3    6   2      6   32
-      8    2   4      6   10
-      8    5   6     10    2
-      8    7   2     10   62
-      8    8   2      2   58
-      8   10   0      6   54
-      9    0   6     -2   51
-      9    6   0     -2    1
-      9    8   0    -10    5
-      0    3   0    -14   37
-      0    8   4    -30   43
-      0    9   0    -14   45
-      1    6   4    -22   25
-      2   11   3     -4   47
-      6   10   4     14   50
-     10    0   5    -24    1
-     10    4   6    -18    7
-     11    2   0    -22   51
-     11    3   1    -16   53
-     11    5   5    -32   55
-     11    7   1    -32   57
-     11   10   7    -20   63
-     11    4   4    -14   55
-      1    9   4    -22   29
-      2    9   2     -6   41
-      1   11   3    -28   31 (affects only runs with extended L1 eta coverage)
-     10   11   5    -32   15 (affects only runs with extended L1 eta coverage)

-   BLS boards known to be  affected by the tower 2 problem during some period of time
-  trigger list v10.x:    -24  ieta  24
-  TL v11.x and later: -32  ieta  32
-  3 boards outside L1 coverage in TL v10.x
-  no information available!
-  take these towers out in all runs during this period

- convenors  meeting, August 28th, 2003

- Ursula Bassler

## Impact on missing ET

-  simulate the tower 2 problem on 15k events from a run that precedes the problem
-  compare missing ET distribution with and without tower 2  problem
-  = – 0.1 GeV   = 1.5 GeV
-  tails up to 40 GeV

- convenors  meeting, August 28th, 2003

- Ursula Bassler

## Impact on missing ET

-  same distributions after corrections
-  = – 0.01 GeV   = 0.9 GeV
-  some outliers

**noise problem**

**CH not treated by corrrection**

- convenors  meeting, August 28th, 2003

- Ursula Bassler

## Impact on jets: an example event

-    pT       eta        phi
- ----------------------------
- 92.9795   0.947578   6.01831
- 91.5699  -0.776211   2.78362
- 11.4774   0.221958   4.92006
-  9.1915  -1.04239    4.34488
-  8.9408   0.643591   1.55351
-     -         -          -

-     pT       eta        phi
- -----------------------------
- 127.353    0.977964   6.02065
-  91.5699  -0.776211   2.78362
-  11.4774   0.221958   4.92006
-   9.0071  -1.03703    4.34439
-   8.9408   0.643591   1.55351
-      -         -          -

- Comparison on all jets in an example event
- (not a typical one, though)

- Without tower two problem

- With tower two problem

-     pT       eta        phi
- -----------------------------
-  92.0136    0.94604   6.01678
-  91.9203  -0.776675   2.78526
-  11.4774   0.221958   4.92006
-   9.0071  -1.03703    4.34439
-   8.9408   0.643591   1.55351
-   8.2105  -1.66933    0.29836

- After correction
- (as it is implemented now)

**The correction fixes the gross mistakes, **
**but cannot get all the little details right!**

- convenors  meeting, August 28th, 2003

- Ursula Bassler

## Summary

-  tower 2 problem appeared since January on ~30 BLS boards
-  hardware has been fixed in June/July
-  effect on data and correction studied in detail
-  correction procedures provided in cal_dst_correct package (since August 3rd)
-  some fine tuning may still be done

- convenors  meeting, August 28th, 2003

- Ursula Bassler