# Presentation: 278965

## SMT pedestal management

- Weekly NIKHEF – NIJMEGEN – D0 meeting
- 	June 6, 2001
- Freya Blekman
- Summary:
- Outline of current SMT status
- What is the next step?
- SDAQ vs. PDAQ
- Yet again: Databases
- The smt_ped_tools
- Some results

## SMT status (current)

- 100% of the SMT is now cabled
- 95 % of the barrels has been read out
- For the F-disks and H-disks, this is a bit lower (around 90%)
- Still some HV problems, nothing major.
- Still only running in full-readout mode.

## What is the next step?

- We can now only run whilst reading out all (=800,000) channels of the SMT.
- This load is not possible for the DAQ (nor will it ever be)
- SMT will eventually be running in sparse mode
- ‘sparse’ = with pedestal subtraction *on *the svx readout chip (~= ADC) and zero-surpression.

## What to do: get those Pedestals!

- Every channel has its own ADC.
- The pedestal values have only been measured in lab, and even there not very well.
- When downloading the chip, the pedestals can be set.
- Pedestal values are retrieved (per channel) in the calibration database and in the online (=‘hardware’) database

## Pedestal measurement

- At D0, there are two ways to measure the pedestal values of the silicon
- 1. Take data and look at the average data per channel
- 	(= Primary Data Acquisition)
- 2. When not running, put charge on every channel and do a raw pedestal measurement.
- 	(=Secondary Data Acquisition)

## SDAQ vs. PDAQ (1)

- PDAQ + : Use the data you already have to compensate. ‘Standard’ way to do it.
- PDAQ - : You need data ! (and lots of it)
- PDAQ - : Cannot readout full SMT unless sparse mode: will only be reading out channel with hit and two neighbors.

## PDAQ vs. SDAQ (2)

- SDAQ + : It’s relatively quick.(few hours)
- SDAQ - : It’s not clear that charge deposition on Si strips has the same result as real life.
- SDAQ - : Remove SMT from global run.
- SDAQ - : Program still very unreliable
- (for instance, it ignores the 9th chip on 9-chip ladders. 50% of the SMT barrel detectors are 9-chip ladders.)

## Several SDAQ runs (unbiased ladders)
Database problems (solved now)
smt_ped_tools (in cvs)
ROOT-based gui
Create_ntuple program 
SMT_pedestals.root
Some small macros

- Database problems (solved now)
- smt_ped_tools (in cvs)
- ROOT-based gui
- Create_ntuple program
- SMT_pedestals.root
- Some small macros

- Last few weeks:

## create_ntuple.x

- CPP code
- Uses 2 packages:
- D0omORACLE
- Connects to ORACLE calibration DB
- HepTuple
- Creates root files
- Creates root ntuple

## create_ntuple.x (2)

- Why not directly in root?
- Too much trouble with TSQL classes in root.
- TSQL works (after a lot of work) on linux, _when_ you have administrator privileges.
- One of the CDF ORACLE gurus recently (last month) got it working at fnal.
- I decided that it wasn’t worth wile trying, you don’t want to connect to the database every time anyway.

## Smt_ped_gui.C

- Uses ROOT
- ROOT has gui classes
- Is essentially a big root Macro
- Plots averages as a function of run number.
- Options for HDI type selection

## Smt_ped_gui/rootMacros/

- Ready:
- Channel maps (semi-interactive)
- Near future:
- Pedestals  as a function of integrated luminosity
- is dependent of availability of
- My time
- Luminosity data (Mike Begel)

## Results (1)

**Direct output of**
**smt_ped_tools/**
**smt_ped_gui.C**

## Results (2)

- Run 121545
- Ladder type
- Barrel 4
- Layer 2
- Ladder3
- Double-sided,
- 6 svx chips
- one of the detectors closest to (0,0,0)

## Results (3)

- Run 121545
- Ladder type
- Barrel 4
- Layer 3
- Ladder3
- Double-sided,
- 9 svx chips
- SDAQ 9th chip problem visible