# Presentation: 401159

## The RunII D0 CalorimeterElectronics Upgrade & Its PerformanceNirmalya ParuaState University of New York Stony BrookCalor 200210th International Conference on Calorimetry in High Energy Physics CalTech, Pasadena March 25-29, 2002

## Tevatron Run I (1992-96)

- Very successful Run I
- p-pbar collisions at √s = 1.8 TeV
- L *dt* ~ 120 pb-1 delivered to DØ and CDF
- Peak luminosity ~ 1.6 x 1031 cm-2 s-1
- Many exciting studies, including
- Top discovery
- Mt = 172.1  5.2 (stat.)  4.9 (syst.) GeV/c2
- tt = 5.9  1.7 pb (DØ combined)
- W mass measurement
- MW = 80.482 ± 0.084 GeV (DØ combined)
- Limits on anomalous gauge couplings
- Limits on SUSY, LQ, compositeness, other exotica
- Tests of QCD + Electroweak
- b-quark physics
- 116 published papers
- >60 PhD theses

## Fermilab Accelerator Upgrade

- Two new machines at FNAL for Run II:
- Main Injector
-           150 GeV conventional proton accelerator
- Supports luminosity upgrade for the collider
- Recycler
- 8 GeV permanent magnet (monoenergetic)
-      storage ring
- permits antiproton recycling from the collider
- Tevatron Status and Schedule
- 1.8 Tev  1.96 TeV
- Goal: L *dt* = 2 fb-1     in Run 2a
-                          15 fb-1+ in Run 2b
- Very first p-pbar collisions seen (August 2000)

## Bunch Structure

- Detector readout and trigger system upgrade must take into account smaller bunch crossing time

## Overview of D0 Upgrade

**Upgrade Calorimeter Readout**
**Add scintillator detector in muon system for faster trigger**
**Silicon and Fiber tracker with 2 Tesla solenoid magnetic field for central tracking and momentum measurement.**
**Add Pre-shower detectors.**
**Pipelined 3 Level trigger**

## Calorimeter Overview

**Liquid argon sampling**
**Stable, uniform response, rad. hard, fine spatial seg****.**
**LAr purity important**
**Uranium absorber (Cu or Steel for coarse hadronic)**
**Compensating e/******** ******** 1, dense ******** compact****  **
**Uniform, hermetic with full coverage**** **
******< 4.2 (******** ******** 2****o****), ********int ********total) **
**Energy Resolution**
**e: ********E**** / ****E**** ****= 15%**** /********E********+ 0.3%  ********:  ********E**** / ****E**** ****= 45%**** /********E +  4%   **

- Drift time 430 ns

## Intercryostat Detector (ICD)

**Design **
**Scintillator based with phototube readout similar to Run I  design.  Re-use existing PMT’s (Hamamatsu R647). **
**16 *****supertile***** modules per cryostat with a total of 384 scintillator tiles**
**WLS fiber readout of scintillator tiles**
**Clear fiber light piping to region of low field ~40-50% signal loss over 5-6m fiber. **
**Readout/calibration scheme for electronics same as for L. Ar. Calorimeter but with adapted electronics and pulser shapes**
**LED pulsers used for PMT calibration**
**Relative yields measured > 20 p.e./m.i.p.**

- Objectives
**Improve coverage for the region  **
**    ****1.1 < |********| < 1.4**
**Improves jet E****T**** and E****T   **
**Maintain the performance in the presence of a magnetic field**

**ICD**

**FPS**

## Upgrade of Calorimeter Readout 

- Objectives and Performance Criteria
- reduced minimum bunch spacing from 3.5 s to 396 ns (132 ns at RunII B).
- Storage of analog signal for 4 s for L1 trigger formation
- Generate trigger signals for calorimeter L1 trigger
- Maintain present level of noise performance and pile-up performance
- Methods
- Replace preamplifiers
- Replace shapers
- Add analog storage
- Replace calibration system
- Replace timing and control system
- Keep Run I ADCs, crates and most cabling to minimize cost and time

## Upgrade of Calorimeter Readout

**Bank 1**

**Preamp/**
**Driver**

**Trig. sum**

**Filter/**
**Shaper**

**x1**

**x8**

**SCA (48 deep)**

**SCA (48 deep)**

**SCA (48 deep)**

**SCA (48 deep)**

**Bank 0**

**Calorimeter**

**Calibration**

**55k readout channels**

- A n. Bu
- f
- f

- A
- D
- C

- 48

- 1

- peak

- base

- Cable replaced for impedence matching

## Preamplifier

**FET**

- New calorimeter preamp
- Hybrid on ceramic
- 48 preamps on a motherboard
- New low-noise switching power supplies in steel box

- New output Driver for terminated signal

**1152 boards**

** **

- 55296 hybrids

## Base Line Subtracter (BLS)

**ADC’s have 12 bit dynamic range. To achieve 15 bit dynamic range SCAs have low and high gain path for each readout channel (X8/X1)**
**SCAs are not designed for simultaneous read/write operations. Two banks of SCAs, upper and lower (can’t see in the picture), for alternate read/write operation****.**
**Readout time ~6 ****μs (length of SCA buffers 132 X 46 >6 μs). **
**Trigger tower formation 0.2 X 0.2 for Level 1.**

##  T&C cards

- Receives trigger, accelerator, clock information
- Samples BLS shapers at the signal peak and base.
- Keeps track of the memory location of crossings.
- Generates busy signal when system is not ready.
- Coordinates pulser calibration.

- 12 T&C boards and 1 controller board is used

## Impedance Measurement

## Debugging and Noise

- Presently we have very few bad readout  channels  (<0.1%)

- Shows the level of Noise

- We are using 2.5* as the zero suppression limit while taking data.
- Fine Tuning this limit is underway.

## Finer Debugging

- 

- 

- 

- 

-     

- x8

- x1

- L1 SCA

- up

- L2 SCA

- ADC

- down

- Mean value

- Most problems are traced to slower SCA chips.
- More than 250 SCA chips (~1%) have been replaced

- D0-France 28/11/2001

## Coherent Noise Studies.

- Normalized Covariance
-  = (1/n)  { ( Xi – Xave ) ( Yi – Yave ) / ( x y ) }

- Look at the coherence with other channels.
- Check the noise introduced by the other detectors.

## L1 Calorimeter Trigger 

- Miscabling

- All towers at || <0.8 are instrumented,  complete coverage coming soon

## Summary of Installation  & Commissioning

**Only missing piece is Trigger readout for |********|>0.8**

## Timing Studies

** ****-20 ns   99.69%**
** ****-10 ns   99.92%**
**   ****10 ns   99.93%**
**   ****20 ns   99.71%**
**   ****50 ns   98.23%**

- Sampling time vs amount sampled

- Nominal sampling time varies from ±10ns

- Pedestal Values were           different for Early,  Nominal or Late   sampling.
- Corrected after putting additional CAPS on BLS boards.

- 132 ns early

## Online Data Quality Check

- Shifter’s are continuously           monitoring quality of data.
- When hot cells are found corresponding readout channels are suppressed.

## Calibration Using Pulser

- Pulser signal injected here (measured in DAC counts)

- DAC/1000

- Non linearity <0.5% for DAC>1000
- For Lower DAC values non linearity is significant but can be parametrized (same for all channels).

- saturation

**More in Ursula Bassler’s talk**

## Effect of Non Linearity 

- Non Linearity seems to have significant effect but can be corrected off line.

## W/Z candidate

- With Non-linearity correction put in

- W(e+jets selection

- 118 events
- Signal:~75

- 335 events
- Signal:~200

- Mean 83.7

- Mean 89.4

## Multi jet events

**  ****2-jets event**
-  ETjet1~230GeV
-  ETjet2~190GeV

**  ****3-jets event**
-  ETjet1~310GeV
-  ETjet2~240GeV
-  ETjet3~110GeV
-  ET~8GeV

- A. Kupco

- reunion du vendredi 14/12/2001

## QCD Physics

## Jet Energy Scale

- Et=27 GeV

- Et=24 GeV

- Photon-jet Events

## Outlook

**D0 has undergone major detector upgrade.**
**Liquid Argon Calorimeter remained untouched.**
**But major upgrade for readout has been done.**
**We are making rapid progress in understanding new calibration, energy scale etc.**
**Benchmark Physics processes are being scrutinized to better understand the detector.**
**New results will become available soon.**