# Presentation: 857981

## Barrel PreShower cal status

- Jaroslav Bielcik Yale/BNL

-  Where we have been
-  Where we are
-  Where we go

## Motivation

-  integrated dep .energy in first 2 emc layers
-  to bemc tower we have bprs information
- 2x60 modules totaly
- 20x2 towers in module

**Electron Id** should be improved

- Module side view

- Details http://www.star.bnl.gov/protected/heavy/bielcik/prs/preshower_cal.htm

## Where we have beenTo do July 2004

-  Check prs mapping
-  Understand prs/bemc/track  correlations
-  Simulate deposit MIP particles ~ eta
-  Complete calibration
-  Determine improvement of electron Id

## Problems to find MIP

-   **Idea:**  project TPC tracks on BPRS and for those plot ADC spectra
-   Most tracks are hadrons => ADC spectrum corresponds to MIP
-   We expect to see difference: **all ADC**  and MIP

-  _However_: no significant difference has been observed?!! **PANIC**
** ****Trying a lot => no MIPs**

**MIP ???**

## MIPs in simulations

-  Looking in AuAu62 Hijing simulations to get a right feeling

- Clear visible MIPS
- position~energy
- Channel:  7-8
- Deposit energy:   35-50 MeV

**Problem should be outside the MIP anal**

**maybe map, maybe map ...**
**How to check?**

## Correlating BPRS signal around projected track position

-  Tpc track  projected on BPRS tower (m,s,e)
-  check towers ADC>0 around this place 4x4
-   marking them -4-4; 0 is proper position
-  Signal in tower 0 is expected to dominate

## Spectra for all towers

- Sum over all towers shows that expected tower dominates
- WELL MAP seems to be OK.     Let check each towers separately

- Tower “0” is not always dominating ???

## Each tower separately

**Few towers make good job for rest**  (what about rest?)

##    Correlating BPRS and BTOW

**Subhasis Method**

-    Correlating BPRS and BTOW
-     with maximum signal in event

- This is not a face of Holly Mary on toust but **weak correlation**

- How to interpret this? GOOD/BAD?

## Contributing towers to correlation

- here we see something like grass =>    **here rather like trees**

- ZOOM

**Contributing towers are groups of 4 towers => rest do not contribute**

- Here we come to the core of the problem: _**BPRS map is not OK **_
**                                                                    ****(the most probably)**

**GOOD TOWERS**: **Id=9(10,11,12)+20*i** .

## Energy correlation

## MIPs with bad and good towers

**THIS IS MIP!!!**

- GOOD TOWERS shows MIPs => that is very good news

## To do

- Subhasis talk :  shows that this was problem with MAP
-                           possible solution
- We can finnaly calibrate it **NOW it is just peanuts!**
**Study lepton ID improvement**

## Adc spectra

## BEMC geometry

- front view 60 emc modules

- module

- module

- module side view

- module top view

## ETA              MIP ADC         MIP ENERGY (GeV)  
e=  1              7.0305              0.0355 (+/-  0.0240)
e=  2              7.2614              0.0332 (+/-  0.0213)
e=  3              6.8939              0.0349 (+/-  0.0235)
e=  4              7.5919              0.0369 (+/-  0.0262)
e=  5              7.4255              0.0338 (+/-  0.0252)
e=  6              7.6160              0.0348 (+/-  0.0265)
e=  7              7.9097              0.0350 (+/-  0.0278)
e=  8              7.4636              0.0351 (+/-  0.0253)
e=  9              7.6321              0.0412 (+/-  0.0224)
e= 10             7.3018              0.0413 (+/-  0.0220)
e= 11             8.0859              0.0435 (+/-  0.0216)
e= 12             7.0524              0.0387 (+/-  0.0242)
e= 13             7.8205              0.0463 (+/-  0.0271)
e= 14             6.8425              0.0426 (+/-  0.0235)
e= 15             7.8134              0.0433 (+/-  0.0245)
e= 16             7.1765              0.0415 (+/-  0.0206)
e= 17             7.3744              0.0446 (+/-  0.0247)
e= 18             7.7141              0.0494 (+/-  0.0293)
e= 19             7.1439              0.0424 (+/-  0.0297)
e= 20             7.9555              0.0350 (+/-  0.0238)

- e=  1              7.0305              0.0355 (+/-  0.0240)
- e=  2              7.2614              0.0332 (+/-  0.0213)
- e=  3              6.8939              0.0349 (+/-  0.0235)
- e=  4              7.5919              0.0369 (+/-  0.0262)
- e=  5              7.4255              0.0338 (+/-  0.0252)
- e=  6              7.6160              0.0348 (+/-  0.0265)
- e=  7              7.9097              0.0350 (+/-  0.0278)
- e=  8              7.4636              0.0351 (+/-  0.0253)
- e=  9              7.6321              0.0412 (+/-  0.0224)
- e= 10             7.3018              0.0413 (+/-  0.0220)
- e= 11             8.0859              0.0435 (+/-  0.0216)
- e= 12             7.0524              0.0387 (+/-  0.0242)
- e= 13             7.8205              0.0463 (+/-  0.0271)
- e= 14             6.8425              0.0426 (+/-  0.0235)
- e= 15             7.8134              0.0433 (+/-  0.0245)
- e= 16             7.1765              0.0415 (+/-  0.0206)
- e= 17             7.3744              0.0446 (+/-  0.0247)
- e= 18             7.7141              0.0494 (+/-  0.0293)
- e= 19             7.1439              0.0424 (+/-  0.0297)
- e= 20             7.9555              0.0350 (+/-  0.0238)