1. Univerity of rome “Tor Vergata”
Analysis of MDT chamber performance in terms of efficiency and noise rate
Motivation
Basic idea
Description of the analysis
Application to the measurament
of the RPC induced noise
5. Conclusions
Univerity of rome “Tor Vergata”
Infn - Frascati
Silvia Ventura

2. Motivation The main motivation is to study
and implement a fast monitoring
procedure for off-line and possibly
on-line data analysis, in order to
check the efficiency and the noise rate
of the MDT channels

3. Basic idea The basic idea is to use the
hit counting rate (beam profile)
together with the information avalaible
from the MDT channels, that are
the TDC and ADC values.

4. BML1 & BML2 Multilayer 1 Layer 3
Beam Profile
From the beam profile one can obtain information about the noise and the efficiency. In particular we study the beam profile of all the layers.
Hit counts
BML1
BML2
Plot di beam profile
Tubes number
BML1 & BML2 Multilayer 1 Layer 3

5. TDC & ADC spectra Hit counts Hit counts Events Events in time Events
out of time
Events
out of time
Hit counts
Events
with
ADC<40
Events
with
ADC > 40
Hit counts

6. TDC spectrum ADC spectrum ADC > 40 ADC < 40
BIL multilayer1 layer3
ADC spectrum
580<TDC <1550
TDC<580 , TDC>1550

7. TDC spectrum ADC spectrum ADC > 40 ADC < 40
BML multilayer1 layer1
ADC spectrum
580<TDC <1550
TDC<580 , TDC>1550

8. So we choose to define 4 different
categories of events:
ADC > 40 out of time
2. ADC < 40 out of time
3. ADC > 40 in time
4. ADC < 40 in time
…and look at the corresponding beam profile
for the BML multilayer 1 layer

9. Beam profile for the 4 categories:
ADC>40
Out of time
ADC<40
Out of time
ADC>40
In time
ADC<40
In time
BML1 & BML2 multilayer 1 Layer 1

10. For all the categories we integrate on all the tubes for each layer  Nlayer
ADC>40 Out of time
ADC<40 Out of time
BIL
BML
BOL
ADC>40 In time
ADC>40 In time

11. We can get information about: Noise rate using 2 and 4
The 4 categories are:
1. ADC > 40 out of time
2. ADC < 40 out of time
3. ADC > 40 in time
ADC < 40 in time
We can get information about:
Noise rate using 2 and 4
Efficiency using the clean
beam profile of event 3

12. Evaluation of noise rate
Noise(Hz) = counts(ADC<40)/(Dt x triggers) Hz
BML1
BML2
BML1 & BML2 multilayer 1 Layer 1
Additional studies: Do RPC induce noise?

13. Data sample: Data from test beam 2003 H8: Run number Active detectors
700090
MDT
700108
700334
1091
MDT + RPC
1165
MDT (only BIL2,BML2,BOL2) + RPC
1559
1764

14. Noise from RPC (?) Run 700334 Run 700090 Runs without RPC…Hz
For all the layers
the noise averaged
on all the tubes
BIL
BML
BOL
Run Hz
BIL1,BML1,BOL1
BIL2,BML2,BOL2
BIL
BML
BOL

15. Noise from RPC (?) Run 1764 Run 1559 Runs with RPC... Hz Hz BIL BML
BOL
Run 1559 Hz
BIL1,BML1,BOL1
BIL2,BML2,BOL2
BIL
BML
BOL

16. Noise from RPC: Conclusion
Averaging the noise on all the chamber we see that there is not a significant difference of noise rate Hz
Run
Run
Run
Run 1559
Run 1764
BIL1,
BML1,
BOL1
Run 1091
Run 1165
BIL2,
BML2,
BOL2 Hz

17. Beam profile for all the layer
Efficiency
Using the beam profile of events in time with ADC > 40 we can evaluate
the efficiency for all the tubes of a layer
BML mutilayer1
layer1
layer2
layer3
Tubes number
Beam profile for all the layer
Tubes number
Shifted tubes number

18. Conclusions:  An analysis has been made of the hit counting rate
and of the TDC and ADC information to determine the
efficiency and noise rate of the MDT channels.
 The ADC cut is powerful in selecting signal and noise hits.
The application of this analysis to study the RPC induced
noise has shown that it was negligible at H8
The comparison of the beam profiles observed in the
various active detector layers makes the analysis
indipendent of the actual beam profile.
A code to perform sistematically the analysis and
determine efficiency and noise rate for all individual
channels is under development