Analysis of MDT chamber performance in terms of efficiency and noise rate

1. Motivation 2. Basic idea 3. Description of the analysis 4. Application to the measurament of the RPC induced noise 5. Conclusions Silvia Ventura Univerity of rome “Tor Vergata” Infn - Frascati

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

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.

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.

BML1 Plot di beam profile BML2 Tubes number BML1 & BML2 Multilayer 1 Layer 3

TDC & ADC spectra

Events out of time Events in time Events out of time Events with ADC<40 Events with ADC > 40

TDC spectrum BIL multilayer1 layer3 5801550 ADC > 40 ADC < 40 ADC spectrum

TDC spectrum BML multilayer1 layer1 5801550 ADC > 40 ADC < 40 ADC spectrum

So we choose to define 4 different categories of events: 1. 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 1.....

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

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

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

Evaluation of noise rate

Noise(Hz) = counts(ADC<40)/( D t x triggers) Hz BML1 BML2 BML1 & BML2 multilayer 1 Layer 1 Additional studies: Do RPC induce noise?

Data sample:

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

Runs without RPC… For all the layers the noise averaged on all the tubes Hz Run 700090 Hz BIL BML BOL BIL1,BML1,BOL1 BIL2,BML2,BOL2 BIL BML BOL

Noise from RPC (?)

Runs with RPC... Run 1764 Hz Hz Run 1559 BIL BML BOL BIL BML BOL BIL1,BML1,BOL1 BIL2,BML2,BOL2

Noise from RPC: Conclusion

Averaging the noise on all the chamber we see that there is not a significant difference of noise rate Hz BIL1, BML1, BOL1 BIL2, BML2, BOL2 Hz

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

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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