64-Straw Prototype

transcript

64-Straw Prototype Vito PalladinoCERN 07/04/2013

OutlinesThe 64-straw prototype, in building 154, is our “easy” hand-on test bench. We are using the prototype to:- Debug the DAQ - Study

- the time resolution- The r/t dependence - HV and gas mixture signal dependence - CARIOCA behavior and characterization

(charge injection)03/04/13

Experimental Setup

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TriggerScintillators (10x10x1 cm3 )

Experimental conditions:HV 1750VGas 70-30 Ar-CO2

DAQThe DAQ debugging was one of the

main task of the activities done on the prototype. The DAQ anomalous behavior was analyzed and the bug found. New data from prototype were encouraging, and a data taking campaign started. The DAQ uses a SRAMs as buffers for data and trigger timestamps, SRAMs are not overwritten (as we will do in the final version) data are acquired and than the buffer read off line.

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DAQDuring the TR we observed data in

channel suppose to be silent, the plot shows the data from 4 covers and only ch 38 is expected:

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DAQA similar plot done after the bug

fixing (1 cover), only ch 3 was expected:

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Trailing EdgeTrailing edge expected at the same time

(maximum drift distance is always the straw radius):

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Leading EdgeLeading edge for time resolution

measurement needs trigger time resolution subtraction and dependence from the wire distance:

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Time Width

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The time with has been measured using events with single edges couple:

Time Width

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The time with distribution shows two behavior, this is enhanced in the leading vs trailing plot:

Charge Injection

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In order to study the CARIOCA response to known signals we inject charge (~40 fC) from the rear-end of the straw (ch 7 -> CARIOCA analog output).

PulseGenerator

(Dual-timer)

Straw 7Back-end

SRB (NIM trigger input)

Attenuator

RC circuit

CARIOCA CH 7

Charge Injection

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The trigger-data delay has been measured and we verified, that the peak we were studying was actually the signal peak (threshold 0.95 V):

Charge Injection

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I took advantage of the signal reproducibility to have the first sampling of the signal “observed” by CARIOCA.

Charge Injection

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TH (?)

Charge Injection

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Charge Injection

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Conclusions And Schedule We are finalizing the DAQ debugging, main problems have

been faced and solved. Still we have to commission the on-line readout or SRAMs

First results with prototype are conflicting. Charge injection shows that the DAQ and electronics can reach optimal results, but cosmic data shows time resolution that are not clear.

We have to study the behavior of the electronics coupled with the detector.

In particular some tests are planned for the upcoming weeks/months:◦ Using the external tracker (micromegas) to:

- Measure the r/t curve- Measure the (leading) time resolution as function of wire distance

◦ Measure the data delay respect to the trigger (done -> 2.86 ms) ◦ Comparison with previous COVER version◦ Trigger time resolution (on going in 154)

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Run 368300 out of ~600 bursts match triggers

quality cut (same number of triggers in the SRBs)

132 bursts out of 300 good for data analysis (contamination lower than 5 per mill )

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Results (wire distance ch 10)Wire distance measurement has been performed using the drift velocity curve measured during the test beam

Time (ns)03/04/13

Technical Run Experimental Setup

= active regions

View V

View U

Jura Saleve

- 2 views- 4 covers per view- 2 SRB read via VME

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Beam ProfileWe were able to see the beam profile as we

expected, warning: the straws are not plotted in order.

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Burst StructureAlso the burst time structure has been

measured.

SOB EOB03/04/13

Bad Words and Data Contamination Data suffers of contamination due to lost of part of

data structure, some times this was recognizable and data can be used. But in many cases this was not possible.

Spill Time Structure

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Bad Words and Data Contamination Data suffers of contamination due to lost of part of

data structure, some times this was recognizable and data can be used. But in many cases this was not possible.

Beam Profile Structure

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Data SelectionReadout problems -> data selection

◦ Mismatch between the SRBs number of triggers

◦ “Bad Words”Analysis performed on a run taken in

low intensity conditions (0.1 x1011 protons on T10)

Quality cuts applied to data contamination (<5 per mill)

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Results (“assumed” drift velocity curve)

Drift Time (ns)

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64-Straw Prototype

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