icroMegas - indico.cern.ch · High gain gaseous detector 2. ... Date offset: (msec from absolute start of time (1904) to the ﬁrst msec of current date Startime: timestamp of run

µicroMegasMicroMEsh GAseous Structure

Muons Atlas Micro Megas Activity

Faruk DiBLEN

Cern-TR Meeting

12.08.20091

What is Micromegas?

Invented in 1995* by Giomataris and Charpak (1992, Nobel Prize, Multiwire proportional chamber)

Two-stage parallel plate avalanche chamber

Narrow amplification gap defined by the anode plane and a cathode plane

High gain gaseous detector

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http://en.wikipedia.org/wiki/Multiwire_proportional_chamber




Micromegas detectors for the CAST experiment

The CAST experiment is designed to study the possible emission of axions from the Sun's core.

Temporal projection chambers (TPCs) for the T2K experiment

Three TPCs for the Japanese T2K neutrino oscillation experiment

TPC-based trajectograph for future electron colliders

Cylindrical detector for the CLAS12 experiment

Neutron flux monitor for the NTOF experiment

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TestBeamSparks will be a problem in SLHC conditions with today’s Micromegas detectors

Standard bulk detectors will not handle the neutron and hadron flux at forward ATLAS conditions sparks, dead time,damage the detector if persistent

Possible solutions

– Resistive films

– Segmented mesh

– Double amplification

The Saclay group decided to realise an R&D on resistive films on

small prototype (10 cm2) detectors

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Resistive Technology

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Spark Measurement

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TestBeam Data

Data Structure

Binary data

8 detector data in same file

Words of 4 bytes (32 bit)

Run Header

Events

Run Footer

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Run Header

1st: Run header start-flag

Run number

Date in the format Date=Year*10000 + Month*100 + Day */

Date offset: (msec from absolute start of time (1904) to the first msec of current date

Startime: timestamp of run start. Because of precision problems it is defined as: absolute(timestamp of run start) – Date offset.

Run type (0,1,2,3,… data, calibration , pedestal, background …)

Magnetic field

Magnet Gas

Detector’s number

HV1 (drift)

HV2 (mesh)

Micromegas gas (% of isobutane)

Run header end-flag

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Event Structure1st: Event start-flag

Event ID (DAQ)

Event’s timestamp ( from date offset )

A trigger counter

Number of ADC data words.

Number of channels

Strip data format: ndata words of 32 bit.

Bit 0-11 is the strip charge

Bit 12-22 is the strip ID (DECODING ???)Bit 30 is valid flag Bit 31 is overflow flag Bits 23-29 are reserved

i. Word 1

ii.Word 2

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Event end-flag

Next Event17

Run Footer

1st: Run footer start-flag Total number of events

End time – from date offsetRun footer end flag

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Software

Software(c/c++)

Map1

Map2

Map3

Map4

Map5

Map7

Map6

Map8

Detector order

Analysis data file

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ProblemsExample1:

Strip: 93 Data: 62 vld : 1 ovf : 0



Strip: 0 Data: 0 vld : -1880988508 ovf : 126 NON-VALID strip found...

Strip: 0 Data: 0 vld : -1880988508 ovf : 126 NON-VALID strip found…

Example 2:




Strip 68?



Strip: 71 Data: 19 vld : 1 ovf : 0 21

Example 3:




Strip: 50440304 Data: -1073751624 vld : -1809429542 ovf : 50440384 NON-VALID strip found...

Example 4:







Run Header (run info)

#############RUN INFO#################

Run number : 5117

Run date : 20090609

Run start time : 75063

Run type : 0

Magnetic Field : 94000

Magnet Gas : 0

HV1 : 500385

HV2 : 500000

Gas : 50

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Event Header

###############EVENT INFO######################

Event ID : 1

Event time : 75245334

Run type : 0

Nwords : 96

Counter 1 : 11

Counter 2 : 387

...

Counter 8 : 0

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Event Header##############EVENT INFO######################

Event ID : 1

Event time : 75245334

Run type : 0

Nwords for detector 1 : 96



…

Nwords for detector 8: 96

Counter 1 : 11

Counter 2 : 387

...

Counter 8 : 0

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Reading Data

Read Run Footer

Read events

Read strip id, charge, validity, overflow

For each event check end of event

If event ends goto next event

Check end of file for every words

If run footer is found finish reading

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StripsFind Strips which are not exist

Number of strips for detector 1 BEFORE correction is 95

In detector 1 Strip 68 is missing...

Number of missing strips is 1

Number of strips for detector 1 AFTER correction is 96

************************************************************




...

*************************************************************







Set strip charge value to -1 if strip is missing

Set Nwords28

Correction Example 1:

Corrected Det : 1 Strip : 66 cntr : 66 data : 22


Corrected Det : 1 Strip : 68 cntr : 68 data : -1



Example 2:



Corrected Det : 4 Strip : 30 cntr : 30 data : -1



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Decoding

Detectors(0-7):

0 1 2 3 4 5 6 7

Read map files for 8 detectors

Status: 1

Strips:

3 1 7 5 11 9 15 13 19 17 23 21 27 25 31 29

30 32 26 28 22 24 18 20 14 16 10 12 6 8 2 4

35 33 39 37 43 41 47 45 51 49 55 53 59 57 63 61

62 64 58 60 54 56 50 52 46 48 42 44 38 40 34 36

67 65 71 69 75 73 79 77 83 81 87 85 91 89 95 93

94 96 90 92 86 88 82 84 78 80 74 76 70 72 66 68

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Detector order file

Map file

Decoded stripsBefore decoding








After decoding

Decoded Det : 0 Strip : 2 cntr : 0 data : 48






Map for first 4 strip

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Decoded strips 1st strip 2nd strip 3th strip 4th stripStrip before decoding 3 1 7 5

References

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-Status Report of the Saclay Telescope in June MAMMA Testbeam Micromegas Weekly Meeting

-Upgrade of the ATLAS muon chambers for the sLHC CEA/IRFU/SEDI M. Boyer, J. Derré, E. Ferrer-Ribas, A. Giganon, I. Giomataris, S. Herlant, F. Jeanneau ,WG1 Meeting - 21/01/2009

-Micromegas in a bulk Nuclear Instruments and Methods in Physics Research A 560 (2006) 405–408

-Micromegas, a multipurpose gaseous detector Nuclear Instruments and Methods in Physics Research A 478 (2002) 26 –

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THANKS!

Documents

icroMegas - indico.cern.ch · High gain gaseous detector 2. ... Date offset: (msec from absolute start of time (1904) to the ﬁrst msec of current date Startime: timestamp of run