Beam-Test@CERN

I.LaktinehIPNL/IN2P3/UCBL

I.Laktineh-IPNL 2

Aims

• Test a mini DHCAL with new generation embedded electronics readout in beam conditions for the first time

• Use the high precision provided by EuDet telescope to study the inefficiency of GRPC

due to inter-pads and edge effects.

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Interpad: 500µ

HV

Signal

Graphite

Resistive platesGas

Pick-up pads

GRPC

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Test @ps-T10

Eudet Telescope

Mini DHCAL

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Test @ps-T10

Photogrammetry measurement

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EuDet Telescope photogrammetric spots

used for alignment

Moveable table

Test @ps-T10

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Spots positioning on both EuDet telescope and DHCAL Setup

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Beam position

Detector primary position

Detector next position3500 µ shift

(half of the sensor width)

.

.

.3 cm shift

For each position : 2000-3000 triggers

GRPC

GRPC

GRPC

The touched pads in the 4 GRPC for successive positions

Second threshold

First threshold

32X8 pads

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Clusters and tracks reconstruction in mini DHCAL

Clustering :touched pads were gathered into clusters if relative distanceis less than 2cm.Pads having only one threshold: weight = 1Pads having two thresholds : weight = 2

Tracking :Clusters belonging to different detectorswere gathered into tracks if compatible with straight line

A simple reconstruction algorithm was used to study the GRPC detectors

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Inefficiency Study using EuDet Telescope

• The available beam at T10 is made of 1-6 GeV pions. 6 GeV pions were used for this study

• SciPM+TLU system was used as trigger for both EuDet telescope and the DHCAL so events in both detectors were associated.

• Due to multiple scattering in the 4 GRPC’s of the mini DHCAL (even with no absorber) only the first arm (3 sensors) was used to reconstruct tracks

• Using the alignment result from the photogrammetry measurement, tracks reconstructed in the first arm were projected to the GRPC’s. The clusters associated to those tracks are recorded.

• The efficiency of tracks reconstruction in Eudet is between 50 and 60%.

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expected position%seen for found clusters GRPC clusters position

Position expected from EuTelInter-pads position

preliminary

micron

Arb

itra

ry u

nit

Edge

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preliminary

Black: expected clusters from EuTelRed : Seen in GRPC

No clear evidence of the Inter-pads effect

Interpad position

micron

Edge position

Important edge effect?

?

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Black : Tracks associated to clusters with (1or2)threshold padsRed : Tracks associated to clusters with 2-threshold pads

preliminary

micron

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Conclusion• The beam test realized using EuDet telescope was

very fruitful• Preliminary results show an edge effect but this

should be more investigated• No inter-pad effect in the GRPC (within the

available statistics). New version of GRPC with improved frame should reduce this effect.

• Apply the same study to the other three GRPC detectors.