Villa Olmo, Como 15-19 October 2001 F.Giordano 1

SiTRD SiTRD RR&&DDThe Silicon-TRD: Beam Test

ResultsM.Brigidaa, C.Favuzzia, P.Fuscoa, F.Garganoa,

N.Gigliettoa, F.Giordanoa, F.Loparcoa M.N.Mazziottaa, M.Prestb, S. Raino’ a, P.Spinellia,

E.Vallazzab

aDipartimento di Fisica Università di Bari and INFN Sezione di Bari bINFN Sezione di Trieste

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Outline

Introduction

Beam Test Description

Data Analysis and Results

Monte Carlo Simulation

Conclusions

SiTRD SiTRD RR&&DD

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SiTRD SiTRD RR&&DD Introduction

Silicon strip detectors (SSD) with a few tenths of micron of pitch can be combined with a B field to separate the particles from photons in short

distances

i.e. Fabjan NIM 146 (77) 343

High Z gas detectors are typically used to detect TR X-rays

Background = ionization energy loss of radiating particleMeasurements were performed on

the TR spectra using silicon diodes (Li-drifted): a magnetic field separates the radiating particle by TR photons and the Si detector is located a few meters downstream from the radiator

Villa Olmo, Como 15-19 October 2001 F.Giordano 4

SiTRD SiTRD RR&&DD

y TRIGGER:

e-: Pb Č1 Č2 S

-: Pb Č1 Č2 S

Experimental Set-up (CERN-PS)

x

z

x

50 cm 30 cm

yz

Č1 Č2

S1

S2

S3

S4

Pb-Glass

B1T

5 cm C fibers radiator

15 cm

15 cm

B

• Single Side

• Surface area: 3×3 cm2

• Thickness: 300 m

• Strip Pitch: 25 m

• Read-out Pitch: 50 m

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SiTRD SiTRD RR&&DDExperimental Set-up (Photos)

The Cerenkov counters did not work properly during the data taking: no

reliable rejection electron/pion analysis could be performed!

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SiTRD SiTRD RR&&DD The Magnet

B dl = 0.15 Tm

Carbon Fiber Radiator

B field longitudinal profile

15 cm

Distance from centre

B=1T

Separation 34 Strips (Strip Pitch 50 m)

Up to p=30 GeV/c

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SiTRD SiTRD RR&&DD SSD Noise evaluation

ped> 3.6 ADC ch (850 eV)

S/N 100

TR Energy 10 keV

X-rays search cut = 6 ped

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SiTRD SiTRD RR&&DD

Cluster finding to take into account the charge sharing effect:

1.Search of a strip signal > 20 ped

2.Adjacent strips with signal > 10 ped

Events with only one cluster per plane Evaluation of the particle direction by means of the

upstream telescope Projection of the track on the downstream silicon

wafer X-ray search:

1.Track shadow: ± 25 strips around the track projection

2. Looking for a signal > 6ped within the shadow

region

Analysis strategies

Theped refers to single strip RMS pedestal

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SiTRD SiTRD RR&&DD 6 level

20 levelSSD display

X (cm)

0

50

75

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SiTRD SiTRD RR&&DDX-ray position respect to particle

1 GeV/c: 130 Strips 2 GeV/c: 65 Strips

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SiTRD SiTRD RR&&DD Energy Loss & Calibration

The ADC channel distribution is fitted with a Landau function: the most probable value has been set to 80 keV

(S. Hancock et al., Phys. Rev. A 28 (1983) 615)

ADC channels

Nu

mb

er o

f ev

ents

Nu

mb

er o

f ev

ents

Energy loss (keV)

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SiTRD SiTRD RR&&DDA run without radiator @ 2GeV/c

40 (~6%) ghost

X-rays: noisy strips!

669 reconstructed charged particles

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SiTRD SiTRD RR&&DD X-ray Energy Spectra

1 GeV/c “electrons” 2 GeV/c “electrons”

Background

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SiTRD SiTRD RR&&DD

A Monte Carlo code has been developed to simulate the beam test set-up

The MC is based on GEANT 3.21 and HEED The TR process has been included The electronics response has been also taken into account

For more details see:“The Silicon-TRD: A Full Monte-Carlo Simulation” @ the Poster Session

Full Monte Carlo simulation

The simulated data has been analyzed using the same procedure as for real data

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SiTRD SiTRD RR&&DD

1 GeV/c

2 GeV/c

X-ray

Electron

1000 simulated events for each

momentum

MC results

Contamination

10-3 @ e60%

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SiTRD SiTRD RR&&DD Conclusions

A Silicon Strip Detector (SSD) combined with

a magnetic field has been used to detect TR

X-rays

A beam test has demonstrated the feasibility

of the design

A full Monte Carlo code has been developed

to validate the R&D

Further tests and analyses are needed to

better study the detector performance