Status report on MURAY telescope R&D

Status report on MURAYtelescope R&D

Pasquale Noli

on behalf of Mu-Ray collaboration

Outline

•Motivation

•Measurement principles

•The MURAY telescope

–Fiber optical connector

–SiPM hybrid connector

–SiPM from IRST-FBK test

–Front End electronic and DAQ

•Conclusions

23/09/2010

SIF 2010 Bologna

300

200

Conduit length =8000m

Gas content = 5 wt%

1631eruption

Pompeieruption

100,000 ton/s

100

Motivation

Volcano-eruption dynamics mostly depend on

• the gas content

•the chemical composition of the magma

•the lava-conduit dimensions and shape.

Seismic,

gravimetric,

electromag.

methods:

Several km

Muon radiography:few hundreds m

Traditional measurement methods :

• gravimetric

• seismological

• electromagnetic

Have spatial resolutions of the order of severalhundredmeters.

Muonradiographycan improve resolutions

by one order of magnitude.

Simulated Mass eruption rate vs. ConduitSimulated Mass eruption rate vs. Conduit

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Muon Radiography

•Muon radiography is based on the measurement of theabsorption of cosmic muons inside matter.

“The first application was realized in 1971 by Alvarez andcollaborators for the search of unknown burial cavities in theChephren pyramid.”

•In recent years Tanaka and collaborators, from University ofTokyo, have demonstrated the possibility to use thistechnique, to study the internal structure of volcanoes.

•The spatial resolution that can be obtained with this methodis of the order of 10 m.

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SIF 2010 Bologna

Measurement principles (I)(No background hypothesis)

•The observed number of muons is a function of the muonflux crossing the volcano volume seen along the direction(,) the absorption factor A, and the detector efficiency  :

•In the limit of neglecting the  dependence of cosmic ray flux,the product of the muonflux times detector efficiency can bemeasured using special runs pointing to “free” sky region

• Then the absorption can be evaluated as:

23/09/2010

SIF 2010 Bologna

Measurement principles (II)

•Starting from the theoretical muon flux distribution f (Thompson andWhalley expression) , we compute the expected muon transmissionrate through water meter equivalent for each  direction.

•For each (θ,) direction we can obtain the mean rock density fromthe ratio between:

– the water meter equivalent length relative to A.

–thickness of montain.

23/09/2010

SIF 2010 Bologna

The MURAY telescope (I)

Two 2x2 m2 X-Y stations

$C:\Users\Pasquale\Dati applicazioni\Desktop\Foto_lab_MuRay\P2100065.JPG$

• Triangular shape scintillators (from Fermilab)

•Scint. light collected by WLS one-side mirrored fiber

(BCF92 fast response fibers from Bicron)

• Dedicated 32 fibers optical connector

• Dedicated SiPM from FBK-IRST .

They have 1.4 mm diameter and 70x70 m2

cell size, with 292 cells in total

• Dedicated hybrid hosting 32 SiPMs

•SiPM temperature control by Peltier Cells

• SPIROC 0 ASIC FEE (from Orsay group)

• Dedicated read-out and acquisition board

Expected performances:

• ≈3 mm space resolution (by measurement of

charge sharing between two adjacent strips)

• ≈ 1ns time resolution

• O(10) W power consumption

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SIF 2010 Bologna

The MURAY telescope (II)

2 m

32 scintillator bars module (0.5 m large), with barsglued together and on a G11 fiberglass support plate

Fibers’ connector

SiPM hybrid connector

0.5 m

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SIF 2010 Bologna

The MURAY telescope prototype (I)

A prototype is under construction

• 3 X-Y stations 1x1 m2 area

• SPIROC 1 ASIC FEE

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SIF 2010 Bologna

A special tool designed and built for precision assembly of the 32 bars in a plane

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Fiber optical connector

A special connector (made of black Plexiglas) has been developed for high-precisionpositioning of the fibers in front of the SiPMs.

32 fibers are glued on the connector that will be fixed to the module chassis.

The fiber connector is mechanically coupled with a hybrid circuit hosting the SiPMs.

MAGNIFICATION OF THE GLUE TANKS

SIPM SIDE

FIBER SIDE

O RING SEAT

Al PROTOTIPE

Reference hole

$C:\Users\Pasquale\Dati applicazioni\Desktop\Materiale per Orsey\Foto\DSCN1438.JPG$

Al prototype

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SIF 2010 Bologna

SiPM hybrid connector

In order to optimize the cooling by Peltier cells, we decided to group together

32 die SiPM in a single PCB.

One side of the Peltier cells is thermally in contact with the back side of the PCB.

A rubber O-ring ensures light and air tightness.

Two temperature sensors are located on the PCB for the Peltier cells control circuit.

The first 5 hybrid PCB have been produced in Florence.

$C:\Users\Pasquale\Dati applicazioni\Desktop\Materiale per Orsay\Foto\DSCN1457.JPG$

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SIF 2010 Bologna

First test on SiPM

We studied the V break-down of the SiPM of first hybrid connector.

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SIF 2010 Bologna

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Front End electronic and DAQ (I)

Spiroc 1: we have 18 chips, enough for the 1x1 m2 prototype

The FE board (Slave) and the trigger-DAQ board (Master) have been designed. The firstprototypes have been realized and are under test.

MASTER

SLAVE

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SIF 2010 Bologna

Conclusions

•We are presently assembling the first MU-RAY prototypemodule

•The SiPMs produced at IRST-FBK are assembled on hybridconnector and are under test in Naples.

•A special optical connector with SiPMs and Peltiercooling hasbeen designed and built.

•The readout electronics has been designed and is under test.

23/09/2010

SIF 2010 Bologna