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Mechanical and Fluidic Integration of Scintillating Microfluidic Channels into a Detector System

Context

Scintillators are materials that produces photons when exposed to particle

radiation. They are the active material of several particle detectors used in

the LHC, at CERN. Long exposition to the radiations will cause a light

output decrease and result eventually in a replacement of the detector.

This problem leaded a group of CERN

engineers and scientists to develop a new

microfluidic detector, where the damaged

liquid scintillator could be replaced by

pumping in order to increase the detector’s

lifetime. The aim of the project was to

circulate the liquid in the microchannels

for the first time and to investigate the pumping effects on the scintillator’s

light intensity.

Scintillating microfluidic channels for particle

detectors

Two main potential applications:

- Single particle tracking to know the

position of each particle

- Beam monitoring to know the global

energy distribution of the particle beam

Two main fields of application :

- High energy particle experiment as in the LHC

- Hadron-therapy : Alternative way to destruct tumor cells using particles

Liquid scintillator radiation damage

characterization

The development of a pumping system for the two potential applications

required more information concerning the radiation damage of the liquid

scintillator. An experiment was then planned to expose the liquid

scintillator to a proton beam and to characterize the scintillation decrease.

Temperature dependence of the scintillation

efficiency

The pumping of the liquid scintillator

in the microchannels could be

combined to a cooling process in

order to increase the detector’s

efficiency. A preliminary experiment

was then conducted to determine if

the scintillator used was subjected,

like other ones, to a temperature

dependence.

Author

Davy Brouzet

LAMD Laboratoire de Conception

Mécanique Appliquée

Pumping applied to the microchannels (1)

A whole chemically-resistant system was designed to connect a syringe to

various experiments related to the development of the microfluidic

detectors, including the ones carried out during this project.

Damaging the liquid using the photobleaching effect and pumping it

thanks to a syringe pump, the scintillator’s recovery in the microchannels

was proven experimentally.

Supervisors

Alessandro Mapelli

Pietro Maoddi

Prof. Jürg Schiffmann

Acknowledgements

Mikhail Asiatici

All the MicroScint project people

Pumping applied to the microchannels (2)

The flow rate/light output dependence and the possible light output

difference between the microchannels was also investigated

Principle of a

particle detector

Typical

microchannels

Preliminary results tend to

show a temperature

dependence of the scintillator

of a few percent per ten

degrees.

Temperature

dependence

experiment