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The Semi conductor activities in the RDD department

The activity :

The department makes silicium detectors adapted to the applications of physics, realized "custom-made product", with specific technologies in the wanted characteristics :

 The group also is involved into a mission of support in the choice of detectors for specific experiments. It intervenes in the design and the integration of industrial detectors by participating in the writing of the specifications of detectors, assures their follow-up, from the order to the reception, also realizes the validation tests in laboratory and participates in the on-site integration of experiment.

The members of the group have the responsibility individually one or several technologies of realization but all have the versatility to make out a will quite typical of detectors Si or Ge.

The tests of maintenance are an integral part of the work of the group and whatever is their origin (internal, partner public or industrialist), detectors are tested before and after experiments.

For that purpose, the group possesses a workshop dedicated to these activities :


Clean room

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Clean room

Starting in January, 2005 with a surface of 12 m ², the room is essentially used to the manipulation of the germanium crystals under laminaire flow (class 100) in an environment with controlled hygrometry close to 30 % of relative humidity. The temperature is also controlled (air-conditioned in 18°C).


Specialized evaporated

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Specialized evaporated

To avoid any surface and volume contamination , four evaporation benches treat each only a single type of element :

  • Golden evaporation (detector with barrier of surface and silicium compensated in lithium)
  • Aluminum evaporation (detector with barrier of surface)
  • Evaporation and distribution of lithium (Silicium compensated in the lithium)
  • Evaporation of oxide (detector with barrier of surface)

Polishing machine

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Polishing machine

The semiconductors workshop has some machine tools which allow to make certain mechanical operations on the Silicium and Germanium crystals. These machines are :

  • A polishing machine
  • A diamond saw for the cuts of Silicium and Germanium patches
  • Two machines with diamond drill to realize circular cuts of Silicium and Germanium, the one for patches with weak thicknesses (< 800 µm) the other one for more thick patches.
  • A drill for the supports of detectors or adaptation of boxes.
Installation for the semiconductors chemical treatments :
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Chemical room

The detectors manufacturing processes require chemical treatments of surface using acids and solvents Two post offices answering safety standards are at the disposal of the department to make detectors. The department has a recycling system of chemical discharges set up in association with the SQE of the laboratory.

Furthermore, the department has a power plant of deionized water. Used for a long time in the department, it was completely completely revised in 2004 and supplies a cleansed of high resistivity water (until 18 occurring in the process of manufacturing of detectors, essentially the cleaning and the rinsing of crystals. The demineralization of the city water is made from a system of three cylinders working on resins of ions exchange.

To know more about it : http:


Spectroscopy alpha, beta, gamma test bench :

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Germanium detector

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Several channels alpha et beta detectors

4 basic installations are available to realize the characterization and the calibration of Silicium and Germanium detectors . Each is equipped with a bench of pumping, with a vacuous chamber, with a chain of spectroscopy (load preamplifier, shaping amplifier , digital analogical converter and of a software of adapted data processing). According to the requests, a more complex system can be realized from these basic installations for specific tests.

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One channel alpha and deta Detector

Contact : A. Torrento



Institut de Physique Nucléaire Orsay - 15 rue Georges CLEMENCEAU - 91406 ORSAY (FRANCE)
UMR 8608 - CNRS/IN2P3

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