Investigation of superconductive materials Overview

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Investigation of superconductive materials
Overview
STREGA JRA3WP 1 - Task M3

• Renzo F. Parodi
• INFN-Genova

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Collaboration

• The INFN_Genoa Group is the only Group involved
  in the development of the M3-Task.

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Long Term Aim

• An innovative detector based on superconducting
  resonant cavities has been proposed.
• A key feature of this detection scheme is the
  very high electromagnetic quality factor that can
  be obtained in superconducting structures.
• The aim is to build cavities using the technique
  of niobium sputtering on a substrate having high
  thermal conductivity and low intrinsic mechanical
  dissipations.
• The proof of feasibility of the detector will be
  essential for the development of advanced
  superconducting RF detectors with high
  sensitivity.

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Short Term Applications

• Superconducting RF cavities are Highly suitable
  to build RF parameric transducers for Acoustic
  detectors.
• Superconducting RF Cavities can generate fields
  in the 107 V/m with power dissipation compatible
  with Ultra-cryogenic operation (.11 mW).
• The high operating frequencies, and the
  development of Cryogenic RF electronics in
  telecommunications, gives of the shelf
  amplifiers with Noise temperature ten times the
  quantum limit.
• The results already obtained in M3 are the basis
  for the production of an RF parametric transducer
  to be considered as possible readout on the ROG
  Sphere.

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Design sensitivity
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hmin ? 6 x 10-21 h lt 10-20 over 400 Hz
(-1/2)
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Hz
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(1/2)
hh
S
-21
10
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Frequency Hz
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Task M3 ActivitiesFull project
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Task M3 Activitiesfirst 36 months
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Production of seamless copper cavities

• Three copper cavity are built.
• Starting from a seamless copper tube
• By spinning on a collapsible mandrel

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Seamless cavity production
Collapsible spinning mandrel (Enzo Palmieri)
INFN-LNL
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Seamless cavity production
Three cavity are ready
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Seamless cavity production
One of the cavities is Today used to test the
sputtering setup for the Niobium sputtering film
deposition process. The first cavity is usedas a
test bed to produce niobium samples at different
cavity places The samples are measured for Tc
and Bc
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Niobium Sputtering

• Since the Higher the RF Qel the better is the
  sensitivity, niobium is the best material for the
  application. (Qel 1011 already achieved)
• Niobium is also a good material from the
  mechanical point of view (low mechanical losses),
  but very expensive.
• The Low Thermal conductivity when superconducting
  is also a big problem in our application.
• Sputtered niobium films on high thermal
  conductivity and low mechanical losses material
  are the solution (when proven successful)

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Niobium Film OptimizationCritical Temperature Tc
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Niobium Film OptimizationCritical Field Bc
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Niobium critical field
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Mechanical characterisation of Substrata

• The work is under way
• We measured the Mechanical properties of the
  first cavity prototypes.
• The test setup is ready and tested
• Next step will be the measurement of the niobium
  and niobium on copper samples and cavities from
  room temperature to superfluid helium (1.85K).