study of mgb 2 thin films on nb by pulse laser deposition s.mitsunobu, s.inagaki, h.nakanishi,...
TRANSCRIPT
Study of MgB2 Thin Films on Nb by Pulse Laser Deposition
S.Mitsunobu, S.Inagaki, H.Nakanishi, M.Wake and M.Fukutomi*
KEK,NIMR*
Scope of talkScope of talk
IntroductionIntroduction
Forming method Mgb2 thin filmForming method Mgb2 thin film PLD equipment PLD equipment Precursor annealing Precursor annealing
RF Measurement of the MgB2 thin film and NbRF Measurement of the MgB2 thin film and Nb
Measurement of photo electron from the MgB2 thin Measurement of photo electron from the MgB2 thin film and Nbfilm and Nb
SummarySummary
INTRODUCTION
The large efforts have been concentrated on Nb cavities for International Linear Collider (ILC). The maximum accelerating field gradient of Nb cavities is limited about 50 MV/m due to Hcsh. MgB2 have higher Tc than Nb and expected to have higher Hcsh. Thin films of MgB2 on Nb is useful to increase future ILC energy upgrading.
At KEK, the preliminary test of thin films on Nb by Pulse Laser Deposition(PLD) method have been started and initially the direct deposition
of MgB2 film on Nb was studied.
QLs of MgB2 film on Nb & Nb
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Temp ( K)
QL QL(MgB2-Nb)
QL(Nb)
QL for Nb & MgB2 film
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Temp ( K)
QL QL(MgB2-Nb)
QL(Nb)
Summery
• MgB2 precursor films formed on Nb by PLD.• The precursor film annealed at 620oC. • Cold RF measurement have been done.• The film partially superconducting.• Preliminary, photo electrons were measured for
Nb and MgB2. Some damaging of MgB2 surface was induced by defocused laser beam.
• More study will be continued.