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11.
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12.
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Design and first measurements of an alternative calorimetry chamber for the HZB quadrupole resonator
/ Keckert, Sebastian (Helmholtz-Zentrum, Berlin) ; Kleindienst, Raphael (Helmholtz-Zentrum, Berlin) ; Knobloch, Jens (Helmholtz-Zentrum, Berlin) ; Kugeler, Oliver (Helmholtz-Zentrum, Berlin)
The systematic research on superconducting thin films requires dedicated testing equipment. The Quadrupole Resonator (QPR) is a specialized tool to characterize the superconducting RF properties of circular planar samples. [...]
CERN-ACC-2015-0115.-
Geneva : CERN, 2015
- Published in :
- Published in : (2015) , pp. TUPB067
Fulltext: PDF;
In : 17th International Conference on RF Superconductivity, Whistler, Canada, 13 - 18 Sep 2015, pp.TUPB067
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13.
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Commissioning results of the HZB quadrupole resonator
/ Kleindienst, Raphael (Helmholtz-Zentrum, Berlin) ; Burrill, Andrew (Helmholtz-Zentrum, Berlin) ; Knobloch, Jens (Helmholtz-Zentrum, Berlin) ; Kugeler, Oliver (Helmholtz-Zentrum, Berlin)
Recent cavity results with niobium have demonstrated the necessity of a good understanding of both the BCS and residual resistance. For a complete picture and comparison with theory, it is essential that one can measure the RF properties as a function of field, temperature, frequency and ambient magnetic field. [...]
CERN-ACC-2015-0114.-
Geneva : CERN, 2015
- Published in : 10.18429/JACoW-SRF2015-WEA1A04
Fulltext: PDF;
In : 17th International Conference on RF Superconductivity, Whistler, Canada, 13 - 18 Sep 2015, pp.WEA1A04
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14.
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Characterization of a superconducting Pb photocathode in a superconducting rf photoinjector cavity
/ Barday, R (Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH) ; Burrill, A (Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH) ; Jankowiak, A (Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH) ; Kamps, T (Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH) ; Knobloch, J (Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH) ; Kugeler, O (Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH) ; Matveenko, A (Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH) ; Neumann, A (Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH) ; Schmeißer, M (Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH) ; Volker, J (Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH) et al.
Photocathodes are a limiting factor for the next generation of ultrahigh brightness photoinjectors. We studied the behavior of a superconducting Pb cathode in the cryogenic environment of a superconducting rf gun cavity to measure the quantum efficiency, its spatial distribution, and the work function. [...]
CERN-ACC-2014-0060.-
Geneva : CERN, 2014
- Published in : Phys. Rev. ST Accel. Beams 16 (2013) 12
Fulltext: PDF;
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15.
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Pathway to a Post Processing Increase in Q0 of SRF Cavities
/ Kugeler, O (Helmholtz-Zentrum, Berlin) ; Vogt, J (Helmholtz-Zentrum, Berlin) ; Knobloch, J (Helmholtz-Zentrum, Berlin) ; Aull, S (CERN ; Siegen U.)
A significant improvement of the quality factor Q0 from values of 1.5x1010 to values around 3x1010 at 1.8 K has been repeatedly achieved in a fully dressed and horizontally operated TESLA type SRF cavity by thermal cycling, i.e. heating the cavity briefly above the 9.2 K transition temperature of niobium and subsequent cooling. [...]
CERN-ACC-2013-0192.-
Geneva : CERN, 2013 - 3 p.
Fulltext: PDF;
In : 4th International Particle Accelerator Conference, Shanghai, China, 12 - 17 May 2013, pp.3129
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16.
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RF Characterization of Niobium Films for Superconducting Cavities
/ Aull† , S (CERN ; University of Siegen, Germany,) ; Calatroni, S (CERN) ; Doebert, S (CERN) ; Junginger, T (CERN) ; Ehiasarian, AP (Sheffield Hallam University, UK) ; Knobloch, J (University of Siegen, Germany ; Helmholtz-Zentrum Berlin, Germany) ; Terenziani, G (CERN ; Sheffield Hallam University, UK)
The surface resistance RS of superconductors shows a complex dependence on the external parameters such as temperature, frequency or radio-frequency (RF) field. The Quadrupole Resonator modes of 400, 800 and 1200 MHz allow measurements at actual operating frequencies of superconducting cavities. [...]
CERN-ACC-2013-0190.-
Geneva : CERN, 2013 - 3 p.
Fulltext: PDF;
In : 4th International Particle Accelerator Conference, Shanghai, China, 12 - 17 May 2013, pp.2399
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17.
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Impact of Trapped Flux and Thermal Gradients on the SRF Cavity Quality Factor
/ Kugeler, O (Helmholtz-Zentrum, Berlin) ; Vogt, J (Helmholtz-Zentrum, Berlin) ; Knobloch, J (Helmholtz-Zentrum, Berlin) ; Aull, S (CERN)
The obtained Q0 value of a superconducting niobium cavity is known to depend on various factors like the RRR of the Niobium material, crystallinity, chemical treatment history, the high-pressure rinsing process, or effectiveness of the magnetic shielding. We have observed that spatial thermal gradients over the cavity length during cool-down appear to contribute to a degradation of Q0. [...]
2012 - 3 p.
- Published in : Conf. Proc.: C1205201 (2012) , pp. WEPPC002
External link: Published from JaCoW
In : 3rd International Particle Accelerator Conference, New Orleans, LA, USA, 20 - 25 May 2012, pp.2203-2205
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18.
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19.
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Electroweak Measurements in Electron-Positron Collisions at W-Boson-Pair Energies at LEP
/ ALEPH Collaboration
Electroweak measurements performed with data taken at the electron-positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3~fb$^{-1}$ collected by the four LEP experiments ALEPH, DELPHI, L3 and OPAL, at centre-of-mass energies ranging from $130~GeV$ to $209~GeV$ [...]
arXiv:1302.3415; CERN-PH-EP-2013-022; CERN-PH-EP-2013-022.-
Geneva : CERN, 2013 - 126 p.
- Published in : Phys. Rep. 532 (2013) 119-244
Draft (restricted): PDF; Fulltext: CERN-PH-EP-2013-022 - PDF; arXiv:1302.3415 - PDF; External link: Preprint
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20.
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