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Your search keyword '"Schmoekel, M."' showing total 10 results
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10 results on '"Schmoekel, M."'

1. High gradients at SRF photoinjector cavities with low RRR copper cathode plug screwed to the cavity back wall

Author

Vogel, E., Sekutowicz, J., Bazyl, D., Büttner, T., van der Horst, B., Iversen, J., Klinke, D., Muhs, A., Reschke, D., Sägebarth, S., Schilling, P., Schmökel, M., Steder, L., Thie, J. -H., Weise, H., and Wiencek, M.

Subjects
Physics - Accelerator Physics
Abstract

In recent years we increased the typical maximum peak field on axis gradients obtained in L-band superconducting RF (SRF) photoinjector cavities at vertical tests to around 55 MV/m. This was achieved with niobium cathode plugs directly screwed to the cavity back wall omitting an RF choke filter and a load lock system for cathodes. Copper demonstrated being a suitable cathode material in normal conducting injector cavities used at X-Ray Free Electron Lasers (XFELs) operating with pulsed RF. In this article we present the first experimental confirmation that peak field on axis gradients around 55 MV/m and beyond can be achieved in L-band SRF photoinjector cavities with copper cathode plugs screwed to the cavity back wall. We view this as a major milestone for the development of a high gradient photoinjector operating continuous wave (CW)., Comment: 4 pages, 7 figures, to be submitted to PRAB

Published
2023

2. SRF gun development at DESY

Author

Vogel, E., Sekutowicz, J., Barbanotti, S., Hartl, I., Jensch, K., Klinke, D., Kostin, D., Moeller, W.-D., Schmoekel, M., Sievers, S., Steinhau-Kuehl, N., Sulimov, A., Thie, J.-H., Horst, B., Weise, H., Winkelmann, L., Smedley, J., Teichert, J., Wiencek, M., Lorkiewicz, J. A., Nietubyc, R., Vogel, E., Sekutowicz, J., Barbanotti, S., Hartl, I., Jensch, K., Klinke, D., Kostin, D., Moeller, W.-D., Schmoekel, M., Sievers, S., Steinhau-Kuehl, N., Sulimov, A., Thie, J.-H., Horst, B., Weise, H., Winkelmann, L., Smedley, J., Teichert, J., Wiencek, M., Lorkiewicz, J. A., and Nietubyc, R.

Abstract

A future upgrade of the European XFEL (E-XFEL) foresees an additional CW operation mode, which will increase the flexibility in the photon beam time structure [1, 2, 3]. One of the challenges of this operational mode is the need for a CW operating photo injector. We believe that using an SRF gun is the preferred approach as the beam parameters of normal conducting pulsed guns can be potentially met by SRF guns operating CW. For more than a decade DESY, in collaboration with TJNAF, NCBJ, BNL, HZB and HZDR, has performed R&D to develop an all superconducting RF gun with a lead cathode. In the frame of E-XFEL CW upgrade feasibility studies, the SRF-gun R&D program gained more attention and support. Within the next few years we would like to demonstrate the performance of the all superconducting injector required for the E-XFEL upgrade. The selected approach offers advantages w.r.t. the cleanliness of the superconducting surface, but requires a complete disassembly of a cryostat and stripping the gun cavity in a clean room to exchange the cathode. Thus it is practical only when the life time of the cathode is at least several months. In this paper we present the actual status of the R&D program, next steps and the longer term plans.

Published
2019

3. SRF gun development at DESY

Author

Vogel, E., Sekutowicz, J., Barbanotti, S., Hartl, I., Jensch, K., Klinke, D., Kostin, D., Moeller, W.-D., Schmoekel, M., Sievers, S., Steinhau-Kuehl, N., Sulimov, A., Thie, J.-H., Horst, B., Weise, H., Winkelmann, L., Smedley, J., Teichert, J., Wiencek, M., Lorkiewicz, J. A., Nietubyc, R., Vogel, E., Sekutowicz, J., Barbanotti, S., Hartl, I., Jensch, K., Klinke, D., Kostin, D., Moeller, W.-D., Schmoekel, M., Sievers, S., Steinhau-Kuehl, N., Sulimov, A., Thie, J.-H., Horst, B., Weise, H., Winkelmann, L., Smedley, J., Teichert, J., Wiencek, M., Lorkiewicz, J. A., and Nietubyc, R.

Abstract

A future upgrade of the European XFEL (E-XFEL) foresees an additional CW operation mode, which will increase the flexibility in the photon beam time structure [1, 2, 3]. One of the challenges of this operational mode is the need for a CW operating photo injector. We believe that using an SRF gun is the preferred approach as the beam parameters of normal conducting pulsed guns can be potentially met by SRF guns operating CW. For more than a decade DESY, in collaboration with TJNAF, NCBJ, BNL, HZB and HZDR, has performed R&D to develop an all superconducting RF gun with a lead cathode. In the frame of E-XFEL CW upgrade feasibility studies, the SRF-gun R&D program gained more attention and support. Within the next few years we would like to demonstrate the performance of the all superconducting injector required for the E-XFEL upgrade. The selected approach offers advantages w.r.t. the cleanliness of the superconducting surface, but requires a complete disassembly of a cryostat and stripping the gun cavity in a clean room to exchange the cathode. Thus it is practical only when the life time of the cathode is at least several months. In this paper we present the actual status of the R&D program, next steps and the longer term plans.

Published
2018

4. Integration of the European XFEL Accelerating Modules

Author

Vogel, E., Barbanotti, S., Branlard, J., Brueck, H., Choroba, S., Hagge, L., Jensch, K., Katalev, V.V., Kostin, D., Käfer, D., Lilje, L., Matheisen, A., Moeller, W.-D., Noelle, D., Petersen, B., Prenting, J., Reschke, D., Schlarb, H., Schmoekel, M., Sekutowicz, J.K., Singer, W., Weise, H., Berry, S., Madec, C., Napoly, O., Visentin, B., Borowiec, P., Swierblewski, J., Bosotti, A., Michelato, P., Kaabi, W., Plawski, E.P., Toral, F., Deutsches Elektronen-Synchrotron [Hamburg] (DESY), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, XFEL - Dept. Accelerateurs, Laboratoire de l'Accélérateur Linéaire (LAL), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
XFEL, [PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph]
Abstract

mopb017 - ISBN 978-3-95450-122-9; International audience; The production of the 103 superconducting accelerating modules for the European XFEL is an international effort.

Published
2012

7. Preparatory procedure and equipment for the European x-ray free electron laser cavity implementation

Author

Reschke, D., primary, Bandelmann, R., additional, Buettner, T., additional, Escherich, K., additional, Goessel, A., additional, v.d.Horst, B., additional, Iversen, J., additional, Klinke, D., additional, Kreps, G., additional, Krupka, N., additional, Lilje, L., additional, Matheisen, A., additional, Moeller, W.-D., additional, Zimmermann, H. Morales, additional, Mueller, C., additional, Petersen, B., additional, Proch, D., additional, Schmoekel, M., additional, Steinhau-Kuehl, N., additional, Thie, J.-H., additional, Weise, H., additional, Weitkaemper, H., additional, Carcagno, R., additional, Khabiboulline, T. N., additional, Kotelnikov, S., additional, Makulski, A., additional, Nogiec, J., additional, Nehring, R., additional, Ross, M., additional, and Schappert, W., additional

Published
2010
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9. S1-Global module tests at STF/KEK

Author

Bosotti, A., Pagani, C., Paparella, R., Pierini, P., Jensch, K., Kostin, D., Lilje, L., Matheisen, A., Moeller, W. -D, Schilling, P., Schmoekel, M., Walker, N., Weise, H., Arkan, T., Barbanotti, S., Battistoni, M., Carter, H., Champion, M., Hocker, A., Kephart, R., Kerby, J., Mitchell, D., Peterson, J., Pischalnikov, Y., Ross, M., Schappert, W., Smith, B., Adolphsen, C., Nantista, C., Akemoto, M., Fukuda, S., Hara, K., Hayano, H., Higashi, N., Kako, E., Katagiri, H., Kojima, Y., Kondo, Y., Matsumoto, T., Matsushita, H., Michizono, S., Miura, T., Hirotaka NAKAI, Nakajima, H., Nakanishi, K., Noguchi, S., Ohuchi, N., Saeki, T., Satoh, M., Shishido, T., Shidara, T., Takenaka, T., Terashima, A., Toge, N., Tsuchiya, K., Watanabe, K., Yamaguchi, S., Yamamoto, A., Yamamoto, Y., Yokoya, K., and Yoshida, M.

10. Chemical bonding in a linear chromium metal string complex.

Author

Wu LC, Thomsen MK, Madsen SR, Schmoekel M, Jørgensen MR, Cheng MC, Peng SM, Chen YS, Overgaard J, and Iversen BB

Abstract

A combined experimental and theoretical electron density study of the shortest trichromium metal wire, Cr3(dpa)4Cl2·(C2H5OC2H5)(x)(CH2Cl2)(1-x) (1, dpa = bis(2-pyridyl)amido), is reported. High resolution X-ray diffraction data has been collected both at 100 K using a conventional X-ray source (DS1) and at 15 K using a synchrotron X-ray source (DS2). The linear chromium string is terminated by Cl(-) ions at both ends, and each Cr atom is also coordinated by four N atoms from bridging dpa ligands. The two Cr-Cr bond distances are unequal at 100 K (with d(Cr1-Cr2) being 0.029 Å shorter than d(Cr2-Cr3)) but at 15 K they are almost equal (0.002 Å difference). Analysis of the slightly elongated thermal ellipsoids of the Cr2 atom suggests that it is not due to disorder, but the presence of a shallow potential energy surface. Laplacian maps clearly show local valence shell charge concentration (VSCC) in the electron density along the bisector of the equatorial Cr-N bonds. Integration over the atomic basins indicates that Cr2 has smaller atomic charge and volume than Cr1 and Cr3. The topological characterization of the Cr-Cr bonds indicates partly covalent characters with electron density at the bond critical point of ∼0.3 e Å(-3) and negative total energy density. The delocalization index of Cr-Cr is 0.8 for Cr1-Cr2 and 0.08 for Cr1-Cr3. Second-order perturbation analysis shows high stabilization energy of the Cr-Cr bonds (E(2) ∼ 190 kcal mol(-1)). Delocalization indices and source function and natural bond orbital analyses are all indicative of localized Cr-Cr bonding interactions.

Published
2014
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