NONE-No attached Diamond beamline
Insertion Devices
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Abstract: Studies of novel lattice upgrades for Diamond Light Source to achieve an increase in the number of insertion devices and/or a lower natural emittance are underway (as reported elsewhere at this conference). Such upgrades if carried out progressively would result in successive reductions in storage ring circumference. To maintain synchronous injection then requires the injector system to operate at various frequencies to match these changes. This paper describes the tests carried out with beam, to prove that the injector system of Linac and full energy Booster can be tuned over an extended frequency range.
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May 2013
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NONE-No attached Diamond beamline
Insertion Devices
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Abstract: Diamond plans to operate a 5 m, long period length, APPLE undulator in a long insertion straight section. Theoretical investigations showed a severe impact on machine dynamics especially when the device is operated in vertical polarization mode. The use of local optics corrections and/or lowering of beta functions were initially investigated as possible solutions but with limited success. Active shimming of dynamic multipoles, following the approach at BESSY-II, proved more effective. The optimum shiming has been devised using kick map approach. In this paper we review the theoretical analysis, the commissioning of the active shims and the undulator, and the net effect of the undulator after compensation.
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May 2013
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NONE-No attached Diamond beamline
Accelerator Physics
Diagnostics
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F.
Bakkali Taheri
,
I. V.
Konoplev
,
G.
Doucas
,
A.
Reichold
,
R. J. D. A.
Smith
,
R.
Bartolini
,
N.
Delerue
,
H.
Andrews,
,
N.
Fuster-Martínez
,
C.
Clarke
,
V.
Bharadwaj
,
P. H.
Stoltz
Abstract: There is a significant interest in the development of compact particle accelerators within research areas including X-ray and THz (T-ray) sources of radiation, particle physics and medical sciences. To support the progress in these areas, non-invasive, electron beam diagnostics that are capable of measuring a single femtosecond electron bunch are required. At the current stage such beam diagnostics for femtosecond-long electron bunches are still not available. The goal of the work presented is to understand the spectral characteristics of coherent Smith-Purcell radiation to enable its quick and reliable interpretation including the longitudinal profile reconstruction of electron bunches. The research presented comprises results from numerical modelling and experimental studies. Using the numerical data, we discuss the radiated spectra dependence on the electron bunch profile and analyse the results. We also discuss the experimental data and compare it with theoretical predictions.
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May 2013
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NONE-No attached Diamond beamline
Accelerator Physics
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Abstract: Ultra-low emittance lattices will operate with reduced dynamics apertures. New injection schemes are currently investigated in order to guarantee sufficient injection efficiency. A promising candidate is a pulsed kicker with a nonlinear magnetic field. The studies presented in this paper prove that this kicker allows injection with reduced dynamic aperture and provide minimal perturbation of the stored beam during Top-Up injection. Plans to install such a device at the Diamond light source are outlined.
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May 2013
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NONE-No attached Diamond beamline
Accelerator Physics
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Abstract: Diamond Light Source is investigating the possibility of increasing the storage ring operating current above the nominal 300 mA. A campaign of measurements and simulations has been carried out in order to understand the extent of the parasitic energy loss and characterise the most important items which build up the machine impedance. In this paper we report on the most recent measurements of the longitudinal loss factor and the present status of the impedance database with an initial comparison between the two.
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May 2013
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NONE-No attached Diamond beamline
Insertion Devices
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S.
Gerstel
,
S.
Casalbuoni
,
A. W.
Grau
,
D.
Saez De Jauregui
,
T.
Holubek
,
R.
Voutta
,
R.
Bartolini
,
M. P.
Cox
,
E. C.
Longhi
,
G.
Rehm
,
J. C.
Schouten
,
R.
Walker
,
M.
Migliorati
,
B.
Spataro
Abstract: Understanding the heat load from an electron beam is still an open issue for the cryogenic design of superconducting insertion devices. COLDDIAG, a cold vacuum chamber for diagnostics was designed and built specially for this purpose. With the equipped instrumentation, which covers temperature sensors, pressure gauges, mass spectrometers as well as retarding field analyzers it is possible to measure the beam heat load, total pressure, and gas content as well as the net flux and energy of particles hitting the chamber walls. Following a failure after its first installation in November 2011, COLDDIAG was subsequently reinstalled in the Diamond storage ring in August 2012. We report on the preliminary results that have been obtained since then.
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May 2013
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NONE-No attached Diamond beamline
Accelerator Physics
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J.
Clarke
,
D.
Angal-Kalinin
,
N.
Bliss
,
R.
Buckley
,
S.
Buckley
,
R.
Cash
,
P.
Corlett
,
L.
Cowie
,
G.
Cox
,
G. P.
Diakun
,
D. J.
Dunning
,
B. D.
Fell
,
A.
Gallagher
,
P.
Goudket
,
A. R.
Goulden
,
D. M. P.
Holland
,
S. P.
Jamison
,
J. K.
Jones
,
A. S.
Kalinin
,
B. P. M.
Liggins
,
L.
Ma
,
K. B.
Marinov
,
B.
Martlew
,
P. A.
Mcintosh
,
J. W.
Mckenzie
,
K. J.
Middlemen
,
B. L.
Militsyn
,
A. J.
Moss
,
B. D.
Muratori
,
M. D.
Roper
,
R.
Santer
,
Y.
Saveliev
,
E.
Snedden
,
R. J.
Smith
,
S. L.
Smith
,
M.
Surman
,
T.
Thakker
,
N. R.
Thompson
,
R.
Valizadeh
,
A. E.
Wheelhouse
,
P. H.
Williams
,
R.
Bartolini
,
I.
Martin
,
R.
Barlow
,
A.
Kolano
,
G.
Burt
,
S.
Chattopadhyay
,
D.
Newton
,
A.
Wolski
,
R. B.
Appleby
,
H. L.
Owen
,
M.
Serluca
,
G.
Xia
,
S.
Boogert
,
A.
Lyapin
,
L.
Campbell
,
B. W. J.
Mcneil
,
V. V.
Paramonov
Abstract: The conceptual design of CLARA, a novel FEL test facility focussed on the generation of ultrashort photon pulses with extreme levels of stability and synchronisation is described. The ultimate aim of CLARA is to experimentally demonstrate, for the first time, that sub-coherence length pulse generation with FELs is viable. The results will translate directly to existing and future X-Ray FELs, enabling them to generate attosecond pulses, thereby extending the science capabilities of these intense light sources. This paper will describe the design of CLARA, pointing out the flexible features that will be incorporated to allow multiple novel FEL schemes to be proven.
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May 2013
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NONE-No attached Diamond beamline
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Abstract: The electronic structure of curium metal has been investigated by valence-band and 4f core-level photoemission spectroscopy using a high-purity Cm 248 sample. The experimental spectra are dominated by poorly screened features and indicate full localization of the 5f electrons, in strong contrast to the lighter actinides, including Pu and Am. The results obtained are in good agreement with the Cm photoemission obtained by atomic multielectronic calculations for a 5f 7 configuration and with the total 5f density of states calculated ab initio within a correlated band theory model based on the self-consistent, local-density-matrix approximation to the dynamical mean-field theory.
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Mar 2011
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NONE-No attached Diamond beamline
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Open Access
Abstract: Secondary active transporters move molecules across cell membranes by coupling this process to the energetically favourable downhill movement of ions or protons along an electrochemical gradient. They function by the alternating access model of transport in which, through conformational changes, the substrate binding site alternately faces either side of the membrane. Owing to the difficulties in obtaining the crystal structure of a single transporter in different conformational states, relatively little structural information is known to explain how this process occurs. Here, the structure of the sodium-benzylhydantoin transporter, Mhp1, from Microbacterium liquefaciens, has been determined in three conformational states; from this a mechanism is proposed for switching from the outward-facing open conformation through an occluded structure to the inward-facing open state.
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Dec 2010
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NONE-No attached Diamond beamline
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Abstract: The rate at which X-ray structures of membrane proteins are solved is on a par with that of soluble proteins in the late 1970s. There are still many obstacles facing the membrane protein structural community. Recently, there have been several technical achievements in the field that have started to dramatically accelerate structural studies. Here, we summarize these so-called ‘tricks-of-the-trade’ and include case studies of several mammalian transporters.
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Jun 2010
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