Detectors
|
J.
Correa
,
M.
Mehrjoo
,
R.
Battistelli
,
F.
Lehmkühler
,
A.
Marras
,
C. B.
Wunderer
,
T.
Hirono
,
V.
Felk
,
F.
Krivan
,
S.
Lange
,
I.
Shevyakov
,
V.
Vardanyan
,
M.
Zimmer
,
M.
Hoesch
,
K.
Bagschik
,
N.
Guerrini
,
B.
Marsh
,
I.
Sedgwick
,
G.
Cautero
,
L.
Stebel
,
D.
Giuressi
,
R. H.
Menk
,
A.
Greer
,
T.
Nicholls
,
W.
Nichols
,
U.
Pedersen
,
P.
Shikhaliev
,
N.
Tartoni
,
H. J.
Hyun
,
S. H.
Kim
,
S. Y.
Park
,
K. S.
Kim
,
F.
Orsini
,
F. J.
Iguaz
,
F.
Büttner
,
B.
Pfau
,
E.
Plönjes
,
K.
Kharitonov
,
M.
Ruiz-Lopez
,
R.
Pan
,
S.
Gang
,
B.
Keitel
,
H.
Graafsma
Open Access
Abstract: The PERCIVAL detector is a CMOS imager designed for the soft X-ray regime at photon sources. Although still in its final development phase, it has recently seen its first user experiments: ptychography at a free-electron laser, holographic imaging at a storage ring and preliminary tests on X-ray photon correlation spectroscopy. The detector performed remarkably well in terms of spatial resolution achievable in the sample plane, owing to its small pixel size, large active area and very large dynamic range; but also in terms of its frame rate, which is significantly faster than traditional CCDs. In particular, it is the combination of these features which makes PERCIVAL an attractive option for soft X-ray science.
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Jan 2023
|
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Detectors
|
Alessandro
Marras
,
Jonathan
Correa
,
Sabine
Lange
,
Vahagn
Vardanyan
,
Tim
Gerhardt
,
Manuela
Kuhn
,
Frantisek
Krivan
,
Igor
Shevyakov
,
Manfred
Zimmer
,
Moritz
Hoesch
,
Kai
Bagschik
,
Frank
Scholz
,
Niccolo
Guerrini
,
Ben
Marsh
,
Iain
Sedgwick
,
Giuseppe
Cautero
,
Dario
Giuressi
,
Gregori
Iztok
,
Ralf H.
Menk
,
Martin
Scarcia
,
Luigi
Stebel
,
Tim
Nicholls
,
William
Nichols
,
Ulrik K.
Pedersen
,
Polad
Shikhaliev
,
Nicola
Tartoni
,
Hyojung
Hyun
,
Seonghan
Kim
,
Kyungsook
Kim
,
Seungyu
Rah
,
Arkadiusz
Dawiec
,
Fabienne
Orsini
,
Giovanni
Pinaroli
,
Alan
Greer
,
Steve
Aplin
,
April D.
Jewell
,
Todd J.
Jones
,
Shouleh
Nikzad
,
Michael E.
Hoenk
,
Frank
Okrent
,
Heinz
Graafsma
,
Cornelia B.
Wunderer
Open Access
Abstract: In this paper the back-side-illuminated Percival 2-Megapixel (P2M) detector is presented, along with its characterization by means of optical and X-ray photons. For the first time, the response of the system to soft X-rays (250 eV to 1 keV) is presented. The main performance parameters of the first detector are measured, assessing the capabilities in terms of noise, dynamic range and single-photon discrimination capability. Present limitations and coming improvements are discussed.
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Jan 2021
|
|
B18-Core EXAFS
|
Open Access
Abstract: Lithium‐rich transition metal cathodes can deliver higher capacities than stoichiometric materials by exploiting redox reactions on oxygen. However, oxidation of O2− on charging often results in loss of oxygen from the lattice. In the case of Li2MnO3 all the capacity arises from oxygen loss, whereas doping with Ni and/or Co leads to the archetypal O‐redox cathodes Li[Li0.2Ni0.2Mn0.6]O2 and Li[Li0.2Ni0.13Co0.13Mn0.54]O2, which exhibit much reduced oxygen loss. Understanding the factors that determine the degree of reversible O‐redox versus irreversible O‐loss is important if Li‐rich cathodes are to be exploited in next generation lithium‐ion batteries. Here it is shown that the almost complete eradication of O‐loss with Ni substitution is due to the presence of a less Li‐rich, more Ni‐rich (nearer stoichiometric) rocksalt shell at the surface of the particles compared with the bulk, which acts as a self‐protecting layer against O‐loss. In the case of Ni and Co co‐substitution, a thinner rocksalt shell forms, and the O‐loss is more abundant. In contrast, Co doping does not result in a surface shell yet it still suppresses O‐loss, although less so than Ni and Ni/Co doping, indicating that doping without shell formation is effective and that two mechanisms exist for O‐loss suppression.
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Aug 2020
|
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Detectors
|
I.
Sedgwick
,
F.
Krivan
,
I.
Shevyakov
,
M.
Zimmer
,
H.
Graafsma
,
G.
Cautero
,
D.
Giuressi
,
R.
Menk
,
G.
Pinaroli
,
L.
Stebel
,
A.
Greer
,
N.
Guerrini
,
U.
Pedersen
,
N.
Tartoni
,
S. Y.
Rah
,
H. J.
Hyun
,
K. S.
Kim
,
S. H.
Kim
,
B.
Boitrelle
,
F
Orsini
,
B.
Marsh
,
T.
Nicholls
,
A.
Marras
,
C. B.
Wunderer
,
J.
Correa
,
S.
Lange
,
M.
Kuhn
Abstract: High brilliance synchrotrons and Free Electron Lasers (FELs) require high performing detector systems to realise their full potential. High dynamic range, low noise and high frame rate are all of great importance. In this paper we describe the P2M CMOS sensor, designed for soft X-ray detection at such facilities. We refer to previous work on test devices demonstrating a noise of <16e-, a full well capacity of >5Me- and quantum efficiency of >80% at 400eV (and with good sensitivity even below this value). Initial test results on the first Front Side Illuminated (FSI) 2 Megapixel device are also presented, and an outline of future work is described.
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Nov 2019
|
|
I09-Surface and Interface Structural Analysis
|
Andrew J.
Naylor
,
Eszter
Makkos
,
Julia
Maibach
,
Niccolo
Guerrini
,
Adam
Sobkowiak
,
Erik
Bjorklund
,
Juan G.
Lozano
,
Ashok
Sreekumar Menon
,
Reza
Younesi
,
Matthew R.
Roberts
,
Kristina
Edström
,
M. Saiful
Islam
,
Peter G.
Bruce
Diamond Proposal Number(s):
[14733, 16629]
Open Access
Abstract: Lithium-rich materials, such as Li1.2Ni0.2Mn0.6O2, exhibit capacities not limited by transition metal redox, through the reversible oxidation of oxide anions. Here we offer detailed insight into the degree of oxygen redox as a function of depth within the material as it is charged and cycled. Energy-tuned photoelectron spectroscopy is used as a powerful, yet highly sensitive technique to probe electronic states of oxygen and transition metals from the top few nanometers at the near-surface through to the bulk of the particles. Two discrete oxygen species are identified, On- and O2-, where n<2, confirming our previous model that oxidation generates localised hole states on O upon charging. This is in contrast to the oxygen redox inactive high voltage spinel LiNi0.5Mn1.5O4, for which no On- species is detected. The depth profile results demonstrate a concentration gradient exists for On- from the surface through to the bulk, indicating a preferential surface oxidation of the layered oxide particles. This is highly consistent with the already well-established core-shell model for such materials. Ab initio calculations reaffirm the electronic structure differences observed experimentally between the surface and bulk, while modelling of delithiated structures shows good agreement between experimental and calculated binding energies for On-.
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Sep 2019
|
|
Detectors
|
C. B.
Wunderer
,
J.
Correa
,
A.
Marras
,
S.
Aplin
,
B.
Boitrelle
,
P.
Goettlicher
,
F.
Krivan
,
M.
Kuhn
,
S.
Lange
,
M.
Niemann
,
F.
Okrent
,
I.
Shevyakov
,
M.
Zimmer
,
N.
Guerrini
,
B.
Marsh
,
I.
Sedgwick
,
G.
Cautero
,
D.
Giuressi
,
I.
Gregori
,
G.
Pinaroli
,
R.
Menk
,
L.
Stebel
,
A.
Greer
,
T.
Nicholls
,
U. K.
Pedersen
,
N.
Tartoni
,
H.
Hyun
,
K.
Kim
,
S.
Rah
,
H.
Graafsma
Abstract: The peak brilliance reached by today's Free-Electron Laser and Synchrotron light sources requires photon detectors matching their output intensity and other characteristics in order to fully realize the sources' potential. The Pixellated Energy Resolving CMOS Imager, Versatile And Large (Percival) is a dedicated soft X-ray imager (0.25–1 keV) developed for this purpose by a collaboration of DESY, Rutherford Appleton Laboratory/STFC, Elettra Sincrotrone Trieste, Diamond Light Source, and Pohang Accelerator Laboratory. Following several generations of prototypes, the Percival "P2M" 2-Megapixel imager—a 4.5×5 cm monolithic, stitched sensor with an uninterrupted imaging area of 4×4 cm2 (1408×1484 pixels of 27×27 μm—was produced and has demonstrated basic functionality with a first-light image using visible light. It is currently being brought to full operation in a front-illuminated configuration. The readout system being commissioned in parallel has been developed specifically for this imager which will produce—at full 300 Hz frame rate—data at 20 Gbit/s. A first wafer with eight Percival P2M chips has undergone backthinning to enable soft X-ray detection. It has been diced and chips are currently being wirebonded. We summarize here the P2M system, the project status, and show the P2M sensor's first response to visible light.
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Jan 2019
|
|
I10-Beamline for Advanced Dichroism
Detectors
|
Alessandro
Marras
,
Cornelia
Wunderer
,
Jonathan
Correa
,
Benjamin
Boitrelle
,
Peter
Goettlicher
,
Manuela
Kuhn
,
Frantisek
Krivan
,
Sabine
Lange
,
Frank
Okrent
,
Igor
Shevyakov
,
Joshua
Supra
,
Maximilian
Tennert
,
Manfred
Zimmer
,
Niccola
Guerrini
,
Ben
Marsh
,
Iain
Sedgwick
,
Giuseppe
Cautero
,
Dario
Giuressi
,
Anastasya
Khromova
,
Ralf
Menk
,
Giovanni
Pinaroli
,
Luigi
Stebel
,
Alan
Greer
,
Tim
Nicholls
,
Ulrik
Pedersen
,
Nicola
Tartoni
,
Hyo Jung
Hyun
,
Kyung Sook
Kim
,
Seung Yu
Rah
,
Heinz
Graafsma
Abstract: In this paper, we are presenting the Percival detector, a monolithic CMOS Imager for detection of soft x-rays in Synchrotron Rings and Free Electron Lasers. The imager consists in a 2D array of many (2M) small (27um pitch) pixels, without dead or blind zones in the imaging area. The imager achieves low noise and high dynamic range by means of an adaptive-gain in-pixel circuitry, that has been validated on prototypes. The imager features on-chip Analogue-to-Digital conversion to 12+1 bits, and has a readout speed which is compatible with most of Free Electron Laser Facilities. For direct detection of low-energy x-rays, the imager is back-illuminated and post-processed to achieve 100% fill factor.
|
Jan 2019
|
|
B18-Core EXAFS
|
Urmimala
Maitra
,
Robert A.
House
,
James W.
Somerville
,
Nuria
Tapia-Ruiz
,
Juan G.
Lozano
,
Niccolo
Guerrini
,
Rong
Hao
,
Kun
Luo
,
Liyu
Jin
,
Miguel A.
Pérez-Osorio
,
Felix
Massel
,
David M.
Pickup
,
Silvia
Ramos
,
Xingye
Lu
,
Daniel E.
Mcnally
,
Alan V.
Chadwick
,
Feliciano
Giustino
,
Thorsten
Schmitt
,
Laurent C.
Duda
,
Matthew R.
Roberts
,
Peter G.
Bruce
Diamond Proposal Number(s):
[12559]
Abstract: The search for improved energy-storage materials has revealed Li- and Na-rich intercalation compounds to have promise as a new class of high-capacity cathodes. They exhibit capacities in excess of what would be expected from alkali-ion removal/reinsertion charge compensated by the transition-metal ions. The additional capacity is provided through charge compensation by oxygen-redox chemistry and some oxygen loss. It has been reported previously that O-redox occurs in O-2p orbitals that interact with alkali-ions in the transition-metal and alkali-ion layers (i.e. O-redox occurs in compounds containing Li+ - O2p - Li+ interactions). Na2/3[Mg0.28Mn0.72]O2 exhibits excess capacity; here we show this is also due to O-redox, despite Mg2+ residing in the transition-metal (TM) layers rather than alkali-metal ions, demonstrating that excess alkali-metal ions are not required to activate O-redox. We also show that unlike the alkali-rich compounds, Na2/3[Mg0.28Mn0.72]O2 does not lose O. Extraction of alkali ions from the alkali and TM layers in the alkali-rich compounds results in severely underbonded oxygen promoting oxygen loss, whereas Mg2+ remains in Na2/3[Mg0.28Mn0.72]O2 stabilising oxygen.
|
Jan 2018
|
|
Detectors
|
J.
Correa
,
A.
Marras
,
C. B.
Wunderer
,
P.
Göttlicher
,
S.
Lange
,
S.
Reza
,
I.
Shevyakov
,
M.
Tennert
,
M.
Niemann
,
H.
Hirsemann
,
S.
Smoljanin
,
J.
Supra
,
Q.
Xia
,
M.
Zimmer
,
A.
Allahgoli
,
A.
Gloskovskii
,
J.
Viefhaus
,
F.
Scholz
,
J.
Seltmann
,
S.
Klumpp
,
G.
Cautero
,
D.
Giuressi
,
A.
Khromova
,
R.
Menk
,
G.
Pinaroli
,
L.
Stebel
,
S.
Rinaldi
,
N.
Zema
,
D.
Catone
,
U.
Pedersen
,
N.
Tartoni
,
N.
Guerrini
,
B.
Marsh
,
I.
Sedgwick
,
T. J.
Nicholls
,
R.
Turchetta
,
H. J.
Hyun
,
K. S.
Kim
,
S. Y.
Rah
,
M. E.
Hoenk
,
A. D.
Jewell
,
T. J.
Jones
,
S.
Nikzad
,
H.
Graafsma
Abstract: The PERCIVAL soft X-ray imager is being developed by DESY, RAL, Elettra, DLS, and PAL to address the challenges at high brilliance Light Sources such as new-generation Synchrotrons and Free Electron Lasers. Typical requirements for detector systems at these sources are high frame rates, large dynamic range, single-photon counting capability with low probability of false positives, high quantum efficiency, and (multi)-mega-pixel arrangements. PERCIVAL is a monolithic active pixel sensor, based on CMOS technology. It is designed for the soft X-ray regime and, therefore, it is post-processed in order to achieve high quantum efficiency in its primary energy range (250 eV to 1 keV) . This work will report on the latest experimental results on charge collection efficiency obtained for multiple back-side-illuminated test sensors during two campaigns, at the P04 beam-line at PETRA III, and the CiPo beam-line at Elettra, spanning most of the primary energy range as well as testing the performance for photon-energies below 250 eV . In addition, XPS surface analysis was used to cross-check the obtained results.
|
Dec 2016
|
|
B18-Core EXAFS
|
Kun
Luo
,
Matthew R.
Roberts
,
Rong
Hao
,
Niccolo
Guerrini
,
David
Pickup
,
Yi-Sheng
Liu
,
Kristina
Edström
,
Jinghua
Guo
,
Alan
Chadwick
,
Laurent C.
Duda
,
Peter
Bruce
Diamond Proposal Number(s):
[12635]
Abstract: During the charging and discharging of lithium-ion-battery cathodes through the de- and reintercalation of lithium ions, electroneutrality is maintained by transition-metal redox chemistry, which limits the charge that can be stored. However, for some transition-metal oxides this limit can be broken and oxygen loss and/or oxygen redox reactions have been proposed to explain the phenomenon. We present operando mass spectrometry of 18O-labelled Li1.2[Ni0.13 2+Co0.13 3+Mn0.54 4+]O2, which demonstrates that oxygen is extracted from the lattice on charging a Li1.2[Ni0.13 2+Co0.13 3+Mn0.54 4+]O2 cathode, although we detected no O2 evolution. Combined soft X-ray absorption spectroscopy, resonant inelastic X-ray scattering spectroscopy, X-ray absorption near edge structure spectroscopy and Raman spectroscopy demonstrates that, in addition to oxygen loss, Li+ removal is charge compensated by the formation of localized electron holes on O atoms coordinated by Mn4+ and Li+ ions, which serve to promote the localization, and not the formation, of true O2 2− (peroxide, O–O ∼1.45 Å) species. The quantity of charge compensated by oxygen removal and by the formation of electron holes on the O atoms is estimated, and for the case described here the latter dominates.
|
Mar 2016
|
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