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Author |
Figueroa, D.G.; Raatikainen, S.; Rasanen, S.; Tomberg, E. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Implications of stochastic effects for primordial black hole production in ultra-slow-roll inflation |
Type |
Journal Article |
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Year |
2022 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
05 |
Issue |
5 |
Pages |
027 - 48pp |
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Keywords ![sorted by Keywords field, descending order (down)](img/sort_desc.gif) |
inflation; primordial black holes; dark matter theory; massive black holes |
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Abstract |
We study the impact of stochastic noise on the generation of primordial black hole (PBH) seeds in ultra-slow-roll (USR) inflation with numerical simulations. We consider the non-linearity of the system by consistently taking into account the noise dependence on the inflaton perturbations, while evolving the perturbations on the coarse-grained background affected by the noise. We capture in this way the non-Markovian nature of the dynamics, and demonstrate that non-Markovian effects are subleading. Using the Delta N formalism, we find the probability distribution P(R) of the comoving curvature perturbation R. We consider inflationary potentials that fit the CMB and lead to PBH dark matter with i) asteroid, ii) solar, or iii) Planck mass, as well as iv) PBHs that form the seeds of supermassive black holes. We find that stochastic effects enhance the PBH abundance by a factor of O(10)-O(10(8)), depending on the PBH mass. We also show that the usual approximation, where stochastic kicks depend only on the Hubble rate, either underestimates or overestimates the abundance by orders of magnitude, depending on the potential. We evaluate the gauge dependence of the results, discuss the quantum-to-classical transition, and highlight open issues of the application of the stochastic formalism to USR inflation. |
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Address |
[Figueroa, Daniel G.] CSIC, Inst Fis Corpuscular IFIC, E-46980 Valencia, Spain, Email: daniel.figueoa@ific.uv.es; |
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Publisher |
IOP Publishing Ltd |
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English |
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ISSN |
1475-7516 |
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Expedition |
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Conference |
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Notes |
WOS:000804493000010 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5239 |
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Permanent link to this record |
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Author |
Fernandez-Tejero, J. et al; Soldevila, U. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Humidity sensitivity of large area silicon sensors: Study and implications |
Type |
Journal Article |
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Year |
2020 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
978 |
Issue |
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Pages |
164406 - 6pp |
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Keywords ![sorted by Keywords field, descending order (down)](img/sort_desc.gif) |
Humidity sensitivity; Large area silicon sensors; Slim-edge; HL-LHC |
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Abstract |
The production of large area sensors is one of the main challenges that the ATLAS collaboration faces for the new Inner-Tracker full-silicon detector. During the prototype fabrication phase for the High Luminosity Large Hadron Collider upgrade, several ATLAS institutes observed indications of humidity sensitivity of large area sensors, even at relative humidities well below the dew point. Specifically, prototype Barrel and End-Cap silicon strip sensors fabricated in 6-inch wafers manifest a prompt decrease of the breakdown voltage when operating under high relative humidity, adversely affecting the performance of the sensors. In addition to the investigation of these prototype sensors, a specific fabrication batch with special passivation is also studied, allowing for a deeper understanding of the responsible mechanisms. This work presents an extensive study of this behaviour on large area sensors. The locations of the hotspots at the breakdown voltage at high humidity are revealed using different infrared thermography techniques. Several palliative treatments are attempted, proving the influence of sensor cleaning methods, as well as baking, on the device performance, but no improvement on the humidity sensitivity was achieved. Furthermore, a study of the incidence of the sensitivity in different batches is also presented, introducing a hypothesis of the origins of the humidity sensitivity associated to the sensor edge design, together with passivation thickness and conformity. Several actions to be taken during sensor production and assembly are extracted from this study, in order to minimize the impact of humidity sensitivity on the performance of large area silicon sensors for High Energy Physics experiments. |
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Address |
[Fernandez-Tejero, J.; Avino, O.; Fleta, C.; Ullan, M.; Vellvehi, M.] CSIC, Ctr Nacl Microelect IMB CNM, Campus UAB Bellaterra, Barcelona 08193, Spain, Email: Xavi.Fdez@cern.ch |
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Elsevier |
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English |
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ISSN |
0168-9002 |
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Expedition |
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Conference |
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Notes |
WOS:000560076700009 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4504 |
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Permanent link to this record |
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Author |
Di Valentino, E.; Melchiorri, A.; Mena, O.; Vagnozzi, S. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Interacting dark energy in the early 2020s: A promising solution to the H-0 and cosmic shear tensions |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physics of the Dark Universe |
Abbreviated Journal |
Phys. Dark Universe |
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Volume |
30 |
Issue |
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Pages |
100666 - 12pp |
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Keywords ![sorted by Keywords field, descending order (down)](img/sort_desc.gif) |
Hubble tension; Cosmological parameters; Dark matter; Dark energy; Interacting dark energy |
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Abstract |
We examine interactions between dark matter and dark energy in light of the latest cosmological observations, focusing on a specific model with coupling proportional to the dark energy density. Our data includes Cosmic Microwave Background (CMB) measurements from the Planck 2018 legacy data release, late-time measurements of the expansion history from Baryon Acoustic Oscillations (BAO) and Supernovae Type Ia (SNeIa), galaxy clustering and cosmic shear measurements from the Dark Energy Survey Year 1 results, and the 2019 local distance ladder measurement of the Hubble constant H-0 from the Hubble Space Telescope. Considering Planck data both in combination with BAO or SNeIa data reduces the H-0 tension to a level which could possibly be compatible with a statistical fluctuation. The very same model also significantly reduces the Omega(m) – sigma(8) tension between CMB and cosmic shear measurements. Interactions between the dark sectors of our Universe remain therefore a promising joint solution to these persisting cosmological tensions. |
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Address |
[Di Valentino, Eleonora] Univ Manchester, Jodrell Bank, Ctr Astrophys, Manchester M13 9PL, Lancs, England, Email: eleonora.divalentino@manchester.ac.uk; |
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Elsevier |
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English |
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ISSN |
2212-6864 |
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Conference |
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Notes |
WOS:000595300400037 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4646 |
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Permanent link to this record |
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Author |
Miyagawa, P.S. et al; Bernabeu, P.; Lacasta, C.; Solaz, C.; Soldevila, U. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Analysis of the results from Quality Control tests performed on ATLAS18 Strip Sensors during on-going production |
Type |
Journal Article |
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Year |
2024 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
1064 |
Issue |
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Pages |
169457 - 9pp |
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Keywords ![sorted by Keywords field, descending order (down)](img/sort_desc.gif) |
HL-LHC; ATLAS; ITk; Strip sensors |
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Abstract |
The ATLAS experiment will replace its existing Inner Detector with the new all -silicon Inner Tracker (ITk) to cope with the operating conditions of the forthcoming high -luminosity phase of the LHC (HL-LHC). The outer regions of the ITk will be instrumented with similar to 18000 ATLAS18 strip sensors fabricated by Hamamatsu Photonics K.K. (HPK). With the launch of full-scale sensor production in 2021, the ITk strip sensor community has undertaken quality control (QC) testing of these sensors to ensure compliance with mechanical and electrical specifications agreed with HPK. The testing is conducted at seven QC sites on each of the monthly deliveries of similar to 500 sensors. This contribution will give an overview of the QC procedures and analysis; the tests most likely to determine pass/fail for a sensor are IV, long-term leakage current stability, full strip test and visual inspection. The contribution will then present trends in the results and properties following completion of similar to 60% of production testing. It will also mention challenges overcome through collaborative efforts with HPK during the early phases of production. With less than 5% of sensors rejected by QC testing, the overall production quality has been very good. |
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Address |
[Miyagawa, P. S.; Beck, G. A.; Bevan, A. J.; Chen, Z.; Dawson, I.; Zenz, S. C.] Queen Mary Univ London, Particle Phys Res Ctr, GO Jones Bldg, Mile End Rd, London E14NS, England, Email: paul.miyagawa@cern.ch |
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Publisher |
Elsevier |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0168-9002 |
ISBN |
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Expedition |
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Conference |
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Notes |
WOS:001249611300001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
6158 |
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Permanent link to this record |
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Author |
Latonova, V. et al; Bernabeu, J.; Lacasta, C.; Solaz, C.; Soldevila, U. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
Characterization of the polysilicon resistor in silicon strip sensors for ATLAS inner tracker as a function of temperature, pre- and post-irradiation |
Type |
Journal Article |
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Year |
2023 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
1050 |
Issue |
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Pages |
168119 - 5pp |
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Keywords ![sorted by Keywords field, descending order (down)](img/sort_desc.gif) |
HL-LHC; ATLAS ITk; Silicon micro-strip sensor; Polysilicon bias resistor; Testchip |
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Abstract |
The high luminosity upgrade of the Large Hadron Collider, foreseen for 2029, requires the replacement of the ATLAS Inner Detector with a new all-silicon Inner Tracker (ITk). The expected ultimate total integrated luminosity of 4000 fb(-1) means that the strip part of the ITk detector will be exposed to the total particle fluences and ionizing doses reaching the values of 1.6 center dot 10(15) MeVn(eq)/cm(2) and 0.66MGy, respectively, including a safety factor of 1.5. Radiation hard n(+)-in-p micro-strip sensors were developed by the ATLAS ITk strip collaboration and are produced by Hamamatsu Photonics K.K. The active area of each ITk strip sensor is delimited by the n-implant bias ring, which is connected to each individual n(+) implant strip by a polysilicon bias resistor. The total resistance of the polysilicon bias resistor should be within a specified range to keep all the strips at the same potential, prevent the signal discharge through the grounded bias ring and avoid the readout noise increase. While the polysilicon is a ubiquitous semiconductor material, the fluence and temperature dependence of its resistance is not easily predictable, especially for the tracking detector with the operational temperature significantly below the values typical for commercial microelectronics. Dependence of the resistance of polysilicon bias resistor on the temperature, as well as on the total delivered fluence and ionizing dose, was studied on the specially-designed test structures called ATLAS Testchips, both before and after their irradiation by protons, neutrons, and gammas to the maximal expected fluence and ionizing dose. The resistance has an atypical negative temperature dependence. It is different from silicon, which shows that the grain boundary has a significant contribution to the resistance. We discuss the contributions by parameterizing the activation energy of the polysilicon resistance as a function of the temperature for unirradiated and irradiated ATLAS Testchips. |
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Address |
[Latonova, V.; Federicova, P.; Kroll, J.; Kvasnicka, J.; Mikestikova, M.] Acad Sci Czech Republ, Inst Phys, Slovance 2, Prague 8, Czech Republic, Email: vera.latonova@cern.ch |
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Publisher |
Elsevier |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0168-9002 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001035405300001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5601 |
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Permanent link to this record |