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Jorge Molina

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Papers by Jorge Molina

Measurement of radioactive contamination in the high-resistivity silicon CCDs of the DAMIC experiment

Journal of Instrumentation, 2015

We present measurements of radioactive contamination in the high-resistivity silicon charge-coupl... more We present measurements of radioactive contamination in the high-resistivity silicon charge-coupled devices (CCDs) used by the DAMIC experiment to search for dark matter particles. Novel analysis methods, which exploit the unique spatial resolution of CCDs, were developed to identify α and β particles. Uranium and thorium contamination in the CCD bulk was measured through α spectroscopy, with an upper limit on the 238 U (232 Th) decay rate of 5 (15) kg −1 d −1 at 95% CL. We also searched for pairs of spatially correlated electron tracks separated in time by up to tens of days, as expected from 32 Si-32 P or 210 Pb-210 Bi sequences of β decays. The decay rate of 32 Si was found to be 80 +110 −65 kg −1 d −1 (95% CI). An upper limit of ∼35 kg −1 d −1 (95% CL) on the 210 Pb decay rate was obtained independently by α spectroscopy and the β decay sequence search. These levels of radioactive contamination are sufficiently low for the successful operation of CCDs in the forthcoming 100 g DAMIC detector.

Neutrino interaction classification with a convolutional neural network in the DUNE far detector

Physical Review D, 2020

A solution for future single-electron-counting fast-readout Skipper-CCD experiments: high channel density front-end electronics design and noise performance analysis

The Skipper-CCDs, a special type of charge-coupled device (CCD) sensor that features sub-electron... more The Skipper-CCDs, a special type of charge-coupled device (CCD) sensor that features sub-electron readout noise levels, was proposed decades ago. However, only in recent years it has been possible to develop large size Skipper-CCDs ensuring stable operation. Their extreme low noise operation makes them suitable for experiments that require low thresholds and high energy resolution, such as dark matter and neutrino interactions detection, and more recently quantum-imaging and astronomy. New experiments are planning to use kilograms of active silicon from Skipper-CCDs as sensitive mass. In this way, they can achieve extremely low detection thresholds and a high probability of particle interaction. However, this approach needs arrays of thousands of Skipper- CCDs operating at the same time imposing challenging requirements. Also, introduction of this technology in astronomy and quantum-imaging applications requires a large number of channels per sensor to speed up the readout. The fron...

$Research paper thumbnail of Measurement of the ratio $\mathcal{B}( B_s^0\rightarrow J/\psi f_0(980))/\mathcal{B}(B_s^0\rightarrow J/\psi\phi(1020))$ in pp collisions at $\sqrt{s} = 7~$TeV$

Measurement of the ratio $\mathcal{B}( B_s^0\rightarrow J/\psi f_0(980))/\mathcal{B}(B_s^0\rightarrow J/\psi\phi(1020))$ in pp collisions at $\sqrt{s} = 7~$TeV

The fatty acid composition of the muscle tissue of Wallagu attu found in Gangetic West Bengal, In... more The fatty acid composition of the muscle tissue of Wallagu attu found in Gangetic West Bengal, India was investigated to get an insight of its nutritional capacity. The fish muscle proved to be a rich source of both mono and poly unsaturated fatty acids. Of the saturated fatty acids Palmitic and Heneicosanoic acid is detected in considerable amount. Of the MUFA's present Palmetoleic acid, Elaidic acid, Oleic acid and nervonic acid is found in good amount. Nutritionally important ù-6 PUFA's like Linoleic acid and Arachidonic acid are found in the fish. EPA and DHA the two star ù-3 PUFA's whose health benefits are beyond doubt are also detected in the fish. Wallagu attu is generally not farmed as it devours other fishes but considering its nutritional capacity and high market demands, its farming may prove beneficial for consumers and producers.

Software-based Integrating Charge-Coupled Devices Signal Processing Using Correlated Double Sampling Technique

This paper discusses a method for reconstructing an image from the digitized output signal of an ... more This paper discusses a method for reconstructing an image from the digitized output signal of an integrating chargecoupled devices camera (slow scan) based on software by using correlated double sampling and efficient processing resources use for short processing times. The developed software is entirely written in C++ for high speed execution and can work with data acquired by different kind of detection devices with small changes. This work allows to implement a low cost acquiring system for charge coupled devices or provide a development tool suitable to test digital filters, different techniques for pixel computation, or charge-coupled devices signal analysis. Some images produced with real data are shown.

Exploring low-energy neutrino physics with the Coherent Neutrino Nucleus Interaction Experiment

Physical Review D, 2019

The Coherent Neutrino-Nucleus Interaction Experiment (CONNIE) uses low-noise fully depleted charg... more The Coherent Neutrino-Nucleus Interaction Experiment (CONNIE) uses low-noise fully depleted charge-coupled devices (CCDs) with the goal of measuring low-energy recoils from coherent elastic scattering (CEνNS) of reactor antineutrinos with silicon nuclei and testing nonstandard neutrino interactions (NSI). We report here the first results of the detector array deployed in 2016, considering an active mass 47.6 g (8 CCDs), which is operating at a distance of 30 m from the core of the Angra 2 nuclear reactor, with a thermal power of 3.8 GW. A search for neutrino events is performed by comparing data collected with reactor on (2.1 kg-day) and reactor off (1.6 kg-day). The results show no excess in the reactor-on data, reaching the world record sensitivity down to recoil energies of about 1 keV (0.1 keV electron-equivalent). A 95% confidence level limit for new physics is established at an event rate of 40 times the one expected from the standard model at this energy scale. The results presented here provide a new window to low-energy neutrino physics, allowing one to explore for the first time the energies accessible through the low threshold of CCDs. They will lead to new constrains on NSI from the CEνNS of antineutrinos from nuclear reactors.

Volume I. Introduction to DUNE

Journal of Instrumentation, 2020

Three-dimensional projection scintillator tracker spectrometer A.7 Meeting the near detector requ... more Three-dimensional projection scintillator tracker spectrometer A.7 Meeting the near detector requirements A.7.1 Overarching requirements A.7.2 Event rate and flux measurements A.7.3 Control of systematic errors B ND hall and construction C Computing roles and collaborative projects C.1 Roles C.2 Specific collaborative computing projects C.2.1 LArSoft for event reconstruction C.2.2 WLCG/OSG and the HEP Software Foundation C.2.3 Evaluations of other important infrastructure Acknowledgments Glossary Bibliography The DUNE collaboration -iv --iv --iv -List of Figures List of Figures List of Figures A.3 ArgonCube 2×2 demonstrator A.4 Cutaway drawing of an ArgonCube 2×2 demonstrator module A.5 A prototype ArgonCube light readout paddle and a mounted ArCLight paddle A.6 Influence of the LArTPC size on hadron containment A.7 The current ArgonCube dimensions for the DUNE ND A.8 All neutrino events in the nominal 25 t ArgonCube fiducial volume A.9 Events where the visible hadronic system is contained in ArgonCube fiducial volume130 A.10 Muon acceptance as a function of true neutrino energy and true muon energy A.11 Neutrino acceptance as a function of energy and momentum transfer A.12 Neutrino acceptance in the (q 3 , q 0 ) plane as a function of neutrino energy A.13 A beam spill in the LAr component of the DUNE ND A.14 Temporal distribution of ν vertices within a beam spill in the ND LAr component A.15 FHC flux covariance matrices for nominal 35 t ArgonCube A.16 Rate+shape and shape-only bin-by-bin flux uncertainties A.17 Reconstructed ν energy spectra for CC ν µ interactions with charged pions A.18 Momentum spectra of protons ejected from ν interactions in Ar A.19 The ALICE TPC A.20 The ALICE MWPC-based ROC with pad plane readout A.21 Pressure vessel preliminary design A.22 MPD ECAL conceptual design A.23 Conceptual layout of the MPD ECAL A.24 Helmholz coil arrangement A.25 Field map of the superconducting magnet along the z axis A.26 Track-reconstructed ν e CC event in the HPgTPC A.27 Efficiency of track finding in the HPgTPC A.28 Tracking efficiency for protons in the HPgTPC A.29 ALICE and PEP-4 dE/dx-based particle identification as a function of momentum A.30 The TPC stand-alone p T resolution in ALICE for p-Pb collisions A.31 Momentum and angular resolutions for muons in GArSoft A.32 Machine learning residuals for protons in the MPD A.33 Energy and angular resolutions for photons in the MPD ECAL A.34 Oscillation fits to nominal and fake data sets for DUNE-PRISM fake data study A.35 Reconstructed energy distributions for nominal and fake data sets; on-and off-axis A.36 Linear combinations of off-axis fluxes giving FD oscillated spectra; range of parameters A.37 The MINOS near detector event spectrum shown in run periods A.38 Rate vs spectral monitoring of ν beam for 1 σ shifts of the horn positions A.39 A few plastic scintillator cubes assembled with WLS fibers. A.40 The SAND detector configuration A.41 Charge and time spectra for a single 3DST cube A.42 Event displays from the 2018 test beam A.43 SAND beam monitoring capability. A.44 Sample antineutrino interaction in the 3DST -vii --vii --vii -A.45 Reconstructed neutron energy residual in the 3DST A.46 Time between ν interaction vertex in 3DST and earliest neutron-induced hit A.47 Purity of neutron-induced hit in the (time, lever arm) space for the 3DST A.48 Energy resolution for neutron candidates in the (time, lever arm) space for the 3DST B.1 DUNE ND hall from above and side (transverse to beam) -viii --viii --viii -4An "arapuca" is a South American bird trap; the name is used here as an analogy to the way the devices trap photons. These devices have been developed by DUNE collaborators in Brazil.

Results of the engineering run of the Coherent Neutrino Nucleus Interaction Experiment (CONNIE)

Journal of Instrumentation, 2016

$Research paper thumbnail of Search for the production of dark matter in association with top-quark pairs in the single-lepton final state in proton-proton collisions at s = 8 $$ \sqrt{s}=8 $$ TeV$

Search for the production of dark matter in association with top-quark pairs in the single-lepton final state in proton-proton collisions at s = 8 $$ \sqrt{s}=8 $$ TeV

Journal of High Energy Physics, 2015

We investigate the relation between 3d N = 2 theories and 2d free field correlators or Dotsenko-F... more We investigate the relation between 3d N = 2 theories and 2d free field correlators or Dotsenko-Fateev (DF) integrals for Liouville CFT. We show that the S 2 × S 1 partition functions of some known 3d Seiberg-like dualities reduce, in a suitable 2d limit, to known basic duality identities for DF correlators. These identities are applied in a variety of contexts in CFT, as for example in the derivation of the DOZZ 3-point function. Reversing the logic, we can try to guess new 3d IR dualities which reduce to more intricate duality relations for the DF correlators. For example, we show that a recently proposed duality relating the U(N) theory with one flavor and one adjoint to a WZ model can be regarded as the 3d ancestor of the evaluation formula for the DF integral representation of the 3-point correlator. We are also able to interpret the analytic continuation in the number of screening charges, which is performed on the CFT side to reconstruct the DOZZ 3-point function, as the geometric transition relating the 3d U(N) theory to the 5d T 2 theory.

Time reconstruction and performance of the CMS electromagnetic calorimeter

Journal of Instrumentation, 2010

The resolution and the linearity of time measurements made with the CMS electromagnetic calorimet... more The resolution and the linearity of time measurements made with the CMS electromagnetic calorimeter are studied with samples of data from test beam electrons, cosmic rays, and beam-produced muons. The resulting time resolution measured by lead tungstate crystals is better than 100 ps for energy deposits larger than 10 GeV. Crystal-to-crystal synchronization with a precision of 500 ps is performed using muons produced with the first LHC beams in 2008.

Performance of the CMS cathode strip chambers with cosmic rays

Journal of Instrumentation, 2010

Performance of the CMS cathode strip chambers with cosmic rays CMS Collaboration ABSTRACT: The Ca... more Performance of the CMS cathode strip chambers with cosmic rays CMS Collaboration ABSTRACT: The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 µm to 243 µm. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns.

Commissioning of the CMS High-Level Trigger with cosmic rays

Journal of Instrumentation, 2010

The CMS High-Level Trigger (HLT) is responsible for ensuring that data samples with potentially i... more The CMS High-Level Trigger (HLT) is responsible for ensuring that data samples with potentially interesting events are recorded with high efficiency and good quality. This paper gives an overview of the HLT and focuses on its commissioning using cosmic rays. The selection of triggers that were deployed is presented and the online grouping of triggered events into streams and primary datasets is discussed. Tools for online and offline data quality monitoring for the HLT are described, and the operational performance of the muon HLT algorithms is reviewed. The average time taken for the HLT selection and its dependence on detector and operating conditions are presented. The HLT performed reliably and helped provide a large dataset. This dataset has proven to be invaluable for understanding the performance of the trigger and the CMS experiment as a whole.

Charge coupled devices for detection of coherent neutrino-nucleus scattering

Physical Review D, 2015

This article details the potential for using Charge Coupled Devices (CCD) to detect low-energy ne... more This article details the potential for using Charge Coupled Devices (CCD) to detect low-energy neutrinos through their coherent scattering with nuclei. The detection of neutrinos through this standard model process has not been accessible because of the small energy deposited in such interactions with the detector nuclei. Typical particle detectors have thresholds of a few keV, and most of the energy deposition expected from coherent scattering is well below this level. The devices we discuss can be operated at a threshold of approximately 30 eV, making them ideal for observing this signal. For example, the number of coherent scattering events expected on a 52 gram CCD array located next to a power nuclear reactor is estimated to be near to 626 events/year. The results of our study show that detection at a confidence level of 99% can be reached within three months for this kind of detector array.

Plasma effect in silicon charge coupled devices (CCDs)

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2011

The CONNIE experiment

Journal of Physics: Conference Series, 2016

The CONNIE experiment uses fully depleted, high resistivity CCDs as particle detectors in an atte... more The CONNIE experiment uses fully depleted, high resistivity CCDs as particle detectors in an attempt to measure for the first time the Coherent Neutrino-Nucleus Elastic Scattering of antineutrinos from a nuclear reactor with silicon nuclei. This talk, given at the XV Mexican Workshop on Particles and Fields (MWPF), discussed the potential of CONNIE to perform this measurement, the installation progress at the Angra dos Reis nuclear power plant, as well as the plans for future upgrades.

Description of the data obtained with the CCD detectors of the Coherent Neutrino Nucleus Interaction Experiment (CONNIE)

2019 IEEE CHILEAN Conference on Electrical, Electronics Engineering, Information and Communication Technologies (CHILECON), 2019

This paper reproduces the energy spectrum measured by the CCD (Charge-Coupled Devices) detectors ... more This paper reproduces the energy spectrum measured by the CCD (Charge-Coupled Devices) detectors of the CONNIE experiment that looks for the Coherent Elastic Scattering process between Antineutrinos coming from a nuclear reactor and silicon nuclei. The background registered by the CCDs were studied with the GEANT4 toolkit, through the simulation of atmospheric muons and beta particles coming out from the lead used to shield the detectors. The amount of both contributions were estimated from data, with the result that the contribution of Beta particles is negligible in this case.

DAMIC: a novel dark matter experiment

DAMIC (Dark Matter in CCDs) is a novel dark matter experiment that has unique sensitivity to dark... more DAMIC (Dark Matter in CCDs) is a novel dark matter experiment that has unique sensitivity to dark matter particles with masses below 10 GeV. Due to its low electronic readout noise (R.M.S. ~3 e-) this instrument is able to reach a detection threshold below 0.5 keV nuclear recoil energy, making the search for dark matter particles with low masses possible. We report on early results and experience gained from a detector that has been running at SNOLAB from Dec 2012. We also discuss the measured and expected backgrounds and present the plan for future detectors to be installed in 2014.

Volume IV. The DUNE far detector single-phase technology

Journal of Instrumentation

The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae... more The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. DUNE is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. Central to achieving DUNE's physics program is a far detector that combines the many tens-of-kiloton fiducial mass necessary for rare event searches with sub-centimeter spatial resolution in its ability to image those events, allowing identification of the physics signatures among the numerous backgrounds. In the single-phase liquid argon time-projection chamber (LArTPC) technology, ionization charges drift horizontally in the liquid argon under the influence of an electric field towards a vertical anode, where they are read out with fine granularity. A photon detection system supplements the TPC, directly enhancing physics capabilities for all three DUNE physics drivers and opening up prospects for further physics explorations. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume IV presents an overview of the basic operating principles of a single-phase LArTPC, followed by a description of the DUNE implementation. Each of the subsystems is described in detail, connecting the high-level design requirements and decisions to the overriding physics goals of DUNE.

Search for light mediators in the low-energy data of the CONNIE reactor neutrino experiment

Journal of High Energy Physics, Apr 1, 2020

The CONNIE experiment is located at a distance of 30 m from the core of a commercial nuclear reac... more The CONNIE experiment is located at a distance of 30 m from the core of a commercial nuclear reactor, and has collected a 3.7 kg-day exposure using a CCD detector array sensitive to an ∼1 keV threshold for the study of coherent neutrino-nucleus elastic scattering. Here we demonstrate the potential of this low-energy neutrino experiment as a probe for physics Beyond the Standard Model, by using the recently published results to constrain two simplified extensions of the Standard Model with light mediators. We compare the new limits with those obtained for the same models using neutrinos from the Spallation Neutron Source. Our new constraints represent the best limits for these simplified models among the experiments searching for CEνNS for a light vector mediator with mass M Z < 10 MeV, and for a light scalar mediator with mass M φ < 30 MeV. These results constitute the first use of the CONNIE data as a probe for physics Beyond the Standard Model.

Flame imaging reconstruction method using high resolution spectral data of OH *, CH * and C 2 * radicals

International Journal of Thermal Sciences