Author: Marian ZAMFIRESCU
Abstract: Workshopul CETAL are rolul de a stimula la nivelul Institutului comunicarea stiintifica intre laboratoare, discutiile stiintifice informale, dar de calitate, activitatile de gen brainstorming, deschiderea, colegialitatea, initiativa tinerilor. Si nu in ultimul rand, este o ocazie de popularizare a infrastructurii CETAL in randul colegilor din INFLPR.
Author: Ion N. MIHĂILESCU
Author: Diana CHIOIBAȘU
Abstract: Protezele din Ti6Al4V au fost imprimate 3D prin depunerea directa cu laserul. Pentru imprimare a fost utilizat un braț robotic cu ajutorul caruia s-au executat miscarile duzei care livreaza pulberea și fasciculul laser. Forma protezei a fost proiectata in software-ul grafic SolidWorks (Dassault Systems) si apoi importata in TruTops Cell (Trumpf, Germania), un program generator de coduri pentru miscarile robotului. Dispozitivele medicale implantabile se numara printre cele mai compatibile cu imprimarea 3D datorita nevoii de personalizare a formei și dimensiunii, in functie de aspectul fracturii.
Author: Liviu DUȚĂ
The Earth's nowadays available mineral resources are threatened to run short due to the world demographic increase and rapid economic growth, and therefore, the search of alternatives is feasible. Calcium phosphate coatings for metallic implants are the subject of the recent researches in the attempt to improve their biointegration. The mineral constituent of vertebrate skeletal systems mainly consists of calcium-deficient hydroxyapatite (HA) doped with various ions. Pure HA, with chemical formula Ca10(PO4)6(OH)2, is one of the most well-known and studied biocompatible materials, used as implantable ceramic due to its chemical and structural similarity with human hard tissues (50% mass, 70% volume). In the field of bioactive materials, the final milestone is to reach the biomimetism, i.e. the implant to possess traits so similar to the human bone, which it can perfectly integrate as part of it, without causing adverse reactions. This goal cannot be attained using pure HA synthesized by classical chemical routes (i.e. sol-gel or precipitation), which involve rather laborious, polluting and time-consuming methods and can be considered quite expensive. It should contain oligoelements, which are present in a living bone and eventually dopants that can boost its bioactivity. Hence, the simplest way to obtain an apatite with composition similar to that of a healthy bone, would be to manufacture it from actual biological renewable resources ("waste products") (i.e., cortical or cancellous animal-origin bones resulted from general consumption, sea shells, fish bones). This way,
the production of much cheaper medical devices can be enabled. In this context, we report on the synthesis by Pulsed Laser Deposition of simple and doped hydroxyapatite thin films of biological origin. Detailed physical, chemical, mechanical and biological investigations were performed. Taking into consideration their enhanced characteristics, corroborated with a low fabrication cost generated by renewable resources, one should consider these biological-derived materials as promising prospective alternatives to synthetic HA for the fabrication of a next generation of coated implants with rapid osteointegration. Acknowledgements: part of this work was supported by a grant of Ministry of Research and Innovation, CNCS - UEFISCDI, project number PN-III-P1-1.1-PD-2016-1568 (PD 6/2018), within PNCDI III and Core Programme - Contract 3N/2018.
Author: Marian ZAMFIRESCU
CETAL-PW laser system have been comissioned in 2014, in the frame of CETAL project (2010-2014). The research activity of the CETAL-PW laboratory is focused on the interaction of ultra-short high-intensity lasers with matter and its aplications: plasma physics and diagnostics, production of sources of energetic particles and radiation and their applications in different scientific fields (medicine, chemistry, space science). When the femtosecond laser pulse is tightly focused, intensities up to 1019-1020 W/cm2 can be achieved at the target. The current status of CETAL-PW laser infrastructure and current research activities will be presented.
Author: Mihai ȘERBĂNESCU
Abstract: The CETAL-INFLPR laser facility (http://cetal.inflpr.ro/pw) aims to runs at 45 TW with 10 Hz repetition rate and at 1 PW with repetition rate of 0.1 Hz, delivering pulses with about 25 fs pulse durations with beam size of 200 mm full aperture and 160 mm FWHM. Both of those working regimes, are delivering pulses into the interaction chamber placed inside radiation shielding underground bunker. A customized synchronization system was implemented for the laser system in order to measure the puls duration and temporal shape and to extend the delay generation unit capabilities over shot to shot or burst modes for delivering pulses and synchronize signals to experimental area. The present paper describes detailed the entire solution of synchronization system.
Author: Alexandru ACHIM
Abstract: Laser beam directionality tracking, alignment and front quality are essential problems in laser-matter interaction experiment and are key elements from accurate results. A quantitative measurement of laser-beam wave front modification can be performed by analyzing the intensity profile recorded with a CCD camera placed at the far-field of the beam. CCD should have the the smallest available pixel size that would provide the best spatial resolution in order to record the intensity profile features of the focused beam. The far-filed intensity profiles shape and contrast is directly correlated with the laser beam wave front structure modification at the input of the focusing element. Several specific functions (centroid detection, pixel values histogram ) are applied to a captured frame for obtaining relevant information on spot position, area of the spot, background level, spatial contrast (SNR), Strehl factor (fraction of intensity in a circle that include the spot at 1/e*I relative to full picture total pixel value ) and so on. Image processing is performed using build-in function from opensource software packages as Python but also proprietary software like Mathematica and Matlab.
Author: Andreea GROZA
The proton acceleration at energies up to tens of MeV by high intensity laser pulses (I>1018 W/cm2) interaction with thin solid targets, are of interest from experimentally and theoretically point of view. The analysis of protons beam densities and their energy distribution are usually performed with radiochromic films or nuclear track detectors. In this communication, we propose a method for analysis of the tracks left by laser - accelerated proton beams in solid nuclear track detectors of CR-39 type for the estimation of proton energies ranging between 1-15 MeV. For such purpose, we designed an unique experimental set-up that connect in a compact manner the target holder with the detector holder, and the laser spot optical analysis system. The CR-39 detectors was calibrated by irradiation with monoenergetic proton beams of various energies for the finding of the relation between the proton track diameter as function of proton incident energy. A comparison between these experimental data and the results obtained by numerical calculations has been performed. Thus, we established a calibration curve that link the proton track diameter with proton incident energy on the detector. The laser driven proton tracks in CR-39 detectors has been revealed by atomic force microscopy. The diameters of proton tracks measured by atomic force microscopy are energetically characterized using an analytical equation derived from the calibration curve.
Author: Consuela MATEI
Abstract: Real-time physical and dosimetric characterization of laser accelerated particle beams is still challenged by the supply of stable and reliable particle beams, as well by their features as high pulse dose, broad energy spectrum and short pulse duration. From a very long history in measuring doses in charged particle beams, it has been proved that the ion chambers represent the gold standard in such dose measurements, but the calculus of the correct dose from the measured charge requires a series of corrections that can seriously limit the method. In the frame of the project ELIDOSE (20-ELI/2016 „Development of a Novel 2D Detector Array for Dosimetric Characterisation of ELI Laser Accelerated Charged Particle Beams”) we try to improve this aspect by proposing an array detector that would allow the simultaneous measurement of the recombination and polarity corrections, and of the dose. The detector will be build from 4 Advanced Markus ion chambers, mounted together in a PMMA frame. Previously, the response to various charged particle beams and reciprocal influences between active areas were studied through the FLUKA modelling. In order to validate our simulations, the results were compared with initial measurements performed in known beams: 6 to 15 MeV electron beams generated by a Siemens radiotherapy LINAC(Clinical Hospital "COLTEA") and 3 MeV and 18 MeV proton beams at the Tandetron and TR19 Cyclotron accelerators of the IFIN-HH. Moreover, the beam geometry of the proton beams was initially recorded by EBT2 radiochromic films which were subsequently read with an Epson Expression 11000XL scanner and then analysed with Mephisto mcc. Further, new sessions of measurements will be done in 2-detector and 4-detector configuration, and after the correlation of the results with the FLUKA simulations, the new outcome will help to improve the design of the array detector.
Author: Dan STUTMAN
Helical-phase or "vortex" light beams have theunique property of carrying orbital angular momentum (OAM) of m? per photon, with 'm' an integer. The photon OAM can be used to apply torque to matter, or to excite quantum transitions forbidden by the selection rules. A four year research program has beed proposed at ELI-NP and CETAL laser facilities in Romania, aimed at exploring new frontiers of light-matter interaction using helical photon beams with extreme intensity and extreme energy. The program includes: (i) producing extreme intensity helical laser beams and using them to study the interaction between relativistic intensity OAM light and dense plasmas, and (ii) producing helical beams at gamma-ray energies and using them to study the fundamental interactions of OAM carrying gamma-rays with electrons and nuclei. Extreme light intensities will be achieved using the PW lasers at CETAL and ELI-NP and extreme photon energies using the Gamma Beam System also at ELI-NP. The experimental research will be accompanied by fundamental theoretical research.
Author: Radu IONICIOIU
Author: Bogdan MIHALCEA
Un numar considerabil de grupuri de cercetare din tari europene care sunt membre ESA, sunt implicate in studii privind dezvoltarea si implementarea de noi tehnologii cuantice. Cu toate acestea, aplicatiile spatiale ale senzorilor cuantici cu atomi ultra-reci sunt inca in stadiu incipient. Rezultate de ultima ora deschid perspective extrem de promitatoare pentru adaptarea acestor tehnologii si utilizarea lor in spatiu. Inititiva C-COOL are ca obiect infiintarea unei retele de facilitati care sa permita integrarea, testarea si optimizarea senzorilor cuantici, la nivel de sistem, sub-sistem sau componenta individuala, pentru a matura aceste tehnologii la scara nationala si europeana. Aceste tipuri de instrumente extrem de sensibile bazate pe atomi ultra-reci, sunt destinate efectuarii unor experimente fundamentale pentru stiinta si pentru observarea Pamantului. In particular, senzorii metrologici bazati pe proprietatile acestor atomi deschid calea spre progrese remarcabile pentru noile misiuni spatiale. Va fi prezentata structura consortiului care se construieste in prezent, in care INFLPR este membru. Se va insista asupra sinergiei dintre initiativa C-COOL si programele stiintifice nationale si internationale, in prezent si in viitor.
Author: Cătălin TICOȘ
We demonstrate transport of charged microscopic matter by a 13 keV collimated electron beam (EB) over tens of millimetres in a dusty plasma. Hundreds of electrically charged microspheres levitated inside a weakly ionized plasma and forming a plasma crystal are locally irradiated. When the EB is turned on a dust flow moving with a peak speed ~10 mm/s in the direction of the EB is produced. Far from the irradiation zone the plasma crystal preserves its spatial structure. The peak kinetic energy of the dust flow is ~630 eV resulting in an energy transfer factor of 0.048 from the EB to the microparticles. The flow is laminar in the first 300 ms and becomes turbulent as its speed and width increase. During this transition vortices formed initially at the entrance of the EB in the plasma crystal give rise to subsequent eddies which propagate downstream the flow. The particle image velocimetry (PIV) technique is employed to monitor the evolution of the dust flow in time. Spatio-temporal maps of the dust flow speed, kinetic energy and vorticity give insights into the flow dynamic regime.
Author: Cristina SURDU-BOB
A new optical imaging facility of our lab, based on diffraction phase microscopy (DPM) is presented. The system combines two types of optical information from a material: the amplitude of the imaging field and the phase to obtain quantitative topographical and refractive index data [(Patent number: 20090290156, Popescu, G., Quantitative Phase Imaging of Cells and Tissues. 2011, New York: McGraw-Hill.]. DPM does not only reach the capabilities of an atomic force microscope (AFM) by being able to map surfaces and give film thickness and roughness information but also outperforms the AFM by going down to the sub-nanometric level. Moreover, DPM provides real-time images of the surface, thus allowing for processes monitoring - performance not encountered in AFM [Edwards, C., et al., Diffraction phase microscopy: monitoring nanoscale dynamics in materials science [invited]. Appl Opt, 2014. 53(27): p. G33-43]. Images of thin films acquired using DPM are presented.
Author: Alexandru ANGHEL
SiNx thin films were successfully synthesized by nitrogen seeding an Thermionic Vacuum Arc (TVA) silicon plasma. X-Ray Diffraction (XRD) measurements revealed their amorphous structure while their composition as a function of the nitrogen flow was investigated by Rutherford Backscattering Spectrometry (RBS), X-Ray Photoelectron Spectroscopy (XPS) and Fourier Transformed Infrared Spectroscopy (FTIR). The optical band-gap was extracted from UV-VIS spectrophotometry.
Author: Alina Georgiana ILIE
Raman spectroscopy opens a comprehensive perspective regarding vibrational modes sensible correlations with nanomaterial structure and composition. This aspect mostly translates into shifting and broadening of the Raman modes, effects which are usually overlapping. A hybrid approach for nanomaterial evaluation involves the association of Raman spectroscopy with Principal Component Analysis (PCA), which proceeds via eigenvalue decomposition of descriptive data covariance, and quantifies the correlation between sample properties and vibrational modes. The method is usually applied for nanomaterial classification: here, 15 Raman spectra of laser pyrolysis synthesized nanoparticles and L-CVD grown multiwall carbon nanotubes are segregated into four clusters of similar materials. Advanced analysis is used to characterize Sn doped TiO2 nanoparticles and undoped TiO2 nanoparticles, synthesised by laser pyrolysis, with nanocrystallite dimensions varying from 8 to 28 nm. This type of application allows nanocrystallite size evaluation, carbon shell determination or tin concentration quantification, only by measuring the Raman spectrum of the sample. The batch analysis of 138 samples of TiO2 nanoparticles supports the method suitability for rapid nanoparticle characterization. The versatility of this approach is not limited to nanocrystallite size approximation (up to 40 nm) in mixed phase anatase/rutile TiO2, but also for homogeneous microstrained polycrystalline nanosystems characterization. Principal component loadings provide information towards vibrational modes behaviour relative to nanoparticle features and the spectral area relevant for the classification. This in-depth analysis can reveal dependences that are not obvious to classical exploration.
Author: Andrei STOCHIOIU
We present the optimization process for fabrication of Surface-Enhanced Raman Scattering (SERS) substrates with good Raman signal amplification using a picosecond laser and a galvanometric scanner in order to induce periodic structures on a metallic surface. A Lumera (Coherent) Hyperrapid 50 laser was employed in our experiments at 1064 nm wavelength, 8 ps pulse duration, 500 kHz repetition rate and average powers up to 50 W. Aluminum plates were marked with parallel lines at different laser fluences and number of pulses. The obtained surface structures ranged from no modification to large laser ablation. During this process periodic structures named ripples formed on the surface. The resulting plates were analyzed by optical and electronic microscopy in order to find the optimum conditions (laser fluence, number of pulses, distance between laser ablated lines) for large area homogeneous structures. By analyzing the microscopic structure of the ripples we can approximate if the substrate has any chance of being used as a reliable large area SERS substrate. As a second step, we optimize the process of Laser Induced Periodic Surface structures (LIPSS) creation on silver coated aluminium substrates. The silver layer thickness was varied from 50 to 800 nm. The enhancement factor for the optimized SERS substrates will be presented as an average of multiple Raman measurements.
Author: Florin GHERENDI
S-au realizat tranzistori cu filme subțiri (TFT) folosind In2O3 atât pe post de canal cât și pe post de contacte de sursă-drenă și poartă. Structurile TFT au fost realizate prin depunere cu fascicul pulsat de electroni (PED) combinată cu sputtering magnetron RF, folosind măști mecanice pentru patterningul contactelor, canalului și izolatorului. S-au dezvoltat și realizat asemenea măști și pe sistemul TruLaser Cell 3010 din CETAL. Filmele In2O3 depuse în oxigen la presiune mică (10-2 mbar) au o conducție foarte bună (~10-2 -10-3 Ωcm), în timp ce la presiune mare (2x10-2 mbar) au bune proprietăți semiconductoare și rezistivitate mare (peste 1 Ωcm). Au fost realizate TFT-uri prin depunerea canalului In2O3 prin PED în oxigen, fie într-un proces separat – TFT multistrat- la o presiune de lucru mai mare (2x10-2 mbar), fie self-asambat sub mască -într-un singur proces- împreună cu contactele sursă-drenă la presiune de lucru mai mică (10-2 mbar), demonstrându-se că prin sellf-asamblare se obține un canal cu rezistivitate mare, performanțele TFT rezultat fiind superioare.. În această lucrare prezentăm un studiu comparativ al acestor tranzistori, multistrat și self-asamblați, fie folosind un izolator Y2O3 depus magnetron RF pe substrat de sticlă optică, fie hibrizi - folosind hârtie de condensator atât ca substrat cât și ca izolator de poartă. -
Author: Raluca IVAN
Graphene oxide (GO) / transition metal oxide (TMO) semiconductor composite materials are extensively studied for a wide range of applications including sensors, energy storage devices or photocatalysts for the decomposition of organic compounds. Photocatalytic processes are among the most sustainable and environmental friendly technologies for organic pollutants degradation. The photocatalytic efficiency of GO / TMO semiconductor composite materials has been proven to exceed that of bare semiconductor materials. In this work the synthesis of GO / TMO nanocomposite thin films is reported by ultraviolet matrix assisted pulsed laser evaporation. The technique allows for the tuning of the functional groups of graphene oxide and the simultaneous doping when the irradiations are performed in nitrogen atmosphere. The influence of GO / TMO relative concentration ratio and the effect of nitrogen doping on the photocatalytic activity of the layers will be discussed. The photocatalytic properties of the layers are studied through the degradation of organic dye molecules under UV or visible light irradiation. The enhanced photocatalytic efficiency of the hybrid as compared to the reference pure graphene oxide or transition metal oxide layers both under UV and visible light irradiation was attributed to the synergistic effect between oxide nanoparticles and graphene oxide platelets. The recyclability of the layers was also investigated through repetitive degradation of dye solutions.
Author: Cristina NIȚĂ
A novel fast, facile and environmentally friendly one-pot route to prepare 3D-carbon/SiO2 materials as anodes for Li-ion batteries was developed and reported in this work. The influence of heat-treatment temperature (600-1200oC) on the C/SiO2 hybrids characteristics (porosity, structure and SiO2 growth/dispersion) and the electrochemical performances was evaluated. A gradually decrease of the porosity is observed also by increasing the annealing temperature from 600 to 1200oC. Moreover, an interpenetrating hybrid network composed of carbon and amorphous SiO2 homogenous distributed at atomic level was achieved as revealed by STEM-EDX. An excellent cycling capability, with a reversible capacity up to 535 mAh/g at a C/5 constant current rate, in the voltage range 0.01-1.5V (Li/Li+) was obtained for C/SiO2 materials used as anodes for Li-ion batteries. An atypical increase of the capacity during the first 50 cycles followed by stabilization up to 250 cycles was observed. XRD and STEM post-mortem analyses were conducted to get insights on this behavior.
Author: Florin JIPA
Lab-on-a-chip devices are miniaturized platforms used for unconventional cells analyses. They can offer several advantages such us high sensitivity, fast response, low reagent consumption and may facilitate the development of 3D complex structures including “organs-on-chip” architectures. These devices can be fabricated in photosensitive glasses by high repetition rate laser processing with short laser pulses, commonly with femtosecond durations. In this study we demonstrate the successful fabrication of 3D microfluidic structures in Foturan glass by high repetition rate picosecond laser assisted etching (PLAE) using either the 2nd or 3rd harmonics (532 nm or 355 nm wavelength) of a Nd:YAG laser. Critical irradiation doses and ratios of a sequel etching were examined for both wavelengths in order to optimize the processing conditions of PLAE. Controlled fabrication of microfluidic structures consisting of open micro-reservoirs and connecting embedded channels was achieved for both cases. Our study evidenced that transparent materials processing with high repetition rate ps laser pulses based on multi-photon absorption mechanism could be a viable alternative to classical fs micro-fabrication. More importantly, large-area 3D micro/nanofabrication with considerably reduced processing time and production costs will offer great advantage for manufacturing with high repetition rate ps laser pulses.
Author: Cristina Ștefana IOSUB
Cell behaviour, for instance cell adhesion, proliferation and migration potential through biomimetic microenvironments fabricated by laser processing is herein analyzed. In particular, specific geometrical 2D and 3D configurations were created by picosecond laser assisted methods in Foturan photosensitive glass (PG) and in polydimethylsiloxane (PDMS). 3D structures composed of open reservoirs connected through embedded channels were fabricated in the PG by picosecond laser assisted etching whereas the PDMS micro-wells platforms were created by casting using a PG mold tailored by laser irradiation and etching. Human mesenchymal stem cells (MSC) were then monitored by live imaging in PG device under controlled perfusion of fibroblast growth factor (FGF-2). More specifically, a functional microfluidic device with a 3D complex configuration was developed to investigate the potential of controlled nanoliter flow of FGF-2 to induce osteogenic response of MSC. SaOS-2 human osteosarcoma cells were cultured in PDMS micro-wells partly coated with fibronectin and fixed after 2 h, 6h, 18 h and 24 h of seeding. In order to visualize the cell cytoskeleton and evaluate cell adhesion in 3D configurations, the seeded samples were stained with red actin-rhodamine for actin filaments and with blue Hoechst for investigating the cell nucleus. It was noticed that the cells do not adhere on the uncoated area of the sample. Moreover, the confocal images suggested that after 2h the cells fall in the wells while after 6h, 18 h and 24 h, the cells proliferate and migrate to the walls of the micro-wells. Acknowledgements Work supported by grant PNIII-P1-1.1-TE-2016-2084, TE7/2018.
Author: Marian ZAMFIRESCU
The lasers are more and more used in technological steps as tools that replace the traditional processing machines for applications requiring a high degree of precision and reproducibility. At CETAL several laser-based fabrication methods are implemented, such as Direct Laser Writing (DLW) with pico- and femtosecond laser pulses or Laser Additive Manufacturing of 3D structures from metallic powders. Several applications based on laser material processing developed at CETAL will be presented, like laser fabrication of 3D targets for ultraintense laser interactions, micro-optics, laser processing of photopolymers for integrated optics components and laser surface nanopatterning.
Author: Rameez AHMAD
The achievements of the two-photon polymerization based world's highest resolution micro 3D printer "Photonic Professional GT" will be presented. The device offers a defined control on the feature sizes and resolutions ranging from nanometer to micrometer scale and accessible print area of ~ cm2. This versatility has opened new frontiers in the field of photonics, microoptics, microfluidics, life sciences, bio-medical, micromachines and many others. All this is made possible by the advancements in the software and hardware design of the printer as well as high level of materials research that enables the realization of ideas only with few mouse clicks. The decade of trusted use of this technology has found its way to several industrial applications as well. This presentation will therefore, cover the latest advances utilizing this art of 3D microprinting that has made small things matter across the globe.
A Skype presentation from Nanoscribe GmbH, Germany.
Author: Ahmed Kareem Hammood Jaberi
Abstract: Antibiotic resistance is a huge problem of mankind as it is associated with difficulties in treating infections such as pneumonia, tuberculosis, gonorrhea or salmonellosis. Here we present our results in the synthesis and characterization of zein nanoparticles doped with silver and chrom ions. We tested these nanoparticles against an antibiotic resistant strain of Escherichia coli and identified that both of them are effective and especially those doped with chrom. Terahertz spectroscopy measurements performed on nanoparticles incubated with lipids specific to E. coli show a different interaction pattern between the two types of nanoparticles and the lipids.
Author: Razvan Marian MIHALCEA
Abstract: Vibration test facilities, ground based, are needed to reduce the risks of space missions. In this work we present the results of the tests conducted in the vibration laboratory at CETAL over a pair of corner cube retro-reflectors. The equipment utilized is a shaker unit produced by Dongling Technologies with acceleration up to 100G, maximum displacement of 50 mm and maximum velocity of 1.8 m/s. The retro-reflectors must keep their main properties during space launch and reach approximately 20.000 km above the ground level. Tests were performed with respect to European Space Agency technical specifications in order to simulate real space launching conditions. Results revealed mechanical issues of one of the components. Software simulations were as well performed.
Author: SESIUNE POSTERE
Title: PLASMA CRYSTAL ROTATION BY ELECTRON BEAMS
Author: Dorina TICOȘ
Rotation of a plasma crystal induced by the kinetic force of an electron beam was investigated. Melamine formaldehide microparticles of 11 µm were levitated in a radiofrequency discharge at 13,56 MHz. Electrons with an energy of 14 keV determined the rotation of the whole crystal while it kept its hexagonal symetry. Particle Tracking Velocimetry was used to determine the trajectories of the microparticles and their velocities. Analysis of the crystal symetry was made at different times from the first electron beam impact on the crystal.
Title: Proton acceleration in ultra-intense laser interaction with solid targets at CETAL-PW laser
Author: Georgiana GIUBEGA
The laser-driven proton acceleration is a research topic of great interest for all the applications using accelerated particles, due to the smaller acceleration distances and particular beam characteristics. Among their most important applications is hadrontherapy due to the unique properties of the charged particles (protons and other ions, such as Carbon) to penetrate the tissues with small diffusion and deposit their maximum energy right before stopping. Using hadrons for tumors irradiation the healthy tissues are less affected than in X-ray therapy. We investigate proton acceleration in ultra-intense femtosecond laser pulses interaction with thin solid targets, in the TNSA (Target Normal Sheath Acceleration) mechanism. In this regime, protons accelerated behind the target perpendicular to it, exhibit a wide angular distribution of about 25°-30°. Therefore, the use of stacks of radiochromic films (RCF) as particles detectors, placed at optimal distances behind the target, is appropriate for the detection of the entire proton beam in a single shot. We present here the principle of the TNSA mechanism of proton acceleration and the RCF stack detection method. We performed proton acceleration experiments using the following laser parameters: 40 fs pulse duration, average energy of 4 J on different solid targets, e.g. 2 µm Ti and 10 µm Al foils, 20 x 5 µm laser spot. SRIM-2008 simulation code package [1,2] was used to determine the maximum proton energies detected on the RCFs. Acknowledgements: Research funded by IFA under contract no. 27/ELI-RO 2017  J. F. Ziegler, J. P. Biersack and U. Littmark , "The Stopping and Range of Ions in Solids", Pergamon Press, New York, 1985.  J.F. Ziegler (Auth.)-The Stopping and Ranges of Ions in Matter-Pergamon Press (1977)
Title: X-ray and near-infrared excited up-conversion emission properties of Ln doped nanoparticles/ microparticles
Author: Daniel AVRAM
Herein, we present near-infrared to near-infrared up-conversion and X-ray excited luminescence of several Ln (e.g. Er, Tm and Yb) doped nanoparticles. The up-conversion mechanisms are investigated in terms of advanced luminescence spectroscopy with both time and spectral resolution: time-gated up-conversion emission/ excitation spectra and up-conversion emission dynamics. The X-ray induced emission properties are measured in the 450 to 1700 nm range, under varying X-ray debit doses. Under up-conversion excitation at 1500 nm, the emission of Er doped nanoparticles (e.g. Y2O3 and Lu2O3) displays a relative intense emission at 980 nm accounting for up to ~99% of the total emission (for 1% Er doping concentration). Moreover, under X-ray excitation of Er- Y2O3 and Lu2O3, the emission is dominated up to 80% by the near-infrared emission of Er at 1500 nm . Recent results on the near-infrared up-conversion thermometry using Er, Yb - Gd2O2S microparticles are also presented . In all, our investigations reveal interesting visible and near-infrared emission properties of Ln doped nanoparticles/microparticles under both optical and X-ray excitation that render them attractive for bio-imaging in the second/third biological windows as well as photovoltaics, dosimetry and thermometry applications. References:  D. Avram, B. Cojocaru, I. Tiseanu, M. Florea, C. Tiseanu, J. Phys. Chem. C 121(26), 14274-14284 (2017).  D. Avram, C. Tiseanu, Methods and Applications in Fluorescence, 6, 025004 (2018).
Title: Nanocompozite oxidice cu materiale nanocarbonice cu aplicatii in fotonica (sisteme fotovoltaice si laseri)
Author: Bogdan Alexandru Sava
Abstract: Proiectul propune explorarea, optimizarea si demonstrarea potentialului de utilizare la nivel industrial al unor materiale pe baza de grafena nanostructurata, utilizata in diverse morfologii si categorii compozitionale. Tehnologiile inovative care vor fi dezvoltate vizeaza diverse aplicatii: sisteme fotovoltaice, sisteme laser. Se va proiecta si realiza sinteza si caracterizarea de nanocompozite oxidice inovative (sticle borofosfatice, ZnO) cu oxizi de grafena (GO, rGO) pentru aplicatii in sisteme fotovoltaice si laseri. Proiectul isi propune dezvoltarea de sisteme nanocompozite oxidice cu materiale nanocarbonice pentru noi aplicatii, prin trei metode: (i)Sinteze sol-gel de filme oxidice compozite cu materiale nanocarbonice, pentru conductori transparenti in sisteme fotovoltaice; (ii)Sinteze prin tehnica topire/turnare/sinterizare de materiale bloc borofosfatice cu materiale nanocarbonice, optimizarea transmisiei optice, termice si electrice pentru aplicatii in sisteme laser; (iii)Sinteze de filme subtiri prin Magnetron Sputtering (MS)/ MAPLE pentru aplicatii in sisteme laser.