Linac Coherent Light Source at SLAC National Accelerator Laboratory
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Caso Relativamente Recente
Perché chiamiamo “fondamentale” la Cenerentola della ricerca? (di M. Brunori) Neanche nel Pnrr si trovano speranze di cambiamento e iniziative coraggiose per la ricerca di base. Ma nelle scienze della vita non sono rare le scoperte nate da progetti di ricerca curiosity driven che richiedono tempo per portare risultati Soci dell'Accademia dei Lincei. (a cura di Maurizio Brunori, Prof. emerito di Chimica e Biochimica, Sapienza Università di Roma, Presidente emerito della Classe di Scienze FMN dell’Accademia dei Lincei) Nelle scienze della vita non sono infrequenti le scoperte innovative nate da progetti di ricerca di base, iniziati per cercare di comprendere qualche importante proprietà di un essere vivente, misteriosa ma ovviamente necessaria se è stata conservata nel corso dell’evoluzione. Questi progetti sono quelli che si iniziano per curiosità intellettuale, ma richiedono libertà di iniziativa, impegno pluriennale e molto coraggio in quanto di difficile soluzione. Un successo straordinario noto a molti è quello ottenuto dieci anni fa da due straordinarie ricercatrici, Emmanuelle Charpentier e Jennifer Doudna; che a dicembre hanno ricevuto dal Re di Svezia il Premio Nobel per la Chimica con la seguente motivazione: “for the development of a new method for genome editing”. Nel 2018 in occasione di una conferenza magistrale che la Charpentier tenne presso l’Accademia Nazionale dei Lincei, avevo pubblicato sul Blog di HuffPost un pezzo per commentare l’importanza della scoperta di CRISPR/Cas9, un kit molecolare taglia-e-cuci che consente di modificare con precisione ed efficacia senza precedenti il genoma di qualsiasi essere vivente: batteri, piante, animali, compreso l’uomo. NOBEL PRIZE Nobel Chimica Non era mai accaduto che due donne vincessero insieme il Premio Nobel. -
Neutron Instrumentation
Neutron Instrumentation Oxford School on Neutron Scattering 5th September 2019 Ken Andersen Summary • Neutron instrument concepts – time-of-flight – Bragg’s law • Neutron Instrumentation – guides – monochromators – shielding – detectors – choppers – sample environment – collimation • Neutron diffractometers • Neutron spectrometers 2 The time-of-flight (TOF) method distance Δt time Diffraction: Bragg’s Law Diffraction: Bragg’s Law Diffraction: Bragg’s Law Diffraction: Bragg’s Law Diffraction: Bragg’s Law Diffraction: Bragg’s Law λ = 2d sinθ Diffraction: Bragg’s Law λ = 2d sinθ 2θ Reflection: Snell’s Law incident reflected n=1 θ θ’ refracted n’<1 Reflection: Snell’s Law incident reflected n=1 θ θ’ refracted θ’=0: critical angle of total n’<1 reflection θc Reflection: Snell’s Law incident reflected n=1 θ θ’ refracted θ’=0: critical angle of total n’<1 reflection θc cosθc = n' n = n' Nλ2b n' = 1− ⇒ θc = λ Nb/π 2π ≈ − 2 cosθc 1 θc 2 Reflection: Snell’s Law incident reflected n=1 θ θ’ refracted θ’=0: critical angle of total n’<1 reflection θc cosθc = n' n = n' 2 for natural Ni, Nλ b n' = 1− ⇒ θc = λ Nb/π 2π θc = λ[Å]×0.1° cosθ ≈ 1− θ2 2 c c -1 Qc = 0.0218 Å Neutron Supermirrors Courtesy of J. Stahn, PSI Neutron Supermirrors Courtesy of J. Stahn, PSI Neutron Supermirrors Courtesy of J. Stahn, PSI Neutron Supermirrors λ Reflection: θc(Ni) = λ[Å] × 0.10° c λ 1 Multilayer: θc(SM) = m × λ[Å] × 0.10° λ 2 λ 3 λ 4 } d 1 } d 2 } d3 } d4 18 Neutron Supermirrors λ Reflection: θc(Ni) = λ[Å] × 0.10° c λ 1 Multilayer: θc(SM) = m × λ[Å] × 0.10° λ 2 -
Neutron Spin Echo Spectroscopy
Neutron Spin Echo Spectroscopy Peter Fouquet [email protected] Institut Laue-Langevin Grenoble, France Oxford Neutron School 2017 What you are supposed to learn in this tutorial 1. The length and time scales that can be studied using NSE spectroscopy 2. The measurement principle of NSE spectroscopy 3. Discrimination techniques for coherent, incoherent and magnetic dynamics 4. To which scientific problems can I apply NSE spectroscopy? NSE-Tutorial Mind Map Quantum Mechanical Model Resonance Spin-Echo Classical Model Measurement principle “4-point Echo” NSE spectroscopy Instrument Frustrated Components Magnets Bio- molecules Time/Space Map NSE around Surface the globe Diffusion Science Cases Paramagnetic Spin Echo Experiment planning and Interpretation Diffusion Glasses Polymers Models Coherent and Incoherent Scattering Data Treatment The measurement principle of neutron spin echo spectroscopy (quantum mechanical model) • The neutron wave function is split by magnetic fields • The 2 wave packets arrive at magnetic coil 1 magnetic coil 2 polarised sample the sample with a time neutron difference t • If the molecules move between the arrival of the first and second wave packet then coherence is lost • The intermediate scattering t λ3 Bdl function I(Q,t) reflects this ∝ loss in coherence strong wavelength field integral dependence Return The measurement principle of neutron spin echo spectroscopy Dynamic Scattering NSE spectra for diffusive motion Function S(Q,ω) G(R,ω) I(Q,t) = e-t/τ Fourier Transforms temperature up ⇒ τ down Intermediate VanHove -
High Resolution Spectroscopy with the Neutron Resonance Spin Echo Method
High Resolution Spectroscopy with the Neutron Resonance Spin Echo Method vorgelegt von Diplom-Physiker Felix Groitl aus Erlangen von der Fakultät II - Mathematik und Naturwissenschaften der Technischen Universität Berlin zur Erlangung des akademischen Grades Doktor der Naturwissenschaften Dr. rer. nat. genehmigte Dissertation Promotionsausschuss: Vorsitzender: Prof. Dr. M. Kneissl Gutachter: Prof. Dr. D. A. Tennant Gutachter: Prof. Dr. P. Böni Gutachter: Dr. K. Habicht Tag der wissenschaftlichen Aussprache: 18.12.2012 Berlin 2013 D 83 Abstract The first part of this thesis is dedicated to explore new territory for high resolution Neu- tron Resonance Spin Echo (NRSE) spectroscopy beyond measuring lifetimes of elementary excitations. The data analysis of such experiments requires a detailed model for the echo amplitude as a function of correlation time. The model also offers guidance for planning NRSE experiments in terms of a sensible choice of parameters and allows predicting quan- titatively the information content of NRSE spectroscopy for line shape analysis or energy level separation. Major generalizations of the existing formalism, developed in this thesis, allow for violated spin echo conditions, arbitrary local gradient components of the dispersion surface and detuned parameters of the background triple axis spectrometer (TAS) giving rise to important additional depolarizing effects, which have been neglected before. Fur- thermore, the formalism can now be applied to any crystal symmetry class. The model was successfully tested by experiments on phonons in a high quality single crystal of Pb and the results demonstrate the stringent necessity to consider second order depolarization effects. The formalism was subsequently extended to analyze mode doublets. As a major step for- ward, detuning effects for both modes are taken into account here. -
Nobel Laureates Endorse Joe Biden
Nobel Laureates endorse Joe Biden 81 American Nobel Laureates in Physics, Chemistry, and Medicine have signed this letter to express their support for former Vice President Joe Biden in the 2020 election for President of the United States. At no time in our nation’s history has there been a greater need for our leaders to appreciate the value of science in formulating public policy. During his long record of public service, Joe Biden has consistently demonstrated his willingness to listen to experts, his understanding of the value of international collaboration in research, and his respect for the contribution that immigrants make to the intellectual life of our country. As American citizens and as scientists, we wholeheartedly endorse Joe Biden for President. Name Category Prize Year Peter Agre Chemistry 2003 Sidney Altman Chemistry 1989 Frances H. Arnold Chemistry 2018 Paul Berg Chemistry 1980 Thomas R. Cech Chemistry 1989 Martin Chalfie Chemistry 2008 Elias James Corey Chemistry 1990 Joachim Frank Chemistry 2017 Walter Gilbert Chemistry 1980 John B. Goodenough Chemistry 2019 Alan Heeger Chemistry 2000 Dudley R. Herschbach Chemistry 1986 Roald Hoffmann Chemistry 1981 Brian K. Kobilka Chemistry 2012 Roger D. Kornberg Chemistry 2006 Robert J. Lefkowitz Chemistry 2012 Roderick MacKinnon Chemistry 2003 Paul L. Modrich Chemistry 2015 William E. Moerner Chemistry 2014 Mario J. Molina Chemistry 1995 Richard R. Schrock Chemistry 2005 K. Barry Sharpless Chemistry 2001 Sir James Fraser Stoddart Chemistry 2016 M. Stanley Whittingham Chemistry 2019 James P. Allison Medicine 2018 Richard Axel Medicine 2004 David Baltimore Medicine 1975 J. Michael Bishop Medicine 1989 Elizabeth H. Blackburn Medicine 2009 Michael S. -
October 2017 Current Affairs
Unique IAS Academy – October 2017 Current Affairs 1. Which state to host the 36th edition of National Games of India in 2018? [A] Goa [B] Assam [C] Kerala [D] Jharkhand Correct 2. Which Indian entrepreneur has won the prestigious International Business Person of the Year award in London for innovative IT solutions? [A] Birendra Sasmal [B] Uday Lanje [C] Madhira Srinivasu [D] Ranjan Kumar 3. The United Nations‟ (UN) International Day of Non-Violence is observed on which date? [A] October 4 [B] October 1 [C] October 2 [D] October 3 4. Which country to host the 6th edition of World Government Summit (WGS)? 0422 4204182, 9884267599 1st Street, Gandhipuram Coimbatore Page 1 Unique IAS Academy – October 2017 Current Affairs [A] Israel [B] United States [C] India [D] UAE 5. Who of the following has/have won the Nobel Prize in Physiology or Medicine 2017? [A] Jeffrey C. Hall [B] Michael Rosbash [C] Michael W. Young [D] All of the above 6. Which state government has launched a state-wide campaign against child marriage and dowry on the occasion of Mahatma Gandhi‟s birth anniversary? [A] Odisha [B] Bihar [C] Uttar Pradesh [D] Rajasthan 7. The 8th Conference of Association of SAARC Speakers and Parliamentarians to be held in which country? [A] China [B] India [C] Sri Lanka [D] Nepal Correct 8. Which committee has drafted the 3rd National Wildlife Action Plan (NWAP) for 2017- 2031? [A] Krishna Murthy committee [B] JC Kala committee 0422 4204182, 9884267599 1st Street, Gandhipuram Coimbatore Page 2 Unique IAS Academy – October 2017 Current Affairs [C] Prabhakar Reddy committee [D] K C Patan committee 9. -
LCLS: the First Experiments
LCLS THE FIRST EXPERIMENTS September 2000 ii Table of Contents First Scientific Experiments for the LCLS .....................................................v Atomic Physics Experiments ..........................................................................1 Plasma and Warm Dense Matter Studies......................................................13 Structural Studies on Single Particles and Biomolecules .............................35 Femtochemistry.............................................................................................63 Studies of Nanoscale Dynamics in Condensed Matter Physics....................85 X-ray Laser Physics ....................................................................................101 Appendix 1: Committee Members..............................................................113 iii iv First Scientific Experiments for the LCLS The Scientific Advisory Committee (SAC) for the Linac Coherent Light Source (LCLS) has selected six scientific experiments for the early phase of the project. The LCLS, with proposed construction in the 2003-2006 time frame, has been designed to utilize the last third of the existing Stanford Linear Accelerator Center (SLAC) linac. The linac produces a high-current 5- 15 GeV electron beam that is bunched into 230 fs slices with a 120 Hz repetition rate. When traveling through a sufficiently long (of order of 100 m) undulator, the electron bunches will lead to self amplification of the emitted x-ray intensity constituting an x-ray free electron laser (XFEL). If funded as proposed, the LCLS will be the first XFEL in the world, operating in the 800-8,000 eV energy range. The emitted coherent x-rays will have unprecedented brightness with 1012-1013 photons/pulse in a 0.2-0.4% energy bandpass and an unprecedented time structure with a design pulse length of 230 fs. Studies are under way to reduce the pulse length to tens of femtoseconds. This document presents descriptions of the early scientific experiments selected by SAC in the spring of 2000. -
Neutron Spin Echo Spectroscopy
Neutron Spin Echo Spectroscopy Catherine Pappas TU Delft uncluding slides and animations from R. Gähler, R. Cywinski, W. Bouwman Berlin Neutron School - 30.3.09 from the source to the detector sample and source moderator PSΕ ΙΝ sample environment PSE OUT detector Neutron flux φ = Φ η dE dΩ / 4π source flux intensity field of neutron distribution losses instrumentation definition of the beam : Q, E and polarisation Berlin Neutron School - 30.3.09 Neutron Spin Echo why ? very high resolution how ? using the transverse components of beam polarization Larmor precession Berlin Neutron School - 30.3.09 Neutron Spin Echo I: polarized neutrons - Larmor precession II: NSE : Larmor precession III: NSE : semi-classical description IV: movies V: quantum mechanical approach VI: examples VII: NSE and structure Berlin Neutron School - 30.3.09 Neutron Spin Echo I: polarized neutrons - Larmor precession II: NSE : classical description III: NSE : quantum mechanical description IV: movies V: NSE and coherence VI: exemples VII: NSE and structure Berlin Neutron School - 30.3.09 Polarized Neutrons ๏ polarizer ๏ analyzer magnetic field (guide - precession) magnetic field Neutron Neutron source polarizer B P analyzer detector flipper sample Berlin Neutron School - 30.3.09 Longitudinal polarization analysis Why longitudinal ???? after F. Tasset because we apply a magnetic field and measure the Berlinprojection Neutron School of - 30.3.09 the polarization vector along this field Larmor Precession Motion of the polarization of a neutron beam in a magnetic field dµ = γ (µ -
2017 Nobel Prize in Chemistry Awarded to Prof. Joachim Frank
2017 Nobel Prize in Chemistry Awarded to Prof. Joachim Frank October 4, 2017 Columbia University congratulates Joachim Frank, PhD, professor of biochemistry and molecular biophysics and of biological sciences, a winner of the Nobel Prize in Chemistry 2017, shared with Richard Henderson and Jacques Dubochet “for developing cryo-electron microscopy for the high-resolution structure determination of biomolecules in solution.” Joachim Frank's Bio Joachim Frank, PhD, is a professor of biochemistry and molecular biophysics at Columbia University Medical Center and biological sciences at Columbia University. Dr. Frank helped pioneer the development of cryo-electron microscopy, a technique used to reveal the structures of large organic molecules at high resolution. Dr. Frank developed the necessary computational methods for reconstructing the three- dimensional shape of biological molecules from thousands of two-dimensional images of molecules, methods employed today by most structural biologists who use electron microscopy. Cryo-electron microscopy is commonly used by structural biologists to study the molecular processes inside cells that drives protein synthesis. Using this technique, Dr. Frank has made important discoveries about the interactions between ribosomes (complex molecules that serve as the ‘factories’ of the cell) and other proteins in the cell. In a 2013 paper in Nature, Dr. Frank uncovered unique details about ribosomes from the parasite that causes African sleeping sickness that could lead to the development of new drugs for this disease. In another Nature paper later that year, he revealed how viral RNA commandeers the ribosome of the virus’s host to produce new viruses. Dr. Frank was born in Germany during World War II. -
Neutron Spectroscopy Study of the Diffusivity of Hydrogen in Mos2
PCCP View Article Online PAPER View Journal | View Issue Neutron spectroscopy study of the diffusivity of hydrogen in MoS2 Cite this: Phys. Chem. Chem. Phys., 2021, 23, 7961 Vitalii Kuznetsov, ab Wiebke Lohstroh,c Detlef Rogalla,d Hans-Werner Becker,d Thomas Strunskus,e Alexei Nefedov, f Eva Kovacevic,g Franziska Traegerb and Peter Fouquet *a The diffusion of hydrogen adsorbed inside layered MoS2 crystals has been studied by means of quasi- elastic neutron scattering, neutron spin-echo spectroscopy, nuclear reaction analysis, and X-ray Received 29th September 2020, photoelectron spectroscopy. The neutron time-of-flight and neutron spin-echo measurements Accepted 18th December 2020 demonstrate fast diffusion of hydrogen molecules parallel to the basal planes of the two dimensional DOI: 10.1039/d0cp05136e crystal planes. At room temperature and above, this intra-layer diffusion is of a similar speed to the surface diffusion that has been observed in earlier studies for hydrogen atoms on Pt surfaces. A significantly rsc.li/pccp slower hydrogen diffusion was observed perpendicular to the basal planes using nuclear reaction analysis. Creative Commons Attribution-NonCommercial 3.0 Unported Licence. 1 Introduction in order to replace the expensive platinum, which is widely used today. Diffusion of molecules on surfaces is crucial for a range of Molybdenum disulphide, MoS2, has shown promising beha- chemical processes, such as catalysis or sensing, but it remains viour as a catalyst in the hydrogen evolution reaction (HER),6–10 extremely difficult to observe experimentally on atomic length which is completely in line with its known activity for hydro- scales. This is particularly true for the case of light molecules genation reactions. -
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HUMBOLDT No. 108 / 2018 No. KOSMOSResearch – Diplomacy – Internationality DEUTSCHE VERSION: BITTE WENDEN Coming to change Ten years of Alexander von Humboldt Professorships ALL LOVE EACH OTHER THERE’S SOMETHING WRONG HERE The advantages of polygamy and How social media can make science better why it so seldom works Ten years of Alexander von Humboldt Professorships With a value of five million euros, the Alexander von Humboldt Professorship is the most highly-endowed research award in Germany and draws top international researchers to German universities. It is financed by the Federal Ministry of Education and Research. David Ausserhofer David / www.humboldt-professur.de/en Photo: Humboldt Foundation Humboldt Photo: Photo: Fati Aziz, Fotolia / preto_perola HUMBOLDTIANS IN PRIVATE MY (NON-)SELFIE WITH THE GERMAN PRESIDENT Hello, can you see the guy at the back of the pic with the engaging smile? That’s me. I’m surrounded by hundreds of Humboldtians at the Humboldt Foundation’s Annual Meeting in the beautiful grounds of Schloss Bellevue, the main residence of the German head of state in Berlin. Federal President Frank-Walter Steinmeier just held a speech welcoming his guests. And now we are all waiting to meet him per- sonally and – best case – get a photo taken together. Of course, not everyone will be so lucky. After all, the President doesn’t have all day. Well, in the end, I at least, was not successful – or that’s what I orig- inally thought. After shaking countless hands and posing for as many selfies, the President took his leave without having a photo taken with me. -
(ATR–FTIR) Spectroscopy, Micro–Attenuated Total Reflectance Fourier
Organic and Medicinal Chemistry International Journal ISSN 2474-7610 Image Article Organic & Medicinal Chem IJ Volume 6 Issue 1 - March 2018 Copyright © All rights are reserved by Alireza Heidari DOI: 10.19080/OMCIJ.2018.06.555677 Fourier Transform Infrared (FTIR) Spectroscopy, Attenuated Total Reflectance Fourier Transform Infrared (ATR–FTIR) Spectroscopy, Micro–Attenuated Total Reflectance Fourier Transform Infrared (Micro–ATR–FTIR) Spectroscopy, Macro–Attenuated Total Reflectance Fourier Transform Infrared (Macro–ATR–FTIR) Spectroscopy, Two–Dimensional Infrared Correlation Spectroscopy, Linear Two–Dimensional Infrared Spectroscopy, Non–Linear Two– Dimensional Infrared Spectroscopy, Atomic Force Microscopy Based Infrared (AFM–IR) Spectroscopy, Infrared Photodissociation Spectroscopy, Infrared Correlation Table Spectroscopy, Near– Infrared Spectroscopy (NIRS), Mid–Infrared Spectroscopy (MIRS), Nuclear Resonance Vibrational Spectroscopy, Thermal Infrared Spectroscopy and Photothermal Infrared Spectroscopy Comparative Study on Malignant and Benign Human Cancer Cells and Tissues under Synchrotron Radiation with the Passage of Time Alireza Heidari* Faculty of Chemistry, California South University, USA Submission: February 26, 2018; Published: March 29, 2018 *Corresponding author: Alireza Heidari, Faculty of Chemistry, California South University, 14731 Comet St. Irvine, CA 92604, USA, Email: Abbreviations: FTIR : Fourier Transform Infrared; ATR-FTIR: Attenuated Total Reflectance Fourier Transform Infrared; Micro-ATR-FTIR: Micro- Attenuated