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Dan Claes University of Nebraska-Lincoln Messages From Deep Space Deep Underground The Henderson Mine Project Thursday, May 4, 2006
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Henri Becquerel (1852-1908) received the 1903 Nobel Prize in Physics for the discovery of natural radioactivity. Wrapped photographic plate showed clear silhouettes, when developed, of the uranium salt samples stored atop it. 1896 While studying the photographic images of various fluorescent & phosphorescent materials, Becquerel finds potassium-uranyl sulfate spontaneously emits radiation capable of penetrating thick opaque black paper aluminum plates copper plates Exhibited by all known compounds of uranium (phosphorescent or not) and metallic uranium itself.
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In ordinary photographic applications light produces spots of submicroscopic silver grains a fast charged particle can leave a trail of individual Ag grains 1/1000 mm (1/25000 in) diameter grains plates coated with thick emulsions (gelatins carrying silver bromide crystals) clearly trace the tracks of charged particles
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1898 Marie Curie discovers thorium ( 90 Th) Together Pierre and Marie Curie discover polonium ( 84 Po) and radium ( 88 Ra) 1899 Ernest Rutherford identifies 2 distinct kinds of rays emitted by uranium - highly ionizing, but completely absorbed by 0.006 cm aluminum foil or a few cm of air - less ionizing, but penetrate many meters of air or up to a cm of aluminum. 1900 P. Villard finds in addition to rays, radium emits - the least ionizing, but capable of penetrating many cm of lead, several feet of concrete
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B-field points into page 1900-01 Studying the deflection of these rays in magnetic fields, Becquerel and the Curies establish rays to be charged particles
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1900-01 Using the procedure developed by J.J. Thomson in 1887 Becquerel determined the ratio of charge q to mass m for : q/m = 1.76×10 11 coulombs/kilogram identical to the electron! : q/m = 4.8×10 7 coulombs/kilogram 4000 times smaller!
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Hess lands following a historic 5,300 meter flight. August 7, 1912 National Geographic photograph 1911-12 Austrian physicist Victor Hess, of the Vienna University, and 2 assistants, carried Wulf ionization chambers up in a series of hydrogen balloon flights. taking ~hour long readings at several altitudes both ascending and descending radiation more intense above 150 meters than at sea level intensity doubled between 1000 m to 4000 m increased continuously through 5000 meters Dubbed this “high” level radiation Höhenstrahlung
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50 m Cosmic ray strikes a nucleus within a layer of photographic emulsion 1937 Marietta Blau and Herta Wambacher report “stars” of tracks resulting from cosmic ray collisions with nuclei within the emulsion
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1936 Millikan’s group shows at earth’s surface cosmic ray showers are dominated by electrons, gammas, and X-particles capable of penetrating deep underground (to lake bottom and deep tunnel experiments) and yielding isolated single cloud chamber tracks primary proton
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1937 Street and Stevenson 1938 Anderson and Neddermeyer determine X-particles are charged have 206× the electron’s mass decay to electrons with a mean lifetime of 2 sec 0.000002 sec the muon, X ee
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Nature 163, 82 (1949) C.F.Powell, P.H. Fowler, D.H.Perkins Nature 159, 694 (1947) 1947 Lattes, Muirhead, Occhialini and Powell observe pion decay Cecil Powell ( 1947 ) Bristol University
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consistently ~600 microns (0.6 mm)
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The Cosmic Ray Energy Spectrum Cosmic Ray Flux Energy (eV) (1 particle per m 2 -sec) (1 particle per m 2 -year) (1 particle per km 2 -year)
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Colliding galaxies Active galactic nucleus Two possible sources of the highest energy cosmic rays
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m2m2 Before the explosion: v o = 0 m1m1 v1v1 v2v2 Mass, M After the explosion: p = 0 p gas p rocket p i = 0 = p f p gas = – p rocket = p gas + p rocket
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A cannon rests on a railroad flatcar with a total mass of 1000 kg. When a 10 kg cannon ball is fired left at a speed of 50 m/sec, as shown, what is the speed of the flatcar? A) 0 m/s B) ½ m/s to the right C) 1 m/s to the left D) 20 m/s to the right
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For these two vehicles to be stopped dead in their tracks by a collision at this intersection A) They must have equal mass B) They must have equal speed C) both A snd B D) is IMPOSSIBLE
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650 kg 10 m/sec 500 kg 20 m/sec Car A has a 650 kg mass and is traveling east at 10 m/sec. Car B has a 500 kg mass and is traveling north 20 m/sec. The two cars collide, and lock bumpers. Neglecting friction which arrow best represents the direction the combined wreck travels? A B C
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A bomb at rest explodes into four fragments. The momentum vectors for three of the fragments are shown. Which arrow below best represents the momentum vector of the fourth fragment? ?
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?
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- decay - decay EE = mc 2
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Some Alpha Decay Energies and Half-lives Isotope KE (MeV) 1/2 (sec -1 ) 232 Th4.011.4 10 10 y 1.6 10 18 238 U4.194.5 10 9 y 4.9 10 18 230 Th4.698.0 10 4 y 2.8 10 13 238 Pu5.5088 years 2.5 10 10 230 U5.8920.8 days 3.9 10 7 220 Rn6.2956 seconds 1.2 10 2 222 Ac7.01 5 seconds 0.14 216 Rn8.0545.0 sec 1.5 10 212 Po8.780.30 sec 2.3 10 216 Rn8.780.10 sec 6.9 10
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B Before decay: After decay: Potassium nucleus A 1930 Series of studies of nuclear beta decay, e.g., Potassium goes to calcium 19 K 40 20 Ca 40 Copper goes to zinc 29 Cu 64 30 Zn 64 Boron goes to carbon 5 B 12 6 C 12 Tritium goes to helium 1 H 3 2 He 3
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1932 Once the neutron was discovered, included the more fundamental n p + e For simple 2-body decay, conservation of energy and momentum demand both the recoil of the nucleus and energy of the emitted electron be fixed (by the energy released through the loss of mass) to a single precise value. but this only seems to match the maximum value observed on a spectrum of beta ray energies! E e = (m A 2 - m B 2 + m e 2 )c 2 /2m A
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No. of counts per unit energy range Electron kinetic energy in KeV 51015200 The beta decay spectrum of tritium ( H He). Source: G.M.Lewis, Neutrinos (London: Wykeham, 1970), p.30)
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Energy spectrum of beta decay electrons from 210 Bi Kinetic energy, MeV Intensity
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-decay spectrum for neutrons Electron kinetic energy in MeV
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1932 n p + e + charge0 +1 1 ? mass 939.56563 938.27231 0.51099906 MeV MeV MeV neutrino mass < 5.1 eV < m e /100000 ??? neutrino 0 ? the Fermi-Kurie plot. The Fermi-Kurie plot looks for any gap between the observed spectrum and the calculated T max spin ½½½ ? <0.78232 MeV 0 ½
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Niels Bohr hypothesized some new quantum mechanical restriction on the principle of energy conservation, but Pauli couldn’t buy that: Wolfgang Pauli 1900-1958
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Dear Radioactive Ladies and Gentlemen, as the bearer of these lines, to whom I graciously ask you to listen, will explain to you in more detail, how because of the "wrong" statistics of the N and Li 6 nuclei and the continuous beta spectrum, I have hit upon a desperate remedy to save the "exchange theorem" of statistics and the law of conservation of energy. Namely, the possibility that there could exist in the nuclei electrically neutral particles, that I wish to call neutrons, which have spin 1/2 and obey the exclusion principle and which further differ from light quanta in that they do not travel with the velocity of light. The mass of the neutrons should be of the same order of magnitude as the electron mass and in any event not larger than 0.01 proton masses. The continuous beta spectrum would then become understandable by the assumption that in beta decay a neutron is emitted in addition to the electron such that the sum of the energies of the neutron and the electron is constant... I agree that my remedy could seem incredible because one should have seen those neutrons much earlier if they really exist. But only the one who dare can win and the difficult situation, due to the continuous structure of the beta spectrum, is lighted by a remark of my honoured predecessor, Mr Debye, who told me recently in Bruxelles: "Oh, It's well better not to think to this at all, like new taxes". From now on, every solution to the issue must be discussed. Thus, dear radioactive people, look and judge. Unfortunately, I cannot appear in Tubingen personally since I am indispensable here in Zurich because of a ball on the night of 6/7 December. With my best regards to you, and also to Mr Back. Your humble servant. W. Pauli, December 1930
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"I have done a terrible thing. I have postulated a particle that cannot be detected."
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1953, 1956, 1959 Savannah River (1000-MWatt) Nuclear Reactor in South Carolina looked for the inverse of the process: n p + e- + neutrino p + neutrino n + e + Cowan & Reines with estimate flux of 5 10 13 neutrinos/cm 2 -sec observed 2-3 p + neutrino events/hour n + neutrino p + e- We have never observed What does that tell us?
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The Nuclear pp cycle producing energy in the sun 6 protons 4 He + 6 + 2 e + 2p 26.7 MeV Begins with the reaction 0.26 MeV neutrinos
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500 trillion solar neutrinos every second!
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+ energy always predictably fixed by E Under the influence of a magnetic field simple 2-body decay! + + + neutrino? charge +1 +1 ? spin 0 ½ ? 0½0½
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n p + e + neutrino? + + + neutrino? Then - e - + neutrino? ??? As in the case of decaying radioactive isotopes, the electrons’s energy varied, with a maximum cutoff (whose value was the 2-body prediction) 3 body decay! p e e 2 neutrinos
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1962 Lederman,Schwartz,Steinberger Brookhaven National Laboratory using a as a source of antineutrinos and a 44-foot thick stack of steel (from a dismantled warship hull) to shield everything but the ’s found 29 instances of + p + + n but none of + p e + + n 1988 Nobel Prize in Physics "for the neutrino beam method and the demonstration of the doublet structure of the leptons through the discovery of the muon neutrino"
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1967 built at Brookhaven labs 615 tons of tetrachloroethylene Neutrino interaction 37 Cl 37 Ar (radioactive isotope, ½ = 35 days) Chemically extracting the 37 Ar, its radioactivity gives the number of neutrino interactions in the vat (thus the solar neutrino flux). ResultsResults: Collected data 1969-1993 (24 years!!) gives a mean of 2.5±0.2 SNU while theory predicts 8 SNU (1 SNU = 1 neutrino interaction per second for 10E+36 target atoms). This is a neutrino deficit of 69%. Homestake Mine Experiment
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The energy spectrum of solar neutrinos predicted by the BP04 solar model. For continuum sources, the neutrino fluxes are given in number of neutrinos cm -2 s -1 MeV -1 at the Earth's surface. For line sources, the units are number of neutrinos cm -2 s -1. Total theoretical uncertainties are shown for each source. The difficult to detect CNO neutrino fluxes have been omitted in this plot. Solar models predict the spectrum and flux of solar neutrinos reaching the earth
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The Solar Neutrino Problem The rate of detection of solar e ’s from is 3 smaller than expected!
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Is the sun’s core cooler than we thought? 6% Is it a different age than we had assumed? New and extraordinarily precise measurements of “solar sound speeds” 1998 small oscillations in spectral line strengths studied by solar seismologists due to pressure waves traversing the solar volume confirm the predictions of internal temperature and pressure by standard solar models to with 0.1%
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Atmospheric Neutrino Detection all showers start e (all K s decaying rapidly into s) with s and Kaons e e e e e → + Each pion decays by → e + e + and each muon decays by Note: at sea level N N e = 2
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One detector measures this significantly more accurately than any other SuperKamiokande They find R sub-GeV = 0.63 0.06 R multi-GeV = 0.65 0.09 Given the time dilation of muon lifetimes (and the probabilistic nature of their decays) we can still calculate/simulate the ratio we expect to observe at the ground, and compare:
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“Evidence for an oscillatory signature in atmospheric neutrino oscillation” Y. Ashie, et. al. (the Super-Kamiokande Collaboration) Phys. Rev. Lett. 93, 101801 (2004).
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Underground Neutrino Observatory The proposed next-generation underground water Čerenkov detector to probe physics beyond the sensitivity of the highly successful Super-Kamiokande detector in Japan
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The SuperK detector is a water Čerenkov detector 40 m tall 40 m diameter stainless steel cylinder containing 50,000 metric tons of ultra pure water The detector is located 1 kilometer below Mt. Ikenoyama inside the Kamioka zinc mine.
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The main sensitive region is 36 m high, 34 m in dia viewed by 11,146 inward facing Hamamatsu photomultiplier tubes surrounding 32.5 ktons of water
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Underground Neutrino Observatory 650 kilotons active volume: 440 kilotons 20 times larger than Super-Kamiokande major components: photomultiplier tubes, excavation, water purification system. $500M The optimal detector depth to perform the full proposed scientific program of UNO 4000 meters-water-equivalent or deeper
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DUSEL: A National Science Foundation initiative to establish a national underground laboratory for research in physics, Earth and environmental sciences, civil and Mining engineering, and the Biosciences. “The science cuts across disciplines and Directorates (ENG, GEO, and MPS) and provides opportunities for transformational breakthroughs and to educate the scientists & engineers of the 21stcentury” Michael S. Turner, Assistant Director for Mathematics and Physical Science Division (NSF) Icicle Creek Cascades, WA Henderson Mine Empire, CO Homestake Mine Lead, SD Kimballton Mine Giles Co.,West VA WIPP Carlsbad, NM Soudan Mine Soudan, MN Mount San Jacinto, CA
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Lt Blue proposed access ramps Green exploratory drill holes Dk Blue – Geo research areas Red – Added geo access Geo-outposts will explore below the ore body! Ore Geology, Magmatic- Hydrothermal Processes, and Petrogeneis Hydrogeolog y Coupled Processes Geophysics Geophysical imaging Stress in the earth
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* SASFiG-9 (isolated) Detected within a water-bearing dyke/fracture at 3.2 Km depth. strictly anaerobic; iron-reducer optimal growth temperature = 60 o C virgin rock temp = ~ 45 o C * SASFiG-1 SASFiG-2 SASFiG-3 SASFiG-4 SASFiG-5 SASFiG-6 SASFiG-7 SASFiG-9 SASFiG-8 * image courtesy of Gordon Southam What do we know so far? New, unusual microbes and sequences indicative of ancestral linkages, less evolved sequences (early life?), biomedical and biotech applications Novel bacterial lineages that appear unique to the South African deep- subsurface: South Africa Subsurface Firmicutes Groups (SASFiG) 1 m
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Major Questions in Geomicrobiology How deeply does life extend into the Earth? What are the lower limits of life in the biosphere? Temperature, Pressure, Nutrients/ energy Fig. 2 of Earthlab report 10 1 10 3 10 5 10 7 01 2345601 23456
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Henderson DUSEL Biology Questions What ’ s down there? Bacteria? Archaea? Eukaryotes? Viruses? Did life 1 st evolve deep underground, and spread to the surface? Are the most ancient lineages of life found deep below the surface? What are the genetic and physiological adaptations to such “ life in the slow lane ” ? How do microbes harness energy (interaction of water and rock?) Isotopic analyses to infer chemical or biological origin Genomics and proteomics — search for new genes, proteins (to include functional gene analyses, geochemical analyses, and stable- isotope analyses to identify sources of energy) What limits life? Depth, temperature, pH, substrate, energy source? Survey the biodiversity: “ what ” is “ where ” ?
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Geobiology Opportunities and Facilities at Henderson Near Term: S2 project -- exploratory borehole(s) Long Term: 20-30 life of DUSEL Deep Exploration Station (DES) for drilling to great depth Outpost sites for geomicrobiology exploration and experiments Central campus Dedicated microbiology lab Surface lab and freezer storage
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Sampling minerals and bio-film surrounding a flowing borehole, December 2005
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Aspen High School, Aspen, CO Basalt High School, Basalt, CO Roaring Fork Valley High School, Carbondale, CO Lake County High School, Leadville, CO The highest-elevation school in U.S. -- 10,152 feet above sea level SALTA: Snowmass Area Large Time-Coincidence Array Empire Clear Creek High School, Empire, CO
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Polishing scintillator edges outside Conference Center Making detectors light-tight SALTA Workshop, July 2001, Snowmass, CO mass phototube gluing
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CROP Summer Workshops http://crop/unl.edu/
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CROP article in Lincoln Journal Star, 7 August 2003
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PMMA (polymethyl methacrylate) doped with a scintillating fluor 2 ft x 2 ft x ½ inch Read out by 10 stage EMI 9256 photomultiplier tube The Chicago Air Shower Array recycling retired detectors from the Chicago Air Shower Array located in the Utah Desert: 1089 stations, 15m spacing covering 0.23 square km
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U.S. Army Photo September 30, 1999 The CROP team at Chicago Air Shower Array (CASA) site
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CASA detectors’ new home at the University of Nebraska 2000 scintillator panels, 2000 PMTs, 500 low and power supplies at UNL
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Aspen Center for Physics Education & Outreach Workshop July 6-8, 2004 SALTA schools take over the library, setting up cosmic ray telescopes, for training in the new DAQcard that will be used in all their data-taking.
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A portable stand held each muon telescope. Detectors telescoped pair with coincidence requirement against noise sandwiching a ¼ inch lead sheet were configured into muon telescopes 2 modules taken down into the mine Detectors moved at 2-3 week intervals
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since dust posed a problem for a PC we housed a low-power serial digital data logger alongside the DAQcard Acumen Instruments Databridge development kit
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Desktop Base Station An ~identical pair of modules ran in a fixed location (surface office) to establish our baseline
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SALTA’s Henderson Project was launched September 29, 2004
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Clear Creek High School students set up the satellite modules at the 1 st underground location
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Basalt High School students move the detectors to their 2 nd location
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Rates at Henderson surface base station (10,337 ft above sea level) = 2.5 rates at Lincoln, NE (elevation: 1189 ft) Data collected between Sept 29 – Dec 8, 2004 monitored 4 locations between depths of 2800-3900 ft Raw rates in muon telescopes seen to drop from 10 Hz (surface rate) → 1.5 Hz → 0.5 Hz → 0.3 Hz Some preliminary observations
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Channel 0,1 coincidences Channel 2,3 coincidences SALTA high school students are now analyzing the data identifying stable data run periods bad data channels …and learning about the statistical nature of random events Students will next learn to calculate accidental coincidence rates and statistical error
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The photon is massless and has no antiparticle (is its own antiparticle) But all the fundamental particles of matter do have antiparticles: e + e ee+ee+ ++ p pp p n nn n The quark content of pions show while other mesons are their own antiparticle
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1965 Gellmann & Pais noted a 2 nd order (~rare) weak interaction could induce the strangeness-violating transition of K o a particle becoming its own antiparticle! uu s d s d KoKo KoKo WW u u s d s d KoKo KoKo WW WW KK The neutral kaon however is not its own antiparticle: KK
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u d ee e _ u u d d WW e+e+ e _ u d u d d u but have never observed: have observed: Cowan & Reines: Savannah River
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In many even-even nuclei, -decay is energetically forbidden. This leaves -decay as the allowed decay mode. 76 As 33 76 Ge 32 76 Se 34 Endpoint Energy 22 0+ 2+ 0+ Atomic mass (u) 76 Ge 32 75.921402 76 As 33 75.922393 76 Se 34 75.919913 is observed!
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If were its own antiparticle (or could oscillate into ) there could be a chance to observe neutrino-less double-beta decay events. the observed process being searched for! neutrino-less
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Energy Spectrum for the double-beta decay Summed Energy for the 2 Electrons (MeV)
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A single claimed observation has been made… but is very controversial ! 214 Bi The “internal conversion” process competes with emission producing spectral energy lines superimposed upon any continuous beta decay spectrum Q = 2039 keV predicted 76 Ge endpoint energy ?? …and needs to be independently verified! Evidence for Neutrinoless Double Beta Decay H..V. Klapdor-Kleingrothaus, A. Dietz, H.L. Harney (MPI-Kernphysik, Heidelberg, Germany), I.V. Krivosheina (Radiophysical-Research Institute, Nishnii-Novgorod, Russia) Modern Physics Letters A, Vol. 16, No. 37 (2001) 2409-2420 Heidelberg-Moscow 76Ge Detector At Gran Sasso
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CUORE - 760 kg TeO2 Major US efforts The MAJORANA expt- 500 kg Ge76 (86%) EXO - 1-ton LXe TPC
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