Undergraduate and Graduate Opportunities in Nuclear Science at Simon Fraser University

Transcription

1 TRIUMF Undergraduate and Graduate Opportunities in Nuclear Science at Simon Fraser University, Jean-Claude Brodovitch, Krzysztof Starosta Department of Chemistry Simon Fraser University Burnaby, BC, Canada

2 Location UBC SFU TRIUMF

3 Simon Fraser University Arthur Erickson & Geoffrey Massey SFU (1965) has over 25,000 students and 90,000 alumni, and more than 700 tenure-track faculty

4 Department of Chemistry 27 research-active faculty Research Areas Analytical Inorganic & Bioinorganic Organic & Biological Physical and Nuclear Interdisciplinary Research Materials Science Chemical Biology

5 Department of Chemistry Minor in Nuclear Science: Profs C. Andreoiu, K. Starosta, J.C. Brodovich NUSC Introduction to Radiochemistry NUSC Introduction to Nuclear Science NUSC Nucleosynthesis and Distribution of the Elements NUSC Radiochemistry Laboratory NUSC Special Topics in Nuclear Science * CHEM Directed Study in Advanced Topics of Chemistry * NUSC Particle Physics PHYS Quantum Physics

6 35 NUSC 341 NUSC 342 NUSC 344 NUSC 346 NUSC minor awarded Enrollment Year Student enrolment in the four courses specific to the nuclear science minor program in the last 10 years. The black bars refers to the number of graduating students enrolled in the nuclear science minor program.

7 Chemistry Graduate Program Ph.D Program M.Sc. Program Application Process Coursework Tuition Fees and Financial Support Student Services Need more information?

8 Research Canada Foundation for Innovation British Columbia Knowledge and Development Fund

9 Rotations in the Universe

10 How We See Different Size Objects λ = ħ/p

11 Electromagnetic Radiation λ = ħ/p

12 Constituents of matter A Z X N? A atomic number Z protons N neutrons

13 Binding energy per nucleon Source:

14 Binding Energy Energy that is released when a nucleus is assembled from neutrons and protons m( Z, N) = Zm + Nm Bc p m p = proton mass, m n = neutron mass, m(z,n) = mass of nucleus with Z,N n 2 B = 0 for H, otherwise B > 0 2 D 1 - deterium BE = ( ) x MeV = MeV 4 He 2 BE = (2* * ) x MeV = MeV 238 U 146 BE = (92* * ) x MeV = MeV The more nucleons packed into a nucleus, the more energy is released, and thus the higher the binding energy.

15 Importance of Uranium Z = U U U Abundance % % % Half-lives 2.455E5 y 7.038E8 y 4.468E9 y Uranium is a metal, common and abundant in nature, found in most rocks, soil, rivers, oceans, food; Uranium is a unique element because of its potential to generate huge amounts of energy. Eight pellets of uranium, each smaller than an average adult thumb, contain enough energy to power an average home for about one year. 1 kg of coal makes 3 kilowatt-hours of electricity. 1 kg of oil makes 4 kilowatt-hours of electricity. 1 kg of natural gas makes 6.5 kilowatt-hours of electricity. 1 kg of natural uranium makes 60,000 kilowatt-hours of electricity. Source: Canadian Nuclear Association

16 Nuclear Landscape (Ségre Chart) What are the limits of nuclear existence? Where are the drip-lines? What is the last element we can make? How does the nuclear force depend on varying proton/neutron ratio? How to explain collective phenomena from the individual motion? Tests of the Standard Model and the fundamental conservation laws known nuclei stable nuclei proton drip line Z > 110 protons,z neutrons, N 82 unknown nuclei neutron drip line

17 Magic Numbers and Shell Model a nucleon moves in a common potential generated by all the other nucleons Maria Goeppert Mayer and Hans Jensen Nobel Prize Physics 1963 "for their discoveries concerning nuclear shell structure" M.G. Mayer, Phys. Rev. 75, 1969 (1949)

18 vibrations Vibrations octupole prolate rotor oblate rotor

19 Changes in Nuclear Structure h 9/2 f 5/2 p 1/2 p 3/2 f 7/2 h 11/2 g 7/2 d 3/2 s 1/2 d 5/2 g 9/2 Nuclear shell structure N=5 N=4 3p 2f 1h 3s 2d 1g p 1/2 f 5/2 i 13/2 p 3/2 h f 9/2 7/2 d 3/2 h s 11/2 1/2 g 7/2 d 5/2 g 9/2 As we add neutrons, traditional shell closures are changed, and may even disappear! This is THE challenge in trying to predict the structure of nuclei at the extremes of stability towards the neutron drip line. very diffuse surface neutron drip line harmonic oscillator no spin orbit around valley of stability J. Dobaczewski et al., Phys. Rev. C 53, 2809 (1996)

20 Main Astrophysical Processes How were the elements first created? Life cycle of stars and why they shine astrophysical models require a considerable amount of nuclear information as input M.S. Smith and K.E. Rehm, Ann. Rev. Nucl. Part. Sci, 51 (2001)

21 Shell Structure Affects Nucleosynthesis Shell structure in neutronrich nuclei affects the r-process path this changes the predicted abundances of r-process isotopes Need experiments to determine whether: N=82 and 126 shells are quenched or Astrophysical model is wrong abundance (per 10 6 Si) Abundance N=82 shell quenched Full N=82 shell gap mass number Mass number, A ETFSI-1 solar ETFSIQ K.L. Kratz et al. Ap. J. 403, 216 (1993); B. Pfeiffer et al., Z. Phys. A 357, 235 (1997)

22 TRIUMF Owned and operated as a joint venture by a consortium of Canadian universities via a contribution through the National Research Council Canada Canada's National Laboratory for Particle and Nuclear Physics Laboratoire national canadien pour la recherche en physique nucléaire et en physique des particules Production Accelerator TRIUMF 500 MeV Cyclotron 100 µa high-energy proton beam ISAC Isotope Separator Accelerated Beam MeV/A Thick/Hot Target Ion Source Ion Beam 60 kev DTL1 RFQ High β SCRF MeV/A Med β SCRF Low β SCRF DTL2 S C L I N A C

23 ISAC I and TRIUMF Isotope Separator and Accelerator (ISAC) Accelerated radioactive beams Energy up to 4.5 MeV/A (A~150) 15 MeV/A for light nuclei

24 High Power Targets

25 Fusion-Evaporation Reactions MeV/A yrast line lowest energy for a given angular momentum

26 TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer TRIUMF ISAC Gamma Ray Escape Suppressed Spectrometer Detects gamma rays de-populating excited states

27 Associated Detection Systems Bambino Si CD (LLNL, Rochester) SHARC (York, Colorado) Bragg Detector (York) CsI(Tl) Array (Saint Mary s) DESCANT (Guelph) DANTE (Guelph/TRIUMF) GRIFFIN (Guelph) 11 cm

28 Gamma-Ray Radiation and Nuclei γ γ γ Germanium detector Excitation energy, kev Angular momentum, ħ Number of counts E = ħ 2 I(I+1)/2I γ-ray energy, kev Cu 30 Gamma-ray energy (kev)

29 59 Cu A Nucleus as a laboratory Zn GAMMASPHERE + MICROBALL experiments 28 Si + 40 Ca 68 Ge* 59 Cu + 2α + 1p Beam energy 146 MeV; σ rel ~ 5% Cu E x ~32 MeV Ni Extensive level scheme 150 levels, 320 γ-ray transitions 8 rotational bands 5 prompt proton decays discrete γ decay-out mechanism C. Andreoiu et al., Phys. Rev. C62, (R) (2000) Eur. Phys. J A 14, 317 (2002)

30 TIGRESS integrated plunger (TIP) at SFU 186 Pb (Z = 82; N = 104) A. Andreyev at al, 2000 N = Z shape coexistence 68 Se (N = Z = 34) 72 Kr (N = Z = 36)

31 Recoil Distance Method 40 Ca Beam 36 Ar v/c ~ 0.08 µm Recoil v/c ~ 0.04 For v/c ~0.04 a 1 ps (10-12 s) lifetime corresponds to 12 µm

32 Tigress Integrated Plunger K. Starosta

33 The Tigress Integrated Plunger device implements Recoil Distance Method measurements of pico-second (10-12 s) lifetimes for gamma-ray decaying states at TIGRESS, combines a plunger apparatus for positioning of a target and a stopper with a large (3π) solid angle CsI array of charged particle detectors for channel identification in fusion-evaporation and other reactions, will be first used in an experiment investigating shape coexistence in 68 Se and in studies of shape coexistence and evolution along the N = Z line, has been funded in 2009 through a Research Tools and Instruments (RTI) grant by the National Sciences and Engineering Research Council of Canada (NSERC)

34 Delayed Gamma-Ray Spectroscopy at EMMA s Focal Plane Techniques: Aim: Set-up: Topics: recoil decay tagging technique (RDT) isomer decay tagging (IDT) delayed gamma decays depopulating isomeric states EMMA, TIGRESS large highly-efficient Ge clover detector double-sided silicon strip detectors (DSSSDs) Study of N~Z nuclei at and beyond the proton-drip line; 100 Sn and the validity of the Z = 50 shell gap Beam Prompt gamma decay, TIGRESS The Electromagnetic Mass Analyser, EMMA The SFU Clover Detector DSSDs The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again. Delayed gamma decay

35 Department of Chemistry Low radiation lab equipped with fume hood for wet radiochemistry, on top of a neutron vault; pneumatic rabbit

36 ThermoFisher Scientific P-385 neutron generator for induced-fission studies K. Starosta 10 8 neutrons/s

37 252 Cf spontaneous fission yields

38 232 Th neutron-induced fission yields 232 Th provides access to r-process nuclei around mass 80, specifically in the vicinity of N=50, Z=28 shell closure

39 Fission twin ionization chamber Provide: atomic number identification (ΔZ~1 for Z 1 /Z 2 ~45/55) atomic mass identification (ΔA~2 TKE integrated) direction of the track in space C. Budtz-Jorgensen et al. NIM A258 (1987) 209

40 Long-term plan Build a set of compact twin ionization chambers with segmented electrodes optimized for neutron-induced fission studies with a TFS P-385 neutron generator. Develop a TIG-based DAQ system. Apply Digital Signal Processing and fission fragment tracking algorithms, search for rare isotopes. Couple the chamber with an efficient γ-ray array minding the impact of the neutron flux from the generator: 8π multiplicity filter for entry distribution studies, reconfigured 8π detectors for high resolution studies, a dedicated array of high-resolution scintillators (LaBr ).

41 Proposal: E- Driver New Front End New Target Stations BL4N 500MeV Cyclotron ISAC Existing Target Stations BL4N is proposed to deliver 500MeV protons to two target stations for beam production and an additional RIB station for development Take advantage of the shielded and unused proton hall to add an electron driver to supply electrons to the new target area via a separate beamline; Develop new ISAC front end to permit three simultaneous RIB beams (two accelerated).

42 Training of Highly Qualified Personnel Postdoctoral studies, profs, etc Jobs at TRIUMF (cyclotron operator) Nordion (isotope production) BC Cancer Agency Nuclear medicine Nuclear Power Industry IT, finances/banks, etc...

43 OUTREACH ACTIVITIES AT SFU SFU open house Science in action TRIUMF tours

44 Open House at SFU - poster Radiation in Everyday Life Do not be afraid! Be Informed! Types of ionising radiation X-rays and gamma rays alpha particles beta particles neutrons Sources of Radiation Living at the Boundary of a Nuclear Station Less than 0.05 msv Medical Sources Less than 1.0 msv Natural Background 3 msv Other Sources 0.04 msv

45 Doses Typical radiation doses from natural sources (msv/year) Source Average Range Cosmic Rays to 1.0 External terrestrial Inhalation (radon) to to 10.0 Ingestion to 0.8 Total to 10 Useful Applications of Radiation Medical diagnosis and treatment Nuclear power Archeology, environment, etc Science and technology Radiation measurements Typical average radiation doses from man-made sources (msv/year) Source Average Range Medical to 1.0 Nuclear bombs Nuclear power to to 0.02 Geiger Muller detector Large scale detectors Nuclear Science Minor, Department of Chemistry, Simon Fraser University ask Dr. Andreoiu at corina_andreoiu@sfu.ca, phone

46 Kit

47 Contact Information Simon Fraser University Department of Chemistry 8888 University Drive Burnaby, BC, V5A 1S6

48 Thank you very much for your attention

49 Molecular Rotations and Vibrations (Bjerrum 1912) m1 r1 r rotation axis CM r2 m2 L= 5 L= 4 L= 3 L= 2 L= 1 L= 0 15 ħ 2 /I 10 ħ 2 /I 6 ħ 2 /I 3 ħ 2 /I 1 ħ 2 /I 0 Absorption spectrum of HCl (note the double peaking caused by two isotopes of Cl) λ = 3 µm = 3 x 10-4 cm, IR moments of inertia bond and force length

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