Who/What/Where is TRIUMF ? TRIUMF is Canada's National Lab for - - PowerPoint PPT Presentation

▶
who what where is triumf
SMART_READER_LITE
LIVE PREVIEW

Who/What/Where is TRIUMF ? TRIUMF is Canada's National Lab for - - PowerPoint PPT Presentation

Nov 11, 2022 137 likes •474 views

Who/What/Where is TRIUMF ? TRIUMF is Canada's National Lab for Particle and Nuclear Physics ~470 staff, ~220 Canadian Scientists, ~380 foreign scientists Joint venture of UBC, SFU, UVic, Alberta, Carleton, Toronto Collaborations

slide-1
SLIDE 1

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

  • TRIUMF is Canada's National Lab

for Particle and Nuclear Physics

  • ~470 staff, ~220 Canadian Scientists,

~380 foreign scientists

  • Joint venture of UBC, SFU, UVic,

Alberta, Carleton, Toronto

  • Collaborations with 14+ institutions

in Canada, 36+ abroad

  • Happen to be located on UBC

campus

Who/What/Where is TRIUMF ?

slide-2
SLIDE 2

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

  • DO ...

Stellar nuclear synthesis Fundamental Interactions Medical Physics Nuclear structure Material properties Applications of physics

What do we do ?

  • DON'T ...

Make bombs Generate power Have an assembly line

slide-3
SLIDE 3

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

WHY ?

D' ou venons nous? Que sommes nous? D' ou allons nous ?

Physicists ask - “ Why does the universe and everything in it exist, and why does it look the way it does”

slide-4
SLIDE 4

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

This Hour has 13 Billion years

1.The Standard Model (briefly)

  • 1. What is everything made of ?

2.Big Bang Cosmology (briefly-er)

  • 1. History of the universe

3.Connection between 1) and 2) 4.Creation of the elements

  • 5. (Where TRIUMF fits in)
slide-5
SLIDE 5

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

“Fundamental particles”

  • Idea of a fundamental particle age old
  • started with Democritus (~400BC)
  • “atom”

means indivisible

  • Search for the fundamental constituents of

matter, and the fundamental rules governing their interaction is called Particle Physics

  • Techniques have evolved drastically over time
slide-6
SLIDE 6

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Evolution of the “fundamental particles”

  • “fundamental”

pa rticles are electrons and quarks . . .

  • . . . which have no size
  • Huh ? Then how is stuff “

s olid”

slide-7
SLIDE 7

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Fundamental Forces

Helium

u u d d

n p

==> “ P hoton Exchange” ==> “ Glu on” Ex change ==> “ W, Z Boson” Exchange Electromagnetic Force

(also binds molecules)

Strong Force

(also binds nuclei)

Weak Force

(important for radioactive decay)

(not to scale)

Forces give matter its structure

slide-8
SLIDE 8

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

How do we “see”

p

λ = 500 nm (0.00000005 m) E = 2.5 eV λ λ = 0.000001 nm E = 500 000 000 eV

slide-9
SLIDE 9

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

  • Idea #1 : to “

see ” so mething, must “touch” it with something smaller

  • Idea #2 : in quantum mechanics,

higher energy ==> smaller dimensions

Why we build particle accelerators

slide-10
SLIDE 10

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

“particle” Energy [eV] size [µm] “what” Light ~1 ~1 cell Helium nucleus ~1 000 000 ~0.000 01

  • ther nuclei

proton ~500 000 000 ~0.000 000 000 5 protons, neutrons electron ~100 000 000 000 ~0.000 000 000 000 000 000 1 quarks

Tools of the trade

slide-11
SLIDE 11

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

The Standard Model (on a T-shirt)

slide-12
SLIDE 12

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

The “other” force - Gravity

  • Einstein's General Theory of Relativity
  • Gµν = 8π Tµν – λ gµν
  • “geometrical” theory unlike Standard Model
  • Friedmann (1922) said that GR

predicts that universe is expanding

  • Edwin Hubble (1929) observed that

universe is expanding

  • Hmmm, if universe is expanding,

if we run clock backwards, then ...

slide-13
SLIDE 13

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

The Big Bang

  • Take all the energy in the universe, and

start shrinking it into a smaller and smaller volume

  • Average energy gets higher and higher
  • (think compressing a bicycle pump)
  • Eventually energy high enough to -
  • Break apart atoms, then
  • Break apart nuclei, then
  • Break apart protons, then
  • etc etc ...
  • Eventually get to a point – The Big Bang
slide-14
SLIDE 14

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

History of the Universe, Part II

TRIUMF

slide-15
SLIDE 15

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Big Bang: the moment after

  • A “roughly-pretty-good-outline-of-an-
  • idea”

about what happened

  • t<10-43 seconds:
  • “quantum gravity” ???
  • 10-43<t<10-35 seconds:
  • As universe 'cooled', gravitation force

separated from others

  • ~10-35 seconds : Inflation !!
  • Universe enlarges unimaginably fast
  • From much smaller than a proton to the

size of a softball

slide-16
SLIDE 16

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Hot Particle Soup

  • 10-35<t<10-5 seconds
  • “somehow”

fun damental particles are created

  • Strong force separates from

the others

  • Then Weak force separates

from Electromagnetic

  • W, Z bosons created
  • “Soup”
  • f quarks, photons,

gluons, W, Z, etc...

  • Too energetic to stick together
slide-17
SLIDE 17

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Whence Antimatter ?

  • Q: if we started with equal

matter and anti-matter, why didn't they just annihilate each

  • ther and leave just photons ?
  • A: CP Violation i.e. Matter and

anti-matter interact (very) slightly differently.

  • Result in small excess of matter
  • NOT TOTALLY UNDERSTOOD
slide-18
SLIDE 18

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Primordial Nucleosynthesis

  • 10-5<t<100 seconds:
  • Most Anti-particles gone
  • Quarks+gluons slow down

enough to bind into protons, neutrons, mesons

  • But no nuclei form since

deuteron (p+n nucleus) unstable

  • 100 s < t < 300,000 years
  • Deuteron stable, light

elements form

  • But only up to 7Li since

no stable mass-8 nuclei

  • p, D, 3He, 4He, 7Li
slide-19
SLIDE 19

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Cosmic Background Radiation

  • At 300,000 years, nuclei capture

electrons to become atoms

  • T=3000K
  • Universe now transparent to photons
  • As universe expands, photon

wavelength increases

  • Energy decreases
  • Expanding blob of gas
  • Almost all hydrogen
  • Not exactly uniformly distributed
  • Slight density differences
slide-20
SLIDE 20

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

STOP !!!Are you pulling my leg ?

  • Predict that if T~3000K @

13 billion years go THEN ~3K today

  • Measurement - bang on !
  • Inflation predicts universe smooth

and flat

  • tiny CMB deviations --> smooth
  • Also distribution of galaxies
  • Pattern of deviations --> flat
  • General relativity calculation
slide-21
SLIDE 21

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Are you pulling my leg ? (part 2)

  • W, Z bosons observed by

experiments at CERN, SLAC

  • A TRIUMF experiment helped

determine key property of W

  • CP violation detected in 1964
  • matter/anti-matter asymmetry
  • TRIUMF helped build detector for

latest-generation experiment studying this problem

  • Predicted BBN element abundances agree

with observation

  • And CMB pattern supports the result
slide-22
SLIDE 22

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

What happened next ? The Stars formed

  • After ~1 billion years, inhomogeneities

in gas clouds 'clump together' by mutual gravitation to common centre

  • Eventually, speed up enough to initiate

nuclear fusion reactions

  • Reaction primarily creates more helium

from the hydrogen

  • Clusters, galaxies, etc. forming as well
slide-23
SLIDE 23

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Red Giant phase

  • Helium gradually builds up in core
  • Eventually Helium core contracts, outer

expands --> Red Giant

  • Energy increases so that Helium can

fuse to make Carbon and Oxygen

4He + 4He → 8Be 4He + 8Be → 12C (carbon) 4He + 12C → 16O (oxygen)

slide-24
SLIDE 24

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Heavier element synthesis

  • For stars < 10 solar masses
  • process stops at oxygen
  • Becomes nebula+white dwarf
  • H, He, C, and O ejected into space
  • Star > 10 solar masses
  • Enough energy for helium, carbon,
  • xygen, and silicon fusion
  • Process stops with iron production
  • Iron most tightly bound nucleus
  • Get onion-like structure in star
slide-25
SLIDE 25

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Stellar burning time scales

1 day 6 months 600 years 5 x 105 years 7 x 106 years Duration

  • f stage

3 Billion Cobalt, Iron, Nickel Silicon 1 Billion Magnesium, Sulfur, Phosphorous, Silicon Oxygen 600 Million Oxygen, Neon, Sodium, Magnesium Carbon 100 Million Carbon, Oxygen Helium 4 Million Helium Hydrogen Threshold Temperature (K) Major Products Fuel

slide-26
SLIDE 26

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Heavy Element Synthesis - supernova

  • Stars > 10 solar masses
  • No more fusion after iron produced
  • No more energy to counteract

gravitational collapse

  • In seconds, major implosion

followed by explosion – supernova !

  • Heaviest elements created
  • “R-process” , “s-process”
slide-27
SLIDE 27

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

What happens to ejected matter ?

  • Matter ejected from nebula or

supernova eventually recombine from gravitation attraction to form new stars

  • Hydrogen, etc tends to collect in centre
  • New star !
  • Heavier elements tend to the edges
  • Planets !
  • Densest elements end up in ... men ?
  • We are Star Dust !
slide-28
SLIDE 28

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Are you SURE ?? - Yes.

  • Look at the solar surface, interstellar

space to determine relative abundances

  • Model stellar evolution and see if you

can predict it

  • Study meteorite grains older than solar

system

  • RESULT ? - very good agreement
slide-29
SLIDE 29

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Nuclear Astrophysics at TRIUMF

  • Agreement NOT perfect, still

much to learn

  • TRIUMF ISAC facility studies

these stellar reactions

  • Nuclear astrophysics
  • Premiere facility in the world
slide-30
SLIDE 30

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

13 billion years later . . .

slide-31
SLIDE 31

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

Summary

  • Historically parallel pursuits of particle physics and cosmology

have now converged

  • This is an extremely exciting time for these fields
  • New accelerators and astronomical devices promise great discoveries
  • Getting closer to age-old question . . .
  • Answer ? We are star dust.
  • (In our own quiet way, TRIUMF is playing a key role)

D' ou venons nous? Que sommes nous? D' ou allons nous ?

slide-32
SLIDE 32

Marcello M. Pavan, TRIUMF, Sechelt Oct 27, 2006

“Beyond” the Standard Model

  • Standard Model incomplete
  • What about Gravity ???
  • Why so many particles ?
  • Neutrinos have MASS !
  • Building next generation

accelerator to test new ideas

  • Push back closer to Big Bang
  • “extra”

di mensions

  • “branes” and “

s uperstrings”

  • TRIUMF taking part in the fun