What kinds of transitions produce x rays
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What kinds of transitions produce x-rays?. An x-ray tube:. motor rotates tungsten to prevent over- heating. X-rays are produced 2 ways in an x-ray tube:. x-rays. Electron from cathode knocks an inner e- out, and an outer e - falls down to the empty orbital, emitting an x-ray.

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What kinds of transitions produce x-rays?

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What kinds of transitions produce x-rays?


An x-ray

tube:

motor rotates

tungsten to

prevent over-

heating


X-rays are produced 2 ways in an x-ray tube:

x-rays

  • Electron from

  • cathode knocks

  • an inner e- out,

  • and an outer e-

  • falls down to the

  • empty orbital,

  • emitting an x-ray.

2. Electron ricochets

around nucleus.

As it decelerates,

x-rays are emitted.


CAT (or CT) scans – Computed Axial Tomography

As the x-ray source

and detector rotate,

a 3-D picture is built up

x-ray

detector

x-ray

source

As the patient moves through, many slices are taken….


getting a CAT scan…

brain CT scans


The idea behind particle accelerators (atom smashers):

________ particles

+ high __________:

old

energy

_______ particles because

________

new

E = mc2

The more the ________________ given to the old particles,

the more _________________ of the new ones by E = ______.

energy

the mass

mc2


Ex: Early particle accelerators

used _______________ generators:

van derGraff

voltage V

  • high _______________

  • work done on

    a charge q:

    W=

  • high _______________

  • work done on

    a charge q:

    W =

qV

Ex: How much KE will a proton gain when it is

accelerated through a potential difference of 300,000 V?

= DKE

W = qV

v ~ 7.6 x 106 m/s

crosses the Earth

in 1.7 s, but still

only 2.5% of c

W =

(1 e)(300,000 V)

W =

300,000 eV


Ex: An example of a modern particle accelerator is

the_____________________ .

cyclotron.

v

v

v

The _______________ field accelerates the particle.

The ______________ field is ____________________ to v, so it

only causes the particle to ___________________________ .

electric

magnetic

perpendicular

turn in a circle


the very

first cyclotron

world’s biggest

cyclotron

a 1939 cyclotron


The particle accelerator

at Cornell University

accelerator

storage ring

for positrons


SLAC – The Stanford Linear Accelerator Center


Fermilab in Chicago – another accelerator

built in the shape of a circle.


Find the ladder for scale.

…inside Fermilab


One of the largest – at CERN - Angels and Demons


A detector at CERN

led to the discovery

of the W and Z

particles – carriers of

the weak force


As accelerators with higher and higher _____________ were built, particles with bigger and bigger ____________were discovered.

energy

masses

There seemed to be no _____________

to the________________ of newly

discovered particles.

pattern

hundreds

_____________________

_____________________

tracks of subatomic

particles

Finally, the _________________________ was worked out in

the _______________ . It explained how all of the particles

are made of ________________ fundamental particles and

their _________________________ .


Decay of a K+ meson in a bubble chamber:


cloud chambers: use

supersaturated gases


Bubble chamber:

1 Fill a large cylinder with a liquid heated to just below its boiling point.

2. As particles enter the chamber,

a piston suddenly decreases its

pressure, and the liquid becomes

superheated.

3. Charged particles create an

ionization track, around which

the liquid vaporizes, forming

microscopic bubbles.


Ye

Olde

Bubble

Chamber

from

Fermilab

(Chicago)


bubble chamber tracks


As accelerators with higher and higher _____________ were built, particles with bigger and bigger ____________were discovered.

energy

masses

There seemed to be no _____________

to the________________ of newly

discovered particles.

pattern

hundreds

_____________________

_____________________

tracks of subatomic

particles

Standard Model

Finally, the _________________________ was worked out in

the _______________ . It explained how all of the particles

are made of ________________ fundamental particles and

their _________________________ .

1960s

twelve

antiparticles


_______

_______

The Standard Model: All matter (or antimatter) is

made up of ___________or combinations of____________.

leptons

quarks

  • Other 12’s:

  • a dozen

  • Jupiter’s period

  • months in year

  • hours in day

  • inches in foot

  • disciples

  • yrs. of youth

  • teenage elves

quarks

leptons

Let’s look

at leptons first.

read the fine print

__________________


increasing____________________

only found at

high energies

(high temps.)

everyday

low-energy

leptons

mass/energy

Neutrinos

have _______

_____ mass.

almost

no

  • Lepton means________________________

  • Leptons all have charge _______or__________________

  • Their antiparticles are charged __________________

  • They occur____________________—they do not

  • ___________________________________________.

“light weight.”

-1e

0 (neutral).

+1e or 0.

by themselves

combine to form bigger particles


increasing __________________

only found at

high energies

(high temps.)

everyday,

low-energy

quarks

mass/energy

  • Quarks all have charge _________or ___________

  • Their antiparticles are charged _________ or_________

  • They ___________________by themselves because you

  • cannot have a particle with a_________________________.

  • They occur in groups of _____________________

(-1/3)e.

(+2/3)e

(+1/3)e

(-2/3)e

never occur

non-integer charge

2’s or 3’s.


q

q

q

q

q

particles

made from

___________

quarks

“mes-”

means

_________

masses

“bary-”

means

_______

masses

middle

heavy

qqq

Must be all

__________ or

all_____________

or

matter

antimatter


Ex. A certain particle is made up of

3 quarks: 2 ________ quarks and

1 _____________ quark.

u

d

u

up

down

What is the total charge of the particle?

Add up the charges:

u:

(+2/3) e

u:

(+2/3) e

[(+2/3) + (+2/3) + (-1/3)] e

d:

(-1/3) e

= 1 e

Is this a baryon, a meson or a lepton?

3 quarks  a baryon

proton.

This particle is also known as a________________


d

d

Ex. A certain particle is made up of 2

quarks: 1 ____ quark and 1 __________

quark.

u

antidown

up

What is the total charge of the particle?

Add up the charges:

(+2/3) e

u:

[(+2/3) + (+1/3)] e

:

(+1/3) e

= 1 e

Is this a baryon, a meson or a lepton?

2 quarks  a meson

p+ (positive pion).

This particle is also known as a ______________________


Ex. A certain particle is made up of

3 quarks: 1 _____ quark and 2 ________

quarks.

d

up

down

d

u

What is the total charge of the particle?

u:

(+2/3) e

Add up the charges:

d:

(-1/3) e

[(+2/3) + (-1/3) + (-1/3)] e

d:

(-1/3) e

= 0 e

Is this a baryon, a meson or a lepton?

3 quarks  a baryon

neutron.

This particle is also known as a_____________________


Ex. A certain particle is made up of

3 quarks: 2 ________________ quarks

and 1 _________________ quark.

u

u

u

u

d

d

d :

u :

u :

u

u

u

u

u

u

d

d

d

antiup

antidown

What is the total charge of the particle?

(-2/3) e

Add up the charges:

[(-2/3) + (-2/3) + (+1/3)] e

(-2/3) e

= -1 e

(+1/3) e

u

u

Compare this one: to:

d

antiproton

The left-hand particle is an _______________________ . It is

an example of ___________________ . It has the __________

mass as the proton, but the _________________ charge.

same

antimatter

opposite


s

s

u

u

u

b

d

d

d

Determine the charge and type of each particle.

a whole number of e's

The total charge must be ____________________________


What is matter made up of?

neutron or

a proton


Forces

The Fundamental __________________ of Nature:


Ex: How can gravity hold Earth to the Sun if it is the

weakest force?

  • Earth and Sun have a lot of ______________

  • Earth and Sun are _________________ , so the

  • __________________________ force is not important.

  • 3. Earth and Sun are_______________ , so the

  • ________________________ forces are not important.

mass.

neutral

electromagnetic

far apart

two nuclear

Ex: The total amount of mass-energy in the universe

is:

ordinary matter: ______% (baryons and leptons)

dark matter: ______% (unknown)

dark energy: ______% (unknown)

5

23

72


Total after

Conservation Laws:

Total before =________________

Charge q

1. _____________________ is always conserved.

q1 + q2 + …

q1’ + q2’ + …

=

momentum (p)

  • In the absence of_______________ , ________________

  • is always conserved.

friction

=

p1’ + p2’ + …

p1 + p2 + …

3. In the absence of________________, ________________

is always conserved.

energy (E)

friction

Modern physics:

Classical physics:

ET ET’

mass-E mass’-E’

=

=

=

using E = mc2

KE + PE KE’ + PE’


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