Transcript Artificial Transmutation

Artificial Transmutation
Mr. Shields
Regents Chemistry
U02 L04
Induced (or artificial) Transformation …
The process of striking nuclei with high energy particles in
order to create (I.e change them into) new elements
AN ALCHEMISTS DREAM !
Converting Lead into Gold
Early History
1919 Rutherford performs the first induced transformation
in a laboratory
Slams an alpha particle into a nitrogen nucleus and
creates oxygen!
4
2He +
14
17 O + 1 p
N

7
8
1
Remember this reaction?
It’s how Rutherford discovered the Proton
+
Early History
This New Zealand stamp recognizes the world's first
successful alchemist who converted nitrogen atoms
into oxygen atoms.
Induced vs. Natural
-INDUCED TRANSMUTATION is not the same as Natural
Radioactivity (or NATURAL TRANSMUTATION)
-In Natural Transmutation a nucleus spontaneously decays
into another nucleus by emitting one of several particles
- INDUCED TRANSMUTATIONS require one particle to be
slammed into another to induce the change
Atom Smashers
- Induced transformations reactions require hi velocity
particles to overcome the repulsion of the charged particle
or nucleus
Nuc+
P+
- These Transmutations were originally achieved in LINEAR
Accelerators like the one at Stanford (SLAC)
2 miles long
The first type of
Accelerator built
Lower range of collision
energies achieved
Atom Smashers
CIRCULAR Accelerators like the one at FERMI Lab are
typically used in ATOM Smashing
- Used to explore what is inside neutrons and protons
- Energies greatly exceed Linear accelerators
- High energy electrostatic & magnetic fields accelerate
CHARGED particles which then slams into the target
- Particles typically approach the speed of light
Fermi Lab
Fermilab in Illinois stretches almost 10 square miles.
The Tevatron is the world’s highest energy atom smasher
Worlds largest
Hi energy particle
Collider (built in 1983)
Can produce
Particle Energies
Of 2 trillion EV
4 miles in circumference
Booster ring
Transuranium elements
Since Rutherford, Scientists have made hundreds of new
isotopes AND new elements
- All elements above atomic no. 92 are called
TRANSURANIUM ELEMENTS
- All transuranium elements are MAN MADE in atom
smashers using induced transmutation
1.
- 1940: First element above atomic no. 92 are made
238
92U
+ 10n ——> 23992U + gamma ray
beta
239
92U ——>
239
93Np
(2.36 days)
Transuranium elements
- 1950: Elements through atomic no. 98 (Cf; Californium)
242
96Cm
+ 42He ——> 24598Cf (45 min) + 10n
- 1960: Elements through atomic no. 102 (No: Nobelium)
248
96Cm
+ 126C ——> 256102No (3.3 sec) + 410n
-1998: Highest atomic number synthesized
to date is Atomic Number 118
(As yet unnamed)
Problems:
So we can use nuclear eqs. To determine what radioIsotope should be created if we know the other
Particles. Try this …

Write the nuclear equation for the bombardment
of Calcium – 40 with a positron, forcing the
emission of an alpha particle as one of the
products.
40Ca
20
+
0e
+1

36K
19
+
4He
2