# Presentation: 886346

## What does a physicist do?

- Physicists try to figure out and use the mathematical “rules” that describe the universe:

- People have been trying to do this since the dawn of history, but modern physics started in the 1680’s, when Isaac Newton figured out that the complex motion of the planets could all be figured out from a few simple equations.

- Some things physicists think about:
- Why do particles have the mass they do?
- Why is the universe mostly matter and not antimatter?
- How can we get useful energy from nuclear fusion?
- How can we put more information on a disk (or “Why DVD blue?”)?

## What do particle physicists do?

- Particle physicists use high energy particles to study things far to small to be seen any other way
- Find the smallest particles
- Find the rules for how these particles behave
- Recreate conditions as they were right after the Big Bang
- The first “particle physics experiment” told Ernest Rutherford the structure of the atom (1911)

- Study the way radioactive particles “scatter” off of atoms

## What do accelerator physicists do?

- Accelerator physicists design, build, and operate the machines that accelerate particles to high energies for use in:
- Particle physics
- Medicine:
- Cancer treatment
- Medical isotope production
- Materials science and biophysics
- Study detailed structure of materials, cells, proteins, etc, using
- Electrons
- Protons
- Neutrons
- Photons
- Industrial applications
- Electron welding
- Food sterilization
- Etc, etc, etc

## Evolution of accelerators

- The first “accelerators” were natural radioactive elements

- The first man-made accelerators would fit on a table

- Berkley “cyclotron” (1930)

## Things keep getting bigger

- 60” cyclotron (1935)
- Berkeley and elsewhere

- Fermilab
- Built ~1970
- Upgraded ~1985
- Most powerful accelerator in the world

## The Fermilab Accelerators

## Fermilab Detectors: Seeing what comes out

**CDF**

**DZero**

## Analysis: What does it all mean?

**Tape Robot**** **

## OK, but what do you do?

- Physicists usually do many different things over the course of their careers.  A few of the things I’ve spent a lot of time in the past are:
- (Fermilab, in grad school) Measuring photons to study the structure of protons
- Involved building electronics and measuring liquid Argon purity.
- (CERN, Geneva, Switzerland) Measuring how quarks are produced when electrons and positrons (anti-electrons) hit each other.
- Also worked on a software “fix” for some problems with the detector.
- (Princeton University, USA) Taught physics
- (SLAC, Palo Alto, CA, USA) Studying what happens when a really powerful laser hits an electron beam:
- In 1995, we measured something first predicted in 1935
- I worked on the “readout” for an electron detector and designed a precision particle tracker.
- (KEK, Japan) Measured the difference between matter and antimatter:
- Helped design, test and build one part of a large detector
- Also worked on a system to count bubbles to measure gas flow

## Things I’m working on now

- New system for putting beam into a very old accelerator:
- Calculated required magnet quality and did magnetic measurements
- Tried to estimate how much good this will do us.
- Working on experiment to see if one type of neutrino turns into another:

## What it takes to be a physicist

- Physicists must:
- Be curious about how things work
- Like math (and be good at it!)
- Education
- Bachelor’s degree (usually in Physics)
- PhD in Physics
- Takes about six years
- Two years of classes
- About four years doing research and writing thesis
- Physics students are usually supported by the University during graduate school
- Tuition is paid for
- Small monthly living expenses
- Career
- After PhD, the physicist will get an entry level “postdoc” position with a lab or university for 2-4 years
- After that their “real” career begins
- Lab
- Industry
- University

## Other careers at Fermilab

- About 2000 people work at Fermilab
- 500 physicists of one sort or another
- The rest are
- Engineers (mechanical, electrical, etc)
- Computer professionals
- Technicians
- Skilled trades (electricians, ironworkers, etc)
- Business and financial support
- Administrative support
- ...

## For more information

- Fermilab website
- http://www.fnal.gov
- Lederman Science Center
- At Pine St. entrance
- Email me:
- prebys@fnal.gov