The Rutgers 12” Cyclotron

The Pursuit of Resonance!

Where Hydrogen gas is inserted and ionized

Where Hydrogen gas is inserted and ionized

Primary Source of Capacitance in Cyclotron

Where Hydrogen gas is inserted and ionized

Primary Source of Capacitance in Cyclotron

This is the inductor used to turn the cyclotron into an LRC circuit

Tim wound it from a refrigerator coil!

Our Problem:

•During the Cyclotron’s normal operation, its resonance frequency changes on its own

Our Problem:

•During the Cyclotron’s normal operation, its resonance frequency changes on its own

Our Solution:

•Build an adjustable capacitor plate that responds to the changing resonant frequency of the cyclotron and behaves appropriately

Implementation:Takes signal from signal generator and output of cyclotron and send it through a mixer

For our purposes, the mixer takes the two inputs and converts them to a positive or negative DC voltage depending on the phases of the inputs

Implementation:Takes signal from signal generator and output of cyclotron and send it through a mixer

Put signal through H-bridge and switch logic, which are in turn connected to…

H-Bridge Switching Logic

Implementation:Takes signal from signal generator and output of cyclotron and send it through a mixer

Put signal through H-bridge and switch logic, which are in turn connected to…

H-Bridge Switching Logic

LM 311Comparators

PNP trans.

NPN trans.

Implementation:Takes signal from signal generator and output of cyclotron and send it through a mixer

Put signal through H-bridge and switch logic, which are in turn connected to…

H-Bridge Switching LogicThe And Gates

The Switches

Implementation:Takes signal from signal generator and output of cyclotron and send it through a mixer

Put signal through H-bridge and switch logic, which are in turn connected to…an adjustable capacitor plate whose distance from the high voltage is governed by an electric motor

A second idea for the adjustable Capacitor plate

A second idea for the adjustable Capacitor plate

Pros:

Greater adjustable range of resonant frequency, around 70 kHz of play vs. 20 kHz with the single plate only

A second idea for the adjustable Capacitor plate

Pros:

Greater adjustable range of resonant frequency, around 70 kHz of play vs. 20 kHz with the single plate only

Cons:

oThe additional plate causes a shift in the cyclotron’s resonant frequency

•Turns out this doesn’t matter, so we decided to go with the second idea

•Unfortunately we were not able to get that far

Here’s a summary of how things should’ve gone:The signal applied across the cyclotron and the output of the cyclotron are compared in a device called a mixer

The mixer sends either a positive, negative, or zero DC volt signal into our H-bridge/switching logic depending on the relative phases of the two input signals

The positive or negative voltage either withdrawal or extend an adjustable capacitor plate. The response of the adjustable plate is designed to respond in a manner that automatically corrects the change in the cyclotron’s resonant frequency

After installation of the equipment and some testing, the unit is meant to be left alone, operating on the feedback of the cyclotron

Where did we get stuck?

H-Bridge Switching Logic

Anthony and I were unable to integrate the switching logic and the H-bridge

It turns out that these little devices are a pain(!!).

LM 311 Comparators

But we both sure learned a lot and enjoyed our experience!