For this project we studied briefly the effects of an electrostatic field imposed upon a polarized particle. We designed an electrical device that allowed us to have a voltage difference of appoximatly 30kV between our cathod/anode. This difference of voltage (noted as “V” in the calculations), is found between an anode and a cathoded at a given distance (noted “d”).

From our limited “understanding” of Townsend discharges realised that we will need to create an electrostatic field sufficiently intense to accelerate the composition of air ( N2, O2, CO, Ar…) over our cathode/anode distance with enough final kinetic energy where the “ion/ion” or “ion/electron” or “ion/atom” collision would ionize.

We can simplify this system and consider the acceleration of a single particle in an electric field:

• Since:

E =ΔV/d where E is the electric field

• We know that:

ma=qE where “q” is the particle charge and “m” &“a” are the mass & acceleration of a given particle

• therefore:

v = V*q*T / d*m where “v” is the velocity of the charged particle & T is the time in seconds

• solving for T:

T=sqrt(2d²*m/q*V)

• Finally:

v= sqrt(2V*q/m)

This means that kinetic energy of the particle: Ec= qV

Ec must be higher than that of the ionization energy Ei in order to ionize. This energy must also be high enough to incite at least 2 ionizations in order to trigger a “townsend cascade”. We have looked at the ionisation energies of multiple elements and decided that we would like most to study the ionisation of nitrogen as it is inert and relatively safe. The down sides are that atomic N does not exist in nature and we will have to procede with N2. This choice also allows us to build the machine using nothing but “air” and the change to pure N2 will actually be an improvement on the system as Oxygen (21% of the air) requires more energy to ionize. Logistically, we also have relatively easy access to liquid nitrogen of which we hope to create a nitrogen rich environment.

This graph shows us the relatively high ionisation energy of Nitrogen.

More accurately the Ei/mol of nitrogen are:

1st: 1402.3 kJ/mol 2nd: 2856.0 kJ/mol 3rd: 4578.1 kJ/mol 4rd: 7475.O kJ/mol

-Calculate the voltage (energy) required to ionise 1 partcile

We now have two different generators:

We are still studying the relation of amperage/voltage required to ionize a given volume(mass) of air/nitrogen. We currently understand that a high voltage is required to ionize a gas. However we observed that a more powerful generator

To create a HV voltage probe for this project we simply applied the classic “Voltage Divider” :

Where we used: Our Resistors (R1 & R2) were specialised High Voltage Resistors We selected the MOX-2-12 series as they resisted up to 20kV

Since our volt-meter only is reliable upto 2kV on its own, we needed to divide our input power by a factor of 10 to be able to read 20kV of our generator.

The values chosen were 100Mohm for R1 & 10Mohm for R2

-add photo of setup-

R2 was then placed in parallel with the standard lab Multi-metre which we measure to have had an impedance of approximatly 13Mohm (we can call it R3).

Placed in Parallel with the Multi-meter: R2'= R2*R3/R2+R3 = 5.65Mohm

Finally we have an output voltage of: V(out)=V(in)*(R2'/R2'+R1)

V(out)= V(in) *0.053

where V(out) < 2kV Therefore, we have built a very basic high-voltage probe that can measure up to 37.7kV which surpasses our initial design goal.

-add margin of error-