# B Cyclotron design question

#### Mentz114

Gold Member
I'm trying to work out what velocity and magnetic field strength one needs to capture the charged particle in a circle of comfortable lab size - say 5cm ( 0.05m).

For a sodium ion ( mass = 3.8175407 × 10-26 kg) with charge q = 1.60217653 x 10 -19 , velocity 183234 m/s, C in a magnetic field of 2 Tesla the radius of the circle $R=mv/qB$ is 0.0218m.

The velocity requires a 4000v potential and seems a bit big. Have I made an error ?

[I'm not actually building a cyclotron, just a magnetic deflector.]

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2 Tesla is a huge field. (And please, significant figures!)

#### Mentz114

Gold Member
2 Tesla is a huge field. (And please, significant figures!)
My understanding of magnetic field strength comes from this
Code:
      Smallest value shielded        10^-14 Tesla      10^-10 Gauss
Interstellar space                  10^-10 Tesla      10^-6 Gauss
Earth's magnetic field           0.00005 Tesla      0.5 Gauss
Small bar magnet                 0.01 Tesla      100 Gauss
Within a sunspot                   0.15 Tesla      1500 Gauss
Small NIB magnet                0.2 Tesla      2000 Gauss
Big electromagnet                1.5 Tesla      15,000 Gauss
Strong lab magnet                10 Tesla      100,000 Gauss
Surface of neutron star        10^8 Tesla        10^12 Gauss
Magstar                                10^10 Tesla      10^15 Gauss
and the strongest I saw in a (small) cyclotron was 9 T.

With U = 1000V, B = 0.2T one gets R = 0.109m

In the ball park ( absent errors ).

(sorry about the redundant digits )

Last edited:

"Cyclotron design question"

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