Why is Helium gas and nitrogen used in gene gun? What is the difference between the two?

The density of both is relatively small, the density of helium is 0.1786g / L, and the nitrogen is 1.251 g / L, both of which are suitable for gene gun.

The difference between the two:

1. Nitrogen is more economical

2. Nitrogen is easier to obtain and lower in cost.

3. Nitrogen can be obtained in the laboratory. In the laboratory, nitrogen can be obtained by mixing ammonium chloride with sodium nitrite, pure air by hot copper powder or copper mesh to deoxidize.

Although the density of helium is smaller and lighter than that of nitrogen; the filling gas used for the gene gun is better, but the process of obtaining helium is more complicated and the cost is higher.