nature of Beta and Alpha particles

alpha particle:
nature - fast-moving Helium nucleus
charge - +2e
mass(atomic mass unit) - 4u
speed - ~0.1c (where c=speed of light)
energy - the same for a given source
range in air - several cm
penetrating power - stopped by paper or skin
ionizing power - strong, produce 10^3 to 10^4 ions in air per mm
effect to E&M field - bent slightly

beta particle:
nature - fast-moving electrons
charge - -e
mass(atomic mass unit) - 1/1840 u
speed - ~0.3c (where c=speed of light)
energy - depend on source
range in air - up to a meter
penetrating power - stopped by several mm of aluminum
ionizing power - weak, producing about 100 of ions in air per mm
effect to E&M field - bent strongly

indeed vacuum some how means "nothing"
so the particles can freely travel in vacuum
their motion will remain a stright line unless there are electric field or magnetic field appear