Particle-system spawns like creating a "glowworm"...

Hi, i want to create a kind of glowworm in which this objects simple fades in and out. I have tested it with the particle-system but i dont know how to position the spawns on one and the same position. It emits randomly around, not the same place. How can i limit the radius of the spawn-particles? Can someone help me, please?

(MinSize & MaxSize 2, Min&MaxEnergy 3, Min&MaxEmission 0.5,The world, local, and Rnd-velocity values are 0.)

If you're using the Ellipsoid Particle Emitter (which is the default kind), you can adjust the size of the Ellipsoid within which particles are created. Select your particle system in the hierarchy, then look at the "Ellpsoid" setting. It's a drop-down setting, and when you unfold it, it reaveals the X, Y and Z size of the Ellipsoid. If you set all these to zero, all the particles will be emitted at exactly the same spot.