each portal has 100 channels just like wifi, controlled by temperature. Each channel has 8 directions, when a particle goes in it goes in the channel from the direction it came. For each direction, there are 80 slots, so that's 640 particles per channel. If you have 100 portals all on different channels, there can be a maximum of 64000 particles. But for just 1 channel, only 640.
It also may be hard to get the particles to go in the channels and fill up every direction.
Also, for PRTO, it comes out the opposite direction/side it went in, +/- 1 direction for randomness
You can use the property edit tool. Select temp from the drop down box, and put in your temperature in kelvin. e.g. 273 degree's Kelvin is 0 degree's C.
Also for convenience: 324 Kelvin is 50 degrees C, hence 424 is 150 degrees C and so forth