A time dilation device, generating a field radius of .16 light years, was created by the Asgard as a means to contain the Replicators. Constructed within a very old structure on the Asgard planet Hala, the device was encased in a solid neutronium shell and set with a time delay sufficient to evacuate the entire Asgard civilization before calling forth all the Replicators to the planet where they would be trapped. The device was designed to create a bubble in space within which time would be slowed by a factor of 104, in order to buy time to devise a way to eliminate the Replicators entirely. One year within the bubble would equal 10,000 years outside it, and an hour would equal more than a year. However, before the device was activated, the Replicators rebuilt the control interface mechanism and reversed it instead to accelerate time by a factor of 102, allowing them time to evolve into human form.
SG-1 used the Prometheus to journey to Hala in order to repair the device that had been altered by the Replicators. They took advantage of Fifth's humanity and his cooperation to reconfigure, reset, and reactivate the device, and Hala and the Replicators became trapped within the time dilation bubble.
The time dilation device had been only a temporary measure, expected to successfully hold the Replicators for approximately two years before they would reach the device and reprogram it. A more permanent solution was devised when the Asgard artificially collapsed Hala's sun to create a black hole that would draw in the entire planet. However, a large number of Replicators managed to come together in a coherent mass before reaching the event horizon, and, using the time dilation device to counteract the gravitational effect that should have been drawing them in, they escaped from the black hole.
A time dilation device was also offered to the SGC by Kvasir to assist in the plan to seal the subspace rupture that had allowed SG teams from alternate universes to enter our reality. The time dilation generator and a warhead were taken aboard the Prometheus on the mission to the location of the singularity, however the mission was eventually aborted when an alternate means of sealing the rupture was discovered.
Asgard time dilation technology was also part of the Asgard computer core that was installed onboard the Odyssey. When the Odyssey came under attack by the Ori, Carter activated the technology to prevent the ship's destruction. For 50 years, the team remained trapped in a time dilation bubble until they discovered a way to use the energy of the weapons blast to reverse time and undo history.
Cross Reference: Asgard, Black Hole, Fifth, First, Hala, Neutronium, Prometheus, Replicators, Thor, Time Dilation Bubble
Episode Reference: Unnatural Selection, New Order, Ripple Effect, Unending