How is the Dating of Samples of Cosmic Objects Performed, Including Pre-Solar Dust? In the new Space.com article 7 billion-year-old stardust is oldest material found on Earth I had read about some pre-solar grains dating back to 7 billion years. What techniques are used in calculating age of these grains?
Are they collected first and then radiocarbon-dating is applied? If not, what other techniques might have been used?

Scientists recently identified the oldest material on Earth: stardust that's 7 billion years old, tucked away in a massive, rocky meteorite that struck our planet half a century ago.
This ancient interstellar dust, made of presolar grains (dust grains that predate our sun), was belched into the universe by dying stars during the final stages of their lives. Some of that dust eventually hitched a ride to Earth on an asteroid that produced the Murchison meteorite, a massive, 220-lb. (100 kilograms) rock that fell on Sept. 28, 1969, near Murchison, Victoria, in Australia.
New analysis of dozens of presolar grains from the Murchison meteorite revealed a range of ages, from about 4 million years older than our sun — which formed 4.6 billion years ago — up to 3 billion years older than our sun, researchers reported in a new study.
The BBC article pointed out by @uhoh in a comment answers the question nicely. 


  To work out how old the grains were, the researchers measured how long
  they had been exposed to cosmic rays in space. These rays are
  high-energy particles that travel through our galaxy and penetrate
  solid matter.
  
  Some of these rays interact with the matter they encounter and
  form new elements. The longer they are exposed, the more of these
  elements form. The researchers used a particular form (isotope) of the
  element neon - Ne-21 - to date the grains.
  
  "I compare this with putting out a bucket in a rainstorm. Assuming the
  rainfall is constant, the amount of water that accumulates in the
  bucket tells you how long it was exposed," said Dr Heck.
  
  Measuring how many of the new elements are present tells scientists
  how long the grain was exposed to cosmic rays. This in turn informs
  them how old it is.
  
  Some of the pre-solar grains turned out to be the oldest ever
  discovered.
  
  Based on how many cosmic rays had interacted with the grains, most had
  to be 4.6-4.9 billion years old. For comparison, the Sun is 4.6
  billion years old and the Earth is 4.5 billion.
  
  However, the oldest yielded a date of around 7.5 billion years old.