Can Cosmic Rays Be Economically Used in Particle Accelerators?

[john taylor]

would it be a more economical idea to accelerate cosmic rays from the atmosphere which are already traveling at 43 percent of speed of light as particles in a particle accelerator. Do you think that this would be more economical in principle or that you could achieve higher collision speeds?

 

[Vanadium 50]

A. How do you plan to accelerate them?
B. How do you plan to know where they are going to be in order to accelerate them?
C. How do you plan to collect enough of them to make all the collisions you want?

 

[john taylor]

I don’t this is not developed i was just wondering if it was conceptually a good idea

 

[mfb]

Where does the 43% number come from? That is an oddly specific number for the large energy range of cosmic rays - most of them way above 43% the speed of light.

Accelerating a proton to 43% the speed of light needs an energy of about 0.1 GeV. The LHC accelerates protons to 6500 GeV. Even if cosmic rays would produce a nicely collimated beam (they do not) it wouldn't be worth catching it.

The highest rate of cosmic rays at the ground comes from cosmic rays muons, of the order of 1 per cm² and minute. 1 cm² is larger than a typical beam but let's use that to be optimistic. About 1 in 1000 of them are in a (very generous) suitable direction (<1 degree off). That means we get maybe one muon every 15 minutes, and that is very optimistic. Muons also decay within microseconds so we can't store and accumulate them.
The LHC accelerates bunches of 10¹¹ protons, separated by 25 ns, corresponding to a current of 4*10¹⁸ protons per second, 21 orders of magnitude more than our cosmic ray capture process.
The collision rate in a collider scales with the product of the beam currents (+some other factors I neglect here). Our cosmic ray capture muon collider would have 42 orders of magnitude disadvantage. That is a factor 1000000000000000000000000000000000000000000. We would never get even a single collision out of it.Does that mean cosmic rays are useless? No. They are always available, and sometimes they save you the effort to build an accelerator. Particle detectors need to be tested before installation, and the relative position of all their parts needs to be known as accurately as possible, ideally before starting the main physics measurements. In both cases cosmic muons are a nice tool. They are a free source of reasonably high energy particles going through the detectors.

 

[Vanadium 50]

The highest rate of cosmic rays at the ground comes from cosmic rays

True that!

I think you meant to write "comes from muons".

 

[ZapperZ]

would it be a more economical idea to accelerate cosmic rays from the atmosphere which are already traveling at 43 percent of speed of light as particles in a particle accelerator. Do you think that this would be more economical in principle or that you could achieve higher collision speeds?

I'm as puzzled as mfb. Where did this "43%" come from? Many cosmic rays are extremely relativistic particles, meaning they are practically at c.

Secondly, the purpose of high energy physics experiments are to have particle collisions which are the main purpose of the study. It isn't just getting to "high energy" that is crucial. A bunch of other factors have to also come into play, such as the interaction luminosity. Ignoring the extreme difficulties in getting the "right particle" to enter a collision section of a collider, there is the issue of how many useful and measurable collisions one can get in a reasonable amount of time! No one is going to fund a $10 billion facility that produces just a handful of collisions a year! The statistics in getting and finding what you want will just not be there.

This is a good opportunity to educate. When we design an experiment, there are often MORE than just one criteria that is required. In this thread, it appears that the energy of the particle was the only consideration. That is not the end of the story, not by far. In the design of particle accelerators, a lot of factors have to be considered, depending on what they are designed for. Particle accelerators for FELs require beam quality with very low emittance, not just high energy.

I don’t this is not developed i was just wondering if it was conceptually a good idea

Unfortunately, as Mies van der Rohe once said, god is in the details. It isn't a conceptually good idea because the idea is not well-developed for there to be any rational evaluation. When scientists come up with what we call "back-of-the-envelope" idea, there has to be something more concrete than what you have presented (i.e. what is the rate of useful particles that can be captured at such-and-such energy range). It has to have both concepts and ball-park quantitative values. It is pointless and a waste of time to come up with a pie-in-the-sky idea that isn't realistic and practical. That last part is often lost in many ideas that are offered here in this forum.

Zz.