🚀 go-pugleaf

In article <8400007@trsvax>, pauls@trsvax.tandy.com writes...
> 
>AnotherSSC question:
> 
>1) How many magnets are used?

Thousands of long (17-meter) dipoles and thousands of focussing quadrapoles.
A smaller number (many hundreds?) of correcting magnets (sexapoles), and of
course two monster solenoids for the two big detectors, and a variety of
specialty magnets such as final-focus magnets and extractors.  

> 
>2) In relative terms, how do they compare to other magnets in use today?
> 

They are very high field (roughly 6 Tesla), very uniform and very large.
Nothing like them has ever been built before.

>3) What is MBTF of a magnet today (FermiLab)?
> 

Don't know the specs of the Tevatron magnets. Sorry.

>4) How many 'up days' (up hours??) does the average collider have today?
> 

Now there's a loaded question if I ever heard one.  It very much depends on the
specific machine.  CERN, for example, has a reputation (well deserved) for
excellence.  When the SPS MCR (main control room) tells you that you will get 
beam at 9 am on April 6, then you don't have it at 8:59, and you will have it
by 9:01.  U.S. machines are often not so good.  I have never had a run at the
Bevalac with the machine actually running more than 50% of the promised time.
Magnets trip off, power supplies blow up, control electronics fail,
safety-interlocks trip at random, power generators fail, etc. The AGS 
(Brookhaven) has similar problems especially in the warmer months when
everything starts to overheat.  These are complicated machines, and are 
difficult to keep running.  In the end you get the beam you need, but it's
always an adventure.

In addition to down-time during your supposed beam-time on-target, the typical
machine has a maintainance schedule (one day a week down for repairs, for
example), and machine development time which can be large blocks of time, such
as weeks or months.  The Bevalac shuts down for a few months every summer,
partly because of the cost of electricity in the summer months, but also to do
needed repair.  In addition, a few days every couple a weeks are scheduled 
for routine testing of new beam-tunes, etc.  

I don't remember exactly, but the Bevalac has something like 2500 hours of
scheduled running each year.  Roughly half of that is for medical treatment of
cancer patients and others.  The rest goes to nuclear science experiments.
At more modern machines such as the Tevatron, almost all of the beam-time
will go to the high-energy experimentalists.

>5) If a SSC magnet goes fubar, is the whole thing down?

Yup.  Bummer.  But the magnets will be very reliable according to the experts.

-Scott