E-rhic-ir-l mailing list

["Berg, J Scott" <jsberg AT bnl.gov>]

The fractional energy uncertainty is (beta*gamma)^2 times the fractional path length uncertainty, assuming our RF frequency uncertainty is zero. So if I have a 1 mm path length uncertainty, that corresponds to a 2.2% energy uncertainty at 275 GeV. 1 mm doesn't sound unreasonable to me, especially considering what we are doing with the off-axis orbit.

 

-Scott

 

From: E-rhic-ir-l <e-rhic-ir-l-bounces AT lists.bnl.gov> On Behalf Of Willeke, Ferdinand via E-rhic-ir-l
Sent: Monday, February 22, 2021 10:03 AM
To: Aschenauer, Elke <elke AT bnl.gov>; e-rhic-ir-l AT lists.bnl.gov
Subject: Re: [E-rhic-ir-l] IR to do list

 

Elke, the storage rings are huge spectrometer systems. We know the beam energy to the extent we know the absolute strength of the dipole magnets.

(this could be determined to 1E-4 for a single reference magnet together with 1E-4 relative precision referring to the reference magnet for all magnets.)

We also must include orbit data and corrector strength in the analysis.

What is the precision, the experiment needs?

You might remember that one can use spin depolarizing resonances for higher precision for the electron beam (done for the exact mass of the Y in Doris and SPEARS).

Ferdinand

 

From: E-rhic-ir-l <e-rhic-ir-l-bounces AT lists.bnl.gov> On Behalf Of Aschenauer Elke-Caroline via E-rhic-ir-l
Sent: Monday, February 22, 2021 9:40 AM
To: E-rhic-ir-l AT lists.bnl.gov
Subject: [E-rhic-ir-l] IR to do list

 

Good Morning,

 

I thought the discussion on Friday was very good and it would make sense to generate a "to do list” accessible for everybody 

and document how a specific item has been resolved.

 

I have been thinking a bit more about the points over the weekend and actually I have one more for the list we talked about the uncertainty on the overall beam energy, this will be very important for the  physics as we rely on knowing the beam energy.

 

The other item I think we need to make a decision is that we really do as discussed on friday the solenoid compensation scheme without introducing vertical kicks at the IP.

 

Thanks elke

 

 

 

 

 

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