[PEPPo] [EXTERNAL] Re: Proposed requirements for the electron driver for the positron source

[Eric Voutier]

 Hello Alicia, Reza, 

 I cannot comment about the implication of these parameters on the design of the electron injector but perhaps more on the beam parameters 
 we would like to have when using the beam.

 1) Positron production : a reasonable beam spot size could be of the order of 1mm FWHM with small angular divergence at the production target; the energy spread is not critical as long as it is in the few percent range.

 2) Physics experiments (at LERF) : in the case of using that beam for doing physics measurements, you would certainly want small beam emittances and small energy spread i.e. a good quality beam.

 The goal would be to achieve both operations without compromising the design.

 Best, Eric

----- Mail original -----
De: "Alicia Hofler via PEPPo" <peppo at jlab.org>
À: peppo at jlab.org
Envoyé: Jeudi 9 Novembre 2023 22:05:56
Objet: [PEPPo] Proposed requirements for the electron driver for the	positron source

Hello all,

We have been asked to define the high and low limits of the gun voltage for the electron driver for the positron source.

In order to evaluate what is a "good" (good for the positron target), we are proposing to use a beam with more relaxed requirements than used for CEBAF.  The beam parameters that we prioritize for CEBAF are normalized emittance, bunchlength, and energy spread (sigma Ek).  For the positron driver, we are proposing to increase the CEBAF bounds by a factor of three.

We are asking for your comments on this proposal and for your suggestions for increasing or decreasing any of these requirements.  We plan to use these bounds for our simulation studies.

Attached is a document listing the initial and design parameters for the positron driver at LERF reported at IPAC 2023.  The document also provides the proposed increased CEBAF parameters under the title "Consider" (in the middle of the page) as well as the FEL 2004 parameters with an analogous three-fold increase for reference (at the bottom of the page).

-Alicia and Reza
-- 
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Alicia S. Hofler             JSA/TJNAF
hofler*at*jlab.org    Newport News, VA
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