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[Opal] RE: normalized emittance OPAL

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  • From: "Haj Tahar, Malek" <mhajtahar AT>
  • To: "opal AT" <opal AT>
  • Subject: [Opal] RE: normalized emittance OPAL
  • Date: Thu, 10 Sep 2015 01:37:09 +0000
  • Accept-language: en-US
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I believe that the answer lies in the definition of the trace space emittance.
I found a nice paper comparing the development of the normalized emittance and the normalized trace space emittance.

Best regards,


From: Haj Tahar, Malek
Sent: Wednesday, September 09, 2015 2:11 PM
To: opal AT
Subject: normalized emittance OPAL

Dear all,

I have little experience with OPAL and I would like to know if anyone has already encountered this problem: I track a KV beam distribution in an injection line and compute the x-rms emittance which is expected to be constant (since this is a KV beam). Instead, I obtain a strange behavior: when space charge is off, the x-normalized emittance is constant, however, once space charge is on, I have an overshoot in certain locations, specifically at the entrance and exit of some quadrupoles (attached).

I wonder if anyone has an experience with this problem.

Thank you in advance for your help!

Malek Haj Tahar UJF/BNL
PhD student / ADS-R Group

Brookhaven National Laboratory
Collider Accelerator Department
35 Lawrence Drive, Bldg. 911B, Off. 211
11973 UPTON, NY, USA

Phone: +1 (631)-344-5573
Email: mhajtahar AT

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