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tuning_the_s800_xdt [2023/09/22 15:15]
swartzj [CRDCs setup]
tuning_the_s800_xdt [2025/03/07 14:07] (current)
swartzj
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 This page gives the steps that are followed when tuning the S800. The two possible tuning modes are included, namely, the Focus mode and the Dispersion-matching mode. This page gives the steps that are followed when tuning the S800. The two possible tuning modes are included, namely, the Focus mode and the Dispersion-matching mode.
  
-Before proceeding, it is mandatory to complete all the steps of the [[to-do list|to-do]] list necessary to prepare the S800 for tuning. The preparation of the S800 for tuning is covered by the A1900 prior to every experiment.+Before proceeding, it is mandatory to complete all the steps of the [[to-do list|to-do]] list necessary to prepare the S800 for tuning. The preparation of the S800 for tuning is covered by the S800 group prior to every experiment.
  
  
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 ===== Unreacted beam ===== ===== Unreacted beam =====
-In the first part of the XDT, the rigidity of the S800 is typically set to match the value of the fragment beam (selected in the A1900) after passing through the S800 target. This is where the term "unreacted beam" comes from.+In the first part of the XDT, the rigidity of the S800 is typically set to match the value of the fragment beam (selected in the A2400) after passing through the S800 target. This is where the term "unreacted beam" comes from.
  
  
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 ====== Dispersion Matching Mode ====== ====== Dispersion Matching Mode ======
  
-In the dispersion-matching optics, the S800 focal point is achromatic, i.e. the position of the beam in the dispersive direction does not depend on the momentum. As a consequence, the beam is momentum-dispersed on the target area (pivot point) with a dispersion of about 10 cm/%. The main goal of the tuning is to ensure that the position and angle dispersion are cancelled at the focal plane, thus maximizing the resolution at that point. We also want a good image in the object position, which will also contribute to increase the resolution at the focal plane. +In the dispersion-matching optics, the S800 focal point is achromatic, i.e. the position of the beam in the dispersive direction does not depend on the momentum. As a consequence, the beam is momentum-dispersed on the target area (pivot point) with a dispersion of about 10 cm/%. The main goal of the tuning is to ensure that the position and angle dispersion are cancelled at the focal plane, thus maximizing the resolution at that point. We also want a good image in the object position, which will also contribute to increasing the resolution at the focal plane. 
  
-Charge-exchange experiments require typically this optics. In some cases, the beam used is <sup>3</sup>H, which has a rather high rigidity (around 4.8 Tm). This imposes a serious constrain, because the maximum rigidity of the spectrograph is 4 Tm. Thus, in this case, the tuning of the S800 is done with <sup>3</sup>He, produced with a CH2 target.+Charge-exchange experiments require typically this optics. In some cases, the beam used is <sup>3</sup>H, which has a rather high rigidity (around 4.8 Tm). This imposes a serious constraint, because the maximum rigidity of the spectrograph is 4 Tm. Thus, in this case, the tuning of the S800 is done with <sup>3</sup>He, produced with a CH2 target.
  
   * Set trigger to “s800 trigger”   * Set trigger to “s800 trigger”
tuning_the_s800_xdt.1695410151.txt.gz · Last modified: 2023/09/22 15:15 by swartzj