Optics Meeting Jun 7 2022 230PM ET

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  1. New Approach for vz reconstruction(Vassu) [1]
  2. Understanding the residual vz dependence of Asymmetry (Vassu) [2]


Bill, Vassu, Zuhal, Brynna, KK, Ciprian, Chandan, Jim, James (Stony Brook student who will begin helping with MOLLER GEM analysis), Kate


- Vassu: residual v_z dependence of asymmetry. We are now confident that the v_z dependence we saw last week was due to energy loss because the v_z dependence disappears when a gaseous hydrogen target is used instead of a liquid hydrogen target. We can use QED to deconvolute the energy loss in our reconstructed results.

- Vassu: reconstructing v_z using sieve_r and tg_th. The z vertex can be found using the r value at the sieve plane and the scattering angle theta. The variable sieve_r is highly correlated to gem_r and gem_rp, so we can use these gem variables to reconstruct sieve_r. Using the reconstructed sieve_r and tg_th, Vassu showed that he was able to estimate v_z to within a couple of mm.

  • This method will only work this way for elastic events because it's not including the energy loss in the target, but it's possible that we could add in the energy loss separately to this method.
  • Within the experiment, the scanners will allows us to exactly know the sieve hole locations, so instead of predicting the sieve_r, we could use the known location of the sieve hole in r. The method Vassu showed could be a way of checking our scanners using elastic events.

- Vassu/Kate: sieve hole placement. Vassu showed that we can find exact radial locations for which we MUST have a sieve hole using the E' vs theta moller kinematics.

  • For pass 3 we are currently unable to access the desired values of theta due to minimum constraints on our acceptance region. We need to place a sieve hole at such a small radius that the particles would not make it through the collimator 2 acceptance. We should think about ways to fix this. Is there a different target location that will gain us access to these theta values?
  • Will power deposition allow us to make the inner bore smaller? We could place a hole at a smaller radius if the inner bore were smaller too. Kate will look into power deposition for smaller inner bore radii.
  • Ciprian suggests we have one hole places such that we know some of the particles traveling through it will be blocked by coll2. This way we can confirm how much actually gets blocked.

Meeting link information

Meeting URL


Meeting ID: 972 5975 5403

Passcode: 4937

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