26Alm experiment at Yale

Since all of the proton decays that we see are L=0, there's nothing to prevent us from putting the spectrometer at non-zero angles. The disadvantage is that each strip must be treated separately instead of adding strips of the same theta from different detectors together, and this in itself might be enough to require that the spectrometer be at zero degrees...but here's what happens if it isn't:

Ingredients:
30 MeV p beam.
Energy loss and straggling of proton beam and proton decay through a 100 μg/cm² metallic ²⁸Si target.
Tag on d to isolate decays from an 8.5 MeV level in ²⁷Si to the ground, metastable, and second excited states of ²⁶Al.
YLSA in the standard position (assuming all five sectors working!).
Energy loss and straggling of protons through dead layer of YLSA; also assume that YLSA has a resolution of 15 keV for protons.

Results:
Energy (average; error bars represent standard deviation) of protons in each individual strip of YLSA for a spectrometer angle of 0'... (click on a picture for a bigger version)



...and 10'


I was afraid that somehow the spectrometer angle would lead to a blurring of the individual decays' lines, making them harder to resolve; but as long as the strips are treated separately, there should be no problem with resolution.

Comments?