16/03/2023
Plunger chamber closed, some dummy target and stopper probably inside
run 72 eagle closed
run 73 right half of EAGLE completely opened
Three screenshots are attached:
Run 72 EAGLE closed
1) Three rings. There is significantly more 511 in ring 143 than in 117, 101
2) 5 detectors of ring 143. They all look similar to each other.
Run 73 right half of EAGLE opened
3) 5 detectors of ring 143. The 3 detectors in the opened half hardly see 511 keV, the other 2 do.
Check with Colibri and a gamma scintillator probe ws done: largest activity is visible close to the target chamber, in the region starting at the edge of the chamber, end ending about 6 cm upstream.
About 80 gamma counts/s are seen there. The count rate decreases further upstream.
Background rate: 20 to 30 counts/s, 25 counts/s in Sala Fizykow.
Radioactivity line seen in the spectra, with the same behaviour as 511: 743.5, 936 keV, 1434 keV. These are lines from 52Cr, fed by beta+ decay of 52Mn.
Confirmed by Michain gamma-gamma.
52Mn can be produced in the a2pn channel in the reaction 32S+27Al
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