Author/Authors :
Perrino، نويسنده , , R and Lagamba، نويسنده , , L and Cisbani، نويسنده , , E and Colilli، نويسنده , , S and Crateri، نويسنده , , R and Leo، نويسنده , , R.De and Frullani، نويسنده , , S and Garibaldi، نويسنده , , F and Giuliani، نويسنده , , F and Gricia، نويسنده , , M and Iodice، نويسنده , , Iommi، نويسنده , , R and Leone، نويسنده , , A and Lucentini، نويسنده , , M and Mostarda، نويسنده , , A and Nappi، نويسنده , , E and Pierangeli، نويسنده , , L and Santavenere، نويسنده , , F and Urciuoli، نويسنده , , G.M، نويسنده ,
Abstract :
The silica aerogel threshold Cherenkov counter for the Jefferson Lab Hall A spectrometer was tested at CERN with a mixed beam of positrons, pions, and protons in the 1–4 GeV/c momentum range. Aerogel from Airglass, Sweden, with a refractive index of 1.025 was used. For this momentum range and refractive index only positrons and pions are above the Cherenkov threshold. Detection efficiencies of 96% for pions and of 98% for positrons were measured. A 5% fake proton detection was also measured, mostly caused by induced δ-rays and accidentals generated by high counting rates.
