Expected counting rates

FRS experimental setup Total load is limited by SC1 and MUSIC1

Count rate limitations At S1 ~10 5 s -1 (SC1) At S2 ~10 4 s -1 (MUSIC1 - Munich) TPC ?

Modified LIESCHEN code Cross-sections for nuclide production in the target are read from ABRABLA output (Wojtek Gawlikowicz)

Normal setup Proposal values : – 238 U beam 950 A MeV –Pb target 1500 mg/cm² –No degrader at S1 LIESCHEN results: –Width of the x distribution at S2: 24 cm –Total counting rate at S1 and S2 is ~5×10 -3 per beam particle –Counting rate for 132 Sn is 7×10 -5 per beam particle Primary beam I max = 2×10 6 s -1 (limited by the MUSIC1) 132 Sn counting rate 140 s -1

SC-11 SC-41 SC-21 Position MUSIC-1 (Munich) Fragmentation target (Be) MUSIC-2 MW-1MW-2 Fission target Degrader Modified setup Slits Can we reduce the total counting rate without affecting the yields of 132 Sn and get possibility to increase intensity of primary beam?

Modified setup - optimization Degrader thickness so that the ratio of total counting rates at S1 and S2 becomes ~10: –10000 mg/cm² ≈ 55% of range – 132 Sn attenuation ~50% –Secondary production of 132 Sn ? Slits (-3,3)cm Target thickness: 800 mg/cm 2 –Width of the x distribution at S2: 20 cm MAXIMUM LOAD AT BOTH S1 AND S2 Primary beam I max = 2×10 7 s Sn counting rate ≥ 350 s -1 Factor of 2.5 more than in the normal setup

Comparison Normal setupModified setup Target thickness [mg/cm²] Degrader [mg/cm²]no10000 Max Primary Beam Intensity2×10 6 s -1 2×10 7 s -1 Counting Rate at S11×10 4 s -1 1×10 5 s -1 Counting Rate at S21×10 4 s -1 Counting Rate 132 Sn140 s s -1 Width of the x distribution at S2 [cm] 2420

Primary beam position, charge states Normal setup fully stripped: Pos. at S1: 15.0 cm Pos. at S2: cm one electron: Pos. at S1: 12.7 cm Pos. at S2: cm two electrons: Pos. at S1: 10.4 cm Pos. at S2: cm Modified setup fully stripped: Pos. at S1: 13.5 cm Pos. at S2: cm one electron: Pos. at S1: 11.2 cm Pos. at S2: cm two electrons: Pos. at S1: 8.9 cm Pos. at S2: cm