From christof.vockenhuber@triumf.ca Tue Mar 29 12:22:12 2005 Date: Tue, 29 Mar 2005 12:01:25 -0800 From: Christof Vockenhuber To: Dave Hutcheon Cc: Christof Vockenhuber Subject: Ca-40 run plan Second draft of Ca-40 run plan (March 30 to April 11) 0) condition ED1 to at least 165 kV mount new 130 ug/cm2 Mylar windows install and test IC with alphas prepare CSB with Carbon foil / SiN foil paper work (safety, beam request, technical review) Part I (March 30): 1) 40Ar2+ beam out of OLIS (RF source) 2) tuning through RFQ 3) stripping to 7+ (20Ne - 40Ar ratio) 4) tuning through DTL (1.133 MeV/u) 5) tuning to DRAGON gas target 6) transmission FC4 - FC1 with CSB out, no gas 7) CSB in -> increase in current at FC1 8) charge state distribution (scan of MD1) 9) measure beam energy after CSB 10) tune 40Ar through recoil separator (charge state 15+, ED1 ~ 150 kV or 14+, ED1 ~160 kV) 11) attenuation to a few 100 cts/sec 12) IC runs (130 ug/cm2 mylar window, 50 Torr) 13) optimize IC voltages (start point cathode -450 V, anode +150 V) for best energy resolution 14) adjust gain matching if IC sum spectrum shows shoulders or tails 15) runs at pressures 40, 50, 60 Torr, at the highest pressure 40Ar should be stopped in anode segment 2 (no signals from segment 3), record all pressures and voltages for later comparison with 40Ca beam! Part II (April 5 - 11): 1) 40Ca2+ beam out of OLIS (SI source) 2) tuning through RFQ 3) stripping to 7+ (20Ne - 40Ca ratio) 4) tuning through DTL (1.133 MeV/u) 5) tuning to DRAGON gas target 6) transmission FC4 - FC1 with CSB out, no gas 7) CSB in -> increase in current at FC1 8) charge state distribution (scan of MD1) 9) measure beam energy after CSB, adjust beam energy to value of 40Ar run 10) tune 40Ca through recoil separator (same charge state as for 40Ar, settings should be not very different) 11) attenuation to a few 100 cts/sec 12) IC runs (130 ug/cm2 mylar window, same pressure as in 40Ar runs) 13) identification of peaks: 40Ca should be lower in deltaE and higher in Erest. Maybe 40K (0.0117%) is also visible (between 40Ca and 40Ar) if only one peak visible, change pressure in IC (best separation should be at 50 Torr) 14) optimization of OLIS to increase 40Ca2+ output from OLIS: a few pnA are optimal, but we can run with a few 100 ppA 15) measure 40Ar/40Ca ratio with different attenuation (10 cts/s to 1000 cts/s) to see whether the attenuation has an influence on the 40Ar contamination 16) switch to recoils (44Ti) with CSB in and no gas: there should be no recoils visible 17) put gas in (4 Torr), adjust energy (on NewScaling page) to center beam after MD1, energy loss should be ~100 keV per Torr 18) IC run to look for recoils, rate should be 5 recoils/sec/eV/pnA 40Ca beam (omega-gamma = 8.3 eV, 30% charge state fraction, 100% transmission -> rate = 12 cts/sec), look for recoil/gamma coincidences 19) measure energy loss of recoils adjust spectrometer (energy of recoils on NewScaling page) to maximize recoil count rate 20) measure charge state distribution of beam (current at FCCH, down to 11+) and recoils (count rate at IC, down to 13+) with and without CSB, gas in (4 Torr) 21) change to charge state 12+ (use "Up to MD1" in the Advanced Scaling page), measure change of beam properties with 4 Torr gas with and without CSB (energy loss, emittance growth, beam size at charge slits) 22) optional: 40Ar run at very end of beam time, look for recoils 2nd beam time: measure excitation function around 3 strong resonances (Ex ~ 9.23 MeV/u) with small steps (2 keV/u per step).