107,109Sn run September 2009

Target issues
* Target number #411 LaC, W surface, RILIS
* Beam on target (no converter)
* Mass markers: Cs, Sn
* GPS separator
* Extraction electrode 45 mm
* Uht(GPS,CCV)=30.21 kV, Uht(HRS, HT_target)=30.2398 kV, Uht(trap)=30.00kV, Elec05=170 V

* Yield measurements by target group: 107Sn: 3.3e5/uC, 109Sn: ~2e7/uC

Experimental issues
* Beam to Miniball
* IS459

Tuning
* Normal extraction from EBIS
* REXTRAP timing free-running relative to protons pulses

ISOLDE
133Cs: GPS.WG475 slit in, GPS.FC490=850pA, CA0.FC68=800pA, Inj.plate=730pA => 86%

Low energy
Stable beam 114Sn
Tperiod=82ms, Tbeamgate=open, Tbreeding=79ms, Icoll=193mA
Trap inj. plate=16pA, RFQ.FC20(27+)=32pA
Trap+EBIS efficiency=7.4%

Radioactive beam 109Sn26+, 107Sn26+
Tperiod=82ms, Tbeamgate=open, Tbreeding=59ms (meant to be running with 27+)
Trap inj. plate=30pA, RFQ.FC20(26+)=95pA
Trap+EBIS efficiency=12.2%

Linac transmission and energy: 
74% RFQ.FC20 to XL65.FC50 for 109Sn26+, 2.85 MeV/u

Total transmission (radioactive beam)
GPS_to_trap x Trap_EBIS x Linac x MB
0.86*0.12*0.74*0.85?=6.6%

Delivered beams
* 109Sn26+, laser on/off gave 95% Sn, 5% In
4/18 pulses at 2.1E13 ppp, delay 5 s open 14 s => 8.4E6/s at secondary target

* 107Sn26+, ratio Sn/In=35/65 with beam gate, ? ratio Sn/In=25/75 no beam gate ?

For 1.6 uA proton current: 0.5-1.5 pA on trap inj plate; RFQ.FC20=2.1-2.3 pA, XL65.FC50=1.7 pA

RFQ current growing to 6 pA even with GPS.WG470 slit in.

Setting summary
For GPS we used:
* GPS-SEP-09-09-09-30200V.CSV

* GPS_REX_9-09-15_30200V.csv

REX settings saved as:
* REX-30kV-2009-09-15_GPS_109Sn.xml

* BTS-30kV-2009-09-15_GPS_109Sn.xml

* EBIS_2009-09-15_GPS_109Sn_normalextraction.csv

* 090915_SEP_Aq4.192308_109Sn26+.csv

* 090915_Aq4.192308_109Sn26+.csv

Technical problems

* When setting up the beam injection into REXTRAP the GPS target had to be increased to 30.21 kV and Elec05 lowered to 160 V. The reason could have been a large injection angle.
* Otherwise no problems encountered during the run

Comments / Lessons learned
* The GPS.WG470 slits cut the beam with 50%, thus running with them out for 107Sn
* Extremely high yield for 109Sn in the beginning when an auto-ionizing state was used. Thus the yield measurement and the Miniball yield are inconsistent. As this laser configuration depleted the dye very quickly an alternative scheme was used for the latter half of the run.