Sr and Ba MD run June 2007
Target issues
* UC2-C #355, Ta surface
* mass markers Sr, Ba, Ca, K
* separator setup at 30.2 kV
Yield check
ca 2-8pA stable beam seen on FC490 on mass 150. maybe
134Ba+16O ?
148Ba with p on target: 1.2e4/muC p on converter: 3.7e3/muC
96Rb with p on target: 1.2e7/muC p on converter: 5.4e6/muC
96Sr yield, much lower than 96Rb, cannot be determined because of major
contribution
from 96Rb
7 pA stable 115In / uC protons (-> difficult to tune REXTRAP so the
molecules are kept
as they are swamped by the 115In
peak)
129Ba+19F contribution not estimated
REX issues
Fluorine molecules (136Ba+19F,
88Sr+19F, 96Sr+19F) broken into REXEBIS.
Stable isotopes accelerated:
136Ba32+ (A/q=4.25
2.22 MeV/u)
period time 153 ms, no beam gate, breeding
time 120 ms (not optimized for 32+, should
be 150 ms)
Currents: Inj.plate=32pA, BTS.FC20=12pA, RFQ.FC20=21pA, L65.FC40=16 pA
Efficiency: HRS.FC490 to inj.plate=100%, Trap=37.5%, TRAP+BTS+EBIS+SEP=2%,
LINAC=76%
88Sr21+ (A/q=4.19
2.21 MeV/u)
period time 51 ms, no
beam gate, breeding
time 48 ms (not optimized for 21+)
Currents: Inj.plate=67pA, RFQ.FC20=40pA, L65.FC40=31.5pA
Efficiency: HRS.FC490 to inj.plate=100%, TRAP+BTS+EBIS+SEP=2.8%, LINAC=79%
88Sr23+
(A/q=3.83 2.21MeV/u)
period time 101 ms, no beam gate, breeding time 98 ms (not optimized for 23+, should
be 120 ms)
Currents: Inj.plate=115pA,
RFQ.FC20=40pA
Efficiency: HRS.FC490 to
inj.Plate=100%, TRAP+BTS+EBIS+SEP=3.2%
Radioactive isotopes accelerated:
96Sr23+ (A/q=4.17
2.23 MeV/u)
period time 101 ms, breeding
time 98 ms
Currents: very low, not seen on FC
Technical problems
* Trap electrode 14 still
grounded…so still bad efficiency through the TRAP.
* Not enough time to set up 9GP so max energy was limited to 2.2MeV/u.
* Some RF problems on IHS and 7GP3. Can this explain poor transmission at
higher A/q?