Cu run

Target issues:

* The target from the previous Ni run on GPS broke and we had to use a UC2 target, W line, laser ioniser on the HRS.

* Target number 306, used on HRS.

* To improve the Cu/Ga ratio 6 equidistant proton pulses per supercycle.

REX issues

isotopes run: 68Cu19+, 70Cu19+ and 69Cu20+

breeding time: 98 ms, peak charge at 19+

currents:

* For 12/12 pulses, 1E13 p/p with 68Cu we had:

TRAP inj plate = 3 pA; BTS.FC20 = 2.8 pA; RFQ.FC20 >9 pA for 19+

* For 6/12, 3E13 p/p with 70Cu we had:

TRAP inj plate = 1 pA; BTS.FC20 = 0.5-0.8 pA; 2.5 pA in the peaks on RFQ.FC20 for 19+

* For 3/12, 3E13 p/p with 69Cu we had:

BTS.FC20 = 0.9 pA; 1 pA in the peaks on RFQ.FC20 for 20+

efficiency:

* HRS.FC690 to REXTRAP:~100% (can we trust the reading of ISOLDE FCs?)

* Trap >50% for stable 65Cu+ from HRS (25% trap beam gate);

* EBIS 17% for 65Cu19+ from HRS (25% trap beam gate);

* For 68Cu19+ the EBIS efficiency was >17%

* For 70Cu19+ the EBIS efficiency was >16%

* Linac Linac transmission quite poor, max. 60%

Linac energie:

* 2.83 MeV/u

comments:

* The low repetition rate (10 Hz) was imposed by duty cycle limitations in the Linac.

* Linac transmission quite poor due to running at reduced energy without preparation.

* Amplifiers worked nicely stable, 200 MHz system running at 300 us, 10 Hz, rf-power: <60kW (Design: 1ms, 100Hz, 110 kW).

technical problems:

* Miniball complained about unstable and decreasing beam intensities. Could be caused by:

Variations in the laser ionisation efficiency (difficult to monitor without GLM)

Temperature drifts of Linac timing, last bending magnet and other elements since the hall temperature varied a lot

* HRS Faraday cups not reliable; depends on if they are in open or closed mode

* Vacuum problem in ISOLDE closed some valves

* The Profibus / Wago module at the REXEBIS gun platform stopped once and the electron beam was lost. A reboot of the EBIS FEC was required.

* Main CS computer for the REXTRAP had to be rebooted once

lessons learned:

* Use a shorter time gap between the pre-trigger and the RF pulse of the Linac to reduce the sensitivity of the delay adjustment.