66Ni run 29 September-5 October 2011

Target issues
* Target number #460 UC2C-Ta surf, RILIS
* Mass markers: Ni, Rb

* No converter
* GPS separator
* Extraction electrode n/a mm (real distance)
* Uht(GPS, CCV)=30.2 kV, Uht(trap, CCV)=30.00 kV, Elec05=180 V

Yield measurements

Beam visible on FC – see below

Experimental issues
* Beam to Miniball T-REX
* IS504

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

ISOLDE
For 87Rb YGPS.FC490=77 pA (overestimated?), YGPS.FC558=45 pA, YCA0.FC68=46 pA,
XTRAP.FC10=45 pA

Stable beam

87Rb19+
Tperiod 51 ms, Tbreed 40 ms, Icoll 230 mA, 525.912 kHz, gas 7.5 V

trap inj=6.6 pA, BTS.FC20=4.0 pA, RFQ.FC20=11.5 pA, TRAP=60.6%, TRAP+EBIS=9.17%

Linac transmission and energy: 
No stripper foils. WITCH magnets 0.1 and 3T.

Transmission from RFQ.FC20 to XL65.FC50 at 2.60 MeV/u

- 80% for A/q = 4

- 77% (50-80%) for A/q = 3.882 66Ni17+

Delivered beam at 2.6 MeV/u

Total transmission (radioactive beam)
GPS.FC490_to_trap x Trap_EBIS x Linac
0.9*0.098*0.77=7%

Delivered beams

66Ni17+

Tperiod=51 ms, Tbreeding=48 ms, Icoll=230 mA

TRAP.FC10       6 pA (zero with laser off -> no background)
RFQ.FC20 (17+)  10 pA -> 9.8%

NORMGPS=>ISOGPS

For a proton current of ~1.6 uA

GPS.FC490       17 pA
RFQ.FC20        11.5 pA
L65.FC50        11.5 pA Something strange with linac transmission.

Miniball        10 pA

Setting summary
For GPS we used:

GPS_SEP_30200V_2011-09-22_87Rb.csv
GPS_CA0_RAO_30200V_2011_09_22_87Rb.csv 

REX low energy settings saved as:

110929_1158_BTS_87Rb_30000_9.1%.csv
110929_1158_TRAP_87Rb_30000_9.1%.csv
EBIS_110929_1833_GPS_66Ni17+_10%.csv

REX separator and linac settings saved as:
111003_1144_Aq3.8824_2.60MeVu_MB_WITCH on.csv
111003_1144_SEP_Aq3.8824_2.60MeVu_MB_WITCH on.csv 

Technical problems

* Change detector box an IHS RF chain.

* Preamplifier 7gap3 stopped, error VAC analog. Beam off for 8 h.

* Repeated problems with amplifier 7gap2 down for at least 2+3 hours.

* XIHS.MQ60+80 switched off due to overheating, at least twice.

* cfv-170-arextrap stopped. Didn’t prevent the beam from passing though.

* Electrostatic elements in GPS10 and 20 switched off for 3 ½ hours.

Comments / Lessons learned

* Could not tune on 39K out of ISOLDE as too high fluctuations. Used 87Rb.

* The behaviour of the RF for the cyclotron cooling is not normal. When going to the list frequency for 66Ni the beam was attenuated with a factor two compared with switching off the cooling. We also noticed that the cooling effect at 60Ni wasn't very effective.