1. JYFL
ION COOLER
AND
BUNCHER

2. The JYFL IGISOL facility
High Voltage
Cyclotron beam
Ion guide
Separator magnet
Beam switchyard
Ion Beam Cooler
90 bend
High Voltage
Penning Trap 1
2 m

3. Cooler layout Ion beam cooler Central beam line Cooler beam line
Beam switchyard

4. 89Y

5. Energy spread Collinear laser spectroscopy setup Off-line Barium beam
dEFWHM < 4 eV 20 MHz doppler broadening
Beam intensity cut off vs. bias voltage.
Intensive beams (129Xe, few nA) dEFWHM = 1.5 eV
On-line beams 105 ions/s dEFWHM = 0.7 eV
Off-line 129Xe+

6. Delay time IGISOL delay time ~ms
Without axial field: diffusion, space charge
Depends on:
- Einj
- dEinj
- pHe
Without axial field up to hundreds of ms
Shorter by axial electric field (down to ms region)
Longer  beam bunching

8. ii
iii iv i

10. Transmission - 29 MeV proton induced fission of 238U
- Normal ion guide pressure 250 mbar
- Skimmer voltage varied
- A = 112 IGISOL beam (mostly 112Rh)
- Beta count rate in two Si-detector setups, before and after the cooler
- Transmission > 60 %

11. Bunching - Separator beam on t = 0 - 1000 msZ
+2 V
+1 V
+0.5 V
-1V
+70 V (collect)
0 V (release)
Potential along z - axis
- Separator beam on t = ms
- Cooler end plate voltage down t = ms

12. Delayed Ion-photon coincidence method
LCR
LASER
IONS
Delayed Ion-photon coincidence method
Bunched beam method
Photons gated on
the ion bunch
Counts
Singles photons
Photons gated on
the ion bunch
Ion Beam Energy Tuning (eV)

13. Bunch width - Mass and Space charge effects
174Hf
ttrap = 0.5 s
Gate1 = 15 ms
Gate1 = 30 ms
Gate1 = 75 ms
Hf (1) ms
Ti (1) ms
(with < ions/bunch)

14. Ion survival in the Buncher

15. On-line photon efficiency in collinear
laser spectroscopy (ion survival)
Without the buncher
- Metastable population
- IGISOL pressure
P. Campbell et al. Hypf. Int. 127 (2000)
With the buncher
- Off-line efficiencies hold metastables reduced
- No IGISOL pressure effects (below fig. pIG=450 mbar)