JYFLTRAP: Spectroscopy with multi-trap facility

• Facility• Mass purified beams• In-trap spectroscopy• Future plans

JYFLTRAP Layout

RFQ-cooler/buncher

Penning traps

Spectroscopy set-up

IGISOL beam

Spectroscopy with purified beams

RFQ cooler buncher and purification trapMRP 20 000 ... 150 000 Cycle time down to 100 ms Total transmission ~ 10 % Maximum intensity tens of thousands/bunch

Example A=112Coming experiments: Ga, Zr

Frequency scan over cyclotron frequencies of 112Ru and 112Rh, ions are detected with MCP. Mass difference is about 4 MeV. Cycle time 450 ms. MRP = 72 000.

Example A=112 fission products

4 MeV

Total trap cycle 450 ms340 ms cooling15 ms dipole excitation f=1705 Hz/160 mV90 ms quadrupole excitation fc=960190 Hz/150 mV

-gated -spectrum collected in one hour.112Rh and 112Ru were produced in proton induced fission.

Test results A=112

959900 960000 960100 960200 960300

0

5

10

15

20

25

30

Mo

PdAg

Tc

Rh

Ion

s a

.u.

Frequency (Hz)

Ru

Mass resolving power

A=112 fission products

Simulated frequency scans over fission products with different MRP

MRP = 70 000 MRP = 30 000

Experiments along N=Z line

1734600 1734700 1734800 1734900 1735000 1735100 1735200 1735300

0

2000

4000

6000

8000

10000

12000

14000

ZnCu

Ions

a.u

.

Frequency (Hz)

64Zn(p,x)

A=62

Ga

MRP = 20 000

Example 62Ga (t½=116ms)

From old IGISOL 400 ions/s (reaction 64Zn(p,3n)62Ga, Ep= 48MeV, Ip=35A)2-10 ions/s purified beam with present transmissionMRP 20 000 is enough to separate 62Zn and 62Cu from 62Ga

Simulated frequency scan

Improving the trap extraction

Cut one long electrode in the end of magnet region into two to squeeze the ion trajectories at the point where magnetic field lines start to diverge.

SIMION simulations for mass A=100 q=+1 ions

2.5 m

30 mm

Problematic place in extraction. Ions follow magnetic field lines.

Second einzel lens added to improve transmission to the spectroscopy setup.

Present geometry

Planned improvement

Implantation point

Challenges

Transmission through the trap system (5 - 20 %)

Cooler transmission has been poor since last summer (only ~30%)

Install Si detectors to improve diagnostics

Extraction from the magnetic field; ions tend to follow field lines

Divide one electrode

Shorter cycles (less than 100 ms)

Find limit for Ions per bunch; space charge limit

In-trap spectroscopy

• Trapped ions form an ideal source without any scattering or energy loss in source material.

• Lineshape

• Peak-to-background ratio

• Strong magnetic field of a penning trap can be used to transport charged particles (e, p, ) to the detector with high efficiency.

• Conversion electrons tr ~ 50%

• Energy and mass selection with trajectory radius rtr

• In average electron rtr< proton rtr

• Conversion electron rtr < beta rtr

Detector: Canberra RD EB10GC-500P Thickness 500 m Active area 10 mm2 (r = 1.78mm)Dead layer 250 ÅPA1201 Pre ampResolution less than 1 keV for 59.5 keV X-ray from 241Am source and 1.52 keV for electrons from 131Ba source

In-trap detector set-up

Source ions trapped in the purification trap.

Source to detector distance ~60cm.

Simulated transport efficiency ~50% up to 300keV.

In-trap plans

Near future

• Selecting a good test case, good yield, t½, electron energy, conversion coefficient

• Trap scheduling • Beamtime for testing• First physics proposal: neutron rich Zr decay spectroscopy

Open questions

• How to tune the trap injection when the ejection side is blocked by the detector ?

• How to arrange data acquisition because detector sits on HV platform ?

Later

• Segmented detector to avoid summing and allow coincidence detection

Outlook and conclusions

Purified beams

JYFLTRAP is ready to make purified beams for spectroscopyMass resolving power is enough for most of the casesTransmission needs still improvingSystematic tests of the high intensity limit together with short cycle time

In-trap spectroscopy

Mechanical parts are readyData acquisition not yet designedFirst test hopefully during next summer

IGISOL facility

IGISOL upgrade is almost ready. Improved yields have been recorded with light-ion ion guide.

Laser ion source project has been started to improve ion guide efficiency and also to introduce chemical selectivity.