Louvain la Neuve
Belgium

Université catholique de Louvain
Institut Interuniversitaire des Sciences Nucléaires
Centre de Ressources du Cyclotron

 

Nuclear Astrophysics and Nuclear Structure of Exotic Light Nuclei with RNB's
In the site above you will find the recent research activities of the Louvain-la-Neuve group in the fields of Nuclear Astrophysics and Nuclear Structure

Radioactive Ion Beams

You can find here more information on the following topics :

Radioactive Beams currently available at CYCLONE

The different available charge states with their respective typical measured intensities after acceleration and separation and energy range are given.
Note that the listed beams and charge states do not represent the limitations at our facility but show what has actually been produced and measured.
 
Element
Half live,T1/2
charge state
beam intensity
[pps on target]
energy range
[MeV]
6Helium 
0.8 s
1+4
 2+4
9·106
 3·105
5.3 - 184
 30 - 734
7Beryllium
53 days
1+4
 2+4
2·107
 4·106
5.3 - 12.94
 25 - 624
10Carbon
19.3 s
1+4
2+4
2·105
 1·104
5.6 - 114
 24 - 44 4
11Carbon 
20 min
1+
1·107
6.2 - 10
13Nitrogen 
10 min
1+4
 2+4
 3+4
4·108
 3·108
 1·108
7.3 - 8.54
11 - 344
 45 - 704
15Oxygen 
2 min
2+4
6·107
10 - 294
18Fluorine
NO LONGUER
AVAILABLE
110 min
2+4
5·106
11 - 24
18Neon
1.7 s
2+4
3+4
6·106
 4·106
11 - 2444
24 - 33,45 - 55
19Neon 
17 s
2+4
3+4
4+4
 6+4
2·109
1.5·109
8·108
3·107
11 - 234
23 - 35,45 - 504
60 - 934
171
35Argon 
1.8 s
3+4
 5+4
2·106
 1·105
20 - 284
50 - 794

Background and Description of the RIB Project

The Radioactive Ion Beam Project at Louvain-la-Neuve started in 1987 as a collaboration between three Belgian universities: the Université Catholique de Louvain (UCL), the Univerisité Libre de Bruxelles (ULB) and the Katholieke Universiteit Leuven (KULeuven). These three universities joined in an "Inter-University Attraction Pole" , a government-funded science initiative. The project aimed at the production of an intense, energetic radioactive ion beam by coupling the two cyclotrons of Louvain-la-Neuve. In 1989 the first 13N beam was accelerated.  Since then the project has come a long way to the current variety of beams and numerous scientific experiments were and are being performed.
 

Technical Details on the Production of Radioactive Ion Beams

At Louvain-la-Neuve we use the two-accelerator method to produce and post-accelerate radioactive ion beams. The first cyclotron, CYCLONE 30, which is a 30 MeV proton accelerator is used to produce the desired unstable element in suitable targets. Beam intensity up to 300 µA (depending on target and desired charge state) is used to irradiate the production target.

This resulting activity diffuses out of the hot target and is fed into the ECR ion source for ionization. The used source is a 6.4 GHz designed to produce low charge states but with a high efficiency. After a first magnetic separation in a low mass resolution dipole, the ions are injected in the second cyclotron, CYCLONE 110, for subsequent acceleration up to the desired energy.

To remove any isobaric contamination from the beam, the cyclotron is tuned as a radiofrequency mass spectrometer. This is done by reducing the acceleration voltage in order to increase the number of turns in the machine . This allows the separation of beams with relative mass difference of 2· 10 -4(e.g.. 19Ne and 19 F ). This method results in an isobaric suppression factor of 10 -6 while maintaining a transmission through the cyclotron (acceleration and separation) of 3 to 5%.

In order to increase transmission efficiency for low energy beams (range of nuclear astrophysics is between 0.1 and 1 MeV/nucleon) a new cyclotron (CYCLONE 44) has been constructed but it is no longuer in operation.
 
 

Facts and Statistics of the LLN RIB Project (updated January 2007)

Below is a graph which represents the use of different Radioactive Ion Beams at our facility from 1989 to end of 2005. In 15 years, an averaged of 736 hours per year have been used for RIB. At the end of 2005 the CRC has post-accelerated radioactive beams for the equivalent of more than one full year and 3 months of continuous beamtime. In addition to these post-accelerated radioactive beams an additional 477 hours of 37 Ar was produced at the ion source extraction voltage (10-20 kV) for implantation purposes. The first beam (13N) was accelerated in 1989. In 1991 the first 19Ne beam was used followed by 35 Ar and 11C in 1993, 6He and 18 F in 1994, 18 Ne in 1996, 15O in 1997, 7Be in 1998, 10C in 2002. 2002 saw also for the first time a production of 8 different RIB's in one year, of which 6 were used for experiments and 2 for development. Moreover, 2 of the beams were post-accelerated with CYCLONE 44.

 

The total amount of time (hours) used for each beam is given in the table below

Beam
6He
13N 
19Ne 18Ne
7Be
18F
  11C
  15O
  10C
35Ar* Total
Hours
3734 
2238 
2485 1595 1034
 486
226
365
175
24 12362

* For development only.

Selected References

General

D. Darquennes et al., Phys. Rev. C42 (1990) R804
P. Van Duppen et al., Nucl. Phys. A553 (1993) 837c
M. Loiselet et al., Proc. of the 3th International Conference on Radioactive Nuclear Beams, Michigan State University, East Lansing, Michigan, USA, May 1993
M. Huyse et al., Nucl. Phys. A588 (1995) 313c
M. Loiselet et al., Production and Acceleration of Radioactive Beams at Louvain-la-Neuve 14th International Conference on Cyclotrons and their Application, Cape Town,  South Africa, 1995, World Scientific, p629,1996

Targets

The 13C target

D. Darquennes et al., Nucl. Instr. and Meth. B47 (1990) 311
P. Decrock et al., Nucl. Instr. and Meth. B70 (1992) 182

Target development

M.Gaelens et al.,  High Efficiency Release Targets for Radioactive Ion Beams : A Different Approach
Conference on Applications of Accelerators in Research and Industry (CAARI98), Denton, Texas, USA, 1998, AIP CP475, p302, 1999
M. Gaelens et al., Nucl. Instr. and Meth. B126 (1997) 125

18F production

M. Cogneau et al., Nucl. Instr. and Meth. A420 (1999) 489
M. Gaelens et al., Rev. Sci. Instrum. 67 (1996) 1347
R. Coszach et al., Phys. Lett. B353 (1995) 184

The ECR ion source

M. Gaelens et al., Rev. Sci. Instrum. V73 No.2 (2002)
C. Barué et al., Rev. Sci. Instrum. V69 No. 2 (1998)
M. Gaelens et al., Proc. of the 11th International Workshop on ECR ion sources. Groningen, The Netherlands, May 1993
P. Decrock et al., Nucl. Instr. and Meth. B58 (1991) 252
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Last updated: 1 February 2007