- Email: [email protected]
Accelerator facilities for pure and applied physics at Legnaro Italian Nuclear Physics National Lab
Nuclear Physics A 834 (2010) 713c–716c www.elsevier.com/locate/nuclphysa
Accelerator facilities for pure and applied physics at Legnaro Italian Nuclear Physics National Lab G. Puglierina
∗
a
INFN Laboratori Nazionali di Legnaro, Viale dell’Universita’ 2, I-35020 Legnaro (Padova), Italy The Legnaro Lab of the Italian Institute of Nuclear Physics hosts a set of accelerators for advanced nuclear physics studies as well as for various nuclear physics applications. The first Van de Graaff accelerators have been followed by the new ones based on RF superconductive cavities and high intensity normal and superconductive RFQ. The new projects move on the same line: new physics and new applications. 1. The present
The Legnaro Laboratories of the Italian Institute of Nuclear Physics (INFN) are recognized as a large scale facility at European level. The main activity for more than forty years has been the study of the properties of the nuclei and their interactions. For these studies the Lab disposes at this moment of a Tandem XTU, a superconductive Linac ALPI and, quite recently, PIAVE a new superconductive RFQ injector for the Linac. The Tandem (16 MV voltage) can operate in stand alone mode or as injector of the superconductive Linac. ALPI consists of an array of 70 superconductive quarter wave resonators, accelerating beams from C to U at energies around the Coulomb barrier. The low β section of ALPI is equipped with bulk Nb cavities while sputtered Nb on Cu QWRs are installed in the high and medium β sections. The use of Nb allows accelerating fields higher than 4.4 MV/m and a total equivalent voltage for the Linac of about 50 MV. To overcome the limitations imposed by the Tandem as an injector for the Linac, in order to produce beams of heavier masses and larger intensity, the positive injector PIAVE was developed. It consists of an ECR ion source, two superconductive RFQs (with a mass over charge state ratio A/q=8,5) and eight superconductive QWRs. The combined operation of PIAVE and ALPI can provide beams up to 100 pnA for most ions, the limit at the moment is the authorization limit of the current on target. Finally, to complete the list of the available machines in the Lab, two Van de Graaff accelerators, of 2 and 7 MV respectively, are maintained in operation mainly for interdisciplinary studies. Both machines are equipped with high quality instrumentations, in particular two microbeams are available for radiobiology studies, radiation damage and material science. Forefront instrumentation is available also in connection with the big accelerators for nuclear physics research. The two 4π charged particle detectors 8π LP and GARFIELD are mainly used for nuclear ∗
email: [email protected]
0375-9474/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.nuclphysa.2010.01.129
714c
G. Puglierin / Nuclear Physics A 834 (2010) 713c–716c
reaction studies, while the two mass spectrometers RMS and PRISMA, equipped with high resolution gamma detectors, allow precise nuclear structure studies. At this moment the Lab is involved in the commissioning of the demonstrator of the new European high resolution gamma-ray detector AGATA. The high segmentation of the instrument provides a good spatial resolution in addition to good energy measurement. Up to now two clusters of the detector have been installed and are ready to start the first exploitation of the detector for physics studies. AGATA will operate in connection with PRISMA and the total number of clusters to be installed at Legnaro will be five. 2. The future The program of the INFN for the Legnaro Laboratories in the next years is the development of SPES, a facility for RIB production in order to perform Radioactive Nuclei studies at the forefront of the nuclear physics. The idea is to benefit the two accelerators PIAVE and ALPI, as post accelerators for the selected radioactive beam, as well as the whole instrumentation available at the Lab. For the beam production many schemes have been elaborated. The ISOL method has been chosen for the production. In the first Technical Design Report it was studied that a facility based on a high intensity proton beam of 5 mA and 100 MeV, able to produce a fission rate as high as 1013 fission/s on an UCx target by two steps method i.e. converting the protons into neutrons and inducing the fission by neutrons. The project was thought to be a good prototype for the future EURISOL project too. Extensive R&D activity was developed for the different parts of the Linac, the neutron converter and the target. A proton source of 50 mA was developed at LNS (Catania) and sent to LNL. For this project at Legnaro the construction of a high intensity RFQ, able to accelerate the proton beam up to 5 MeV energy, is still under way. Extensive studies on the neutron converter and on the UCx target were performed with the support of Russian Labs and in collaboration with Ganil Lab. This activity is continuing in order to provide a neutron converter for the Ganil project SPIRAL2, while for the RIB production at Legnaro a different scheme was elaborated and presented at the last road-map discussion of the INFN. The new project is based on the consideration that the process of RIB production is much more efficient if the proton beam hits directly the UCx target in comparison with the two steps process. The problem of power deposited in the target was addressed. Optimizing the target design resulted in that it was possible to reach 1013 fissions/s in UCx target using a proton beam of 40-50 MeV and 200μA current. The UCx target is made of 7 slides, each one 1mm thick and 4cm in diameter opportunely mounted inside a high power target container. At this point the requested proton beam can be provided by a Cyclotron. A commercial Cyclotron with the requested characteristics is actually under commissioning at Nantes in France for the study of new radioisotopes. It can deliver two independent proton beams at the same time allowing the operation of two targets with a total intensity of 750 μA at a maximum energy of 70 MeV. A Cyclotron of this type is well suited for SPES: one line can provide the proton beam for the RIB production, the other one of 500 μA can have different applications like the radioisotope production as it is done at Nantes. The radioactive beams, which can become available with the new SPES version, have been evaluated extrapolating the data of the Oak Ridge RIB facility and are reported in Table 1.
66-76
72-79
72-84
75-84
86-94
89-96
90-97
111-118
110-120
115-124
116-128
123-134
124-135
129-138
134-144
139-146
141-145
Cu
Zn
Ga
Ge
Rb
Sr
Y
Pd
Ag
Cd
In
Sn
Sb
Te
Cs
Ba
La
10
+6
10
+8
10
+9
10
+7
10
+8
10
+9
10
85
3
15
15
10
10+8 +8
14
65
3
20
5
7
10+8
10
+7
10
+7
10
+8
10
+9
10
+7
10
+6
10
+6
10+6
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
SIS+LIS
SIS+LIS
SIS
LIS
LIS
LIS
SIS+LIS
LIS
LIS
LIS
LIS
SIS+LIS
SIS
LIS
LIS
LIS
LIS
Table 1: SPES Expected neutron rich beams Most Intense isotope (1/s) Ionization Eff (%) Target Ionization method 10+6 6 UCx LIS
LIS = Laser Ionization Source, SIS = Surface Ionization Source
Mass 65-69
Element Ni
***
***
*
****
***
**
**
**
**
****
****
***
*
***
**
**
**
R&D (difficulty) **
G. Puglierin / Nuclear Physics A 834 (2010) 713c–716c
715c
716c
G. Puglierin / Nuclear Physics A 834 (2010) 713c–716c
A proposal has been prepared also for the production of radioisotopes of interest for medical use: a possible list is reported in Table 2.
Table 2 Radionuclide production cross sections Radionu Target Reaction nat Cu-64 Ni Ni(p,n)
p-ener (MeV) 40
σM ax (mbarn) 50
Ni
64
Ni(p,n)
15
675
ZnO
68
Zn(p,2p)
70
25
Ga
69
Ga(p,2n)
45
100
Ga
69
Ga(p,2n)
20
550
RbCl
nat
Rb(p,4n)
50
100
Te
nat
Te(p,n)
53
150
*I-124
Te
124
Te(p,n)
12
590
*Re-186
W
W(p,n)
10
17
*Pd-103
Rh
103
Rh(p,n)
10
500
Th
232
Th(p,X)
70
60
Th
232
Th(p,X)
60
3
Th
232
Th(p,3n)
30
260
*Cu-64 Cu-67 Ge-68 *Ge-68 Sr-82 I-124
Th-228 Ac-225 *Pa-230
The proton energy that gives the largest cross-sections in the range 40-70 MeV (marked with *) has been considered.
On the same line to benefit the nuclear physics’ instruments development in order to provide opportunities in other fields, the program on the high intensity RFQ was focused on the completion of the accelerator, to realize a neutron source suitable for many applications, as the Boron Neutron Capture Therapy, which up to now has been realized with neutrons from a nuclear reactor. With this therapy it is possible to cure some tumors, the convenience of using a neutron source produced by an accelerator instead of a reactor is in the simplicity of the operations, cost and safety. With a neutron source other applications are possible as material science studies, radiation hardness and cross section measurements of interest for astrophysics or for the next generation of nuclear reactors. On the energy side, based on the experience in the construction of the high intensity RFQ, the Lab has taken the responsibility of the construction of the high intensity RFQ for the IFMIF project. IFMIF is the new machine, under construction by an international collaboration to study the material behaviours at neutron fluence rates similar to that present in the future fusion reactors. The RFQ is foreseen to accelerate a deuteron beam of 125 mA up to 5 MeV, with losses less than few per-cent. Acquiring experience with high intensity beam and the related problems may become very useful for future projects in high energy physics, in nuclear physics as well as in energy problems.
Accelerator facilities for pure and applied physics at Legnaro Italian Nuclear Physics National Lab G. Puglierina
∗
a
INFN Laboratori Nazionali di Legnaro, Viale dell’Universita’ 2, I-35020 Legnaro (Padova), Italy The Legnaro Lab of the Italian Institute of Nuclear Physics hosts a set of accelerators for advanced nuclear physics studies as well as for various nuclear physics applications. The first Van de Graaff accelerators have been followed by the new ones based on RF superconductive cavities and high intensity normal and superconductive RFQ. The new projects move on the same line: new physics and new applications. 1. The present
The Legnaro Laboratories of the Italian Institute of Nuclear Physics (INFN) are recognized as a large scale facility at European level. The main activity for more than forty years has been the study of the properties of the nuclei and their interactions. For these studies the Lab disposes at this moment of a Tandem XTU, a superconductive Linac ALPI and, quite recently, PIAVE a new superconductive RFQ injector for the Linac. The Tandem (16 MV voltage) can operate in stand alone mode or as injector of the superconductive Linac. ALPI consists of an array of 70 superconductive quarter wave resonators, accelerating beams from C to U at energies around the Coulomb barrier. The low β section of ALPI is equipped with bulk Nb cavities while sputtered Nb on Cu QWRs are installed in the high and medium β sections. The use of Nb allows accelerating fields higher than 4.4 MV/m and a total equivalent voltage for the Linac of about 50 MV. To overcome the limitations imposed by the Tandem as an injector for the Linac, in order to produce beams of heavier masses and larger intensity, the positive injector PIAVE was developed. It consists of an ECR ion source, two superconductive RFQs (with a mass over charge state ratio A/q=8,5) and eight superconductive QWRs. The combined operation of PIAVE and ALPI can provide beams up to 100 pnA for most ions, the limit at the moment is the authorization limit of the current on target. Finally, to complete the list of the available machines in the Lab, two Van de Graaff accelerators, of 2 and 7 MV respectively, are maintained in operation mainly for interdisciplinary studies. Both machines are equipped with high quality instrumentations, in particular two microbeams are available for radiobiology studies, radiation damage and material science. Forefront instrumentation is available also in connection with the big accelerators for nuclear physics research. The two 4π charged particle detectors 8π LP and GARFIELD are mainly used for nuclear ∗
email: [email protected]
0375-9474/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.nuclphysa.2010.01.129
714c
G. Puglierin / Nuclear Physics A 834 (2010) 713c–716c
reaction studies, while the two mass spectrometers RMS and PRISMA, equipped with high resolution gamma detectors, allow precise nuclear structure studies. At this moment the Lab is involved in the commissioning of the demonstrator of the new European high resolution gamma-ray detector AGATA. The high segmentation of the instrument provides a good spatial resolution in addition to good energy measurement. Up to now two clusters of the detector have been installed and are ready to start the first exploitation of the detector for physics studies. AGATA will operate in connection with PRISMA and the total number of clusters to be installed at Legnaro will be five. 2. The future The program of the INFN for the Legnaro Laboratories in the next years is the development of SPES, a facility for RIB production in order to perform Radioactive Nuclei studies at the forefront of the nuclear physics. The idea is to benefit the two accelerators PIAVE and ALPI, as post accelerators for the selected radioactive beam, as well as the whole instrumentation available at the Lab. For the beam production many schemes have been elaborated. The ISOL method has been chosen for the production. In the first Technical Design Report it was studied that a facility based on a high intensity proton beam of 5 mA and 100 MeV, able to produce a fission rate as high as 1013 fission/s on an UCx target by two steps method i.e. converting the protons into neutrons and inducing the fission by neutrons. The project was thought to be a good prototype for the future EURISOL project too. Extensive R&D activity was developed for the different parts of the Linac, the neutron converter and the target. A proton source of 50 mA was developed at LNS (Catania) and sent to LNL. For this project at Legnaro the construction of a high intensity RFQ, able to accelerate the proton beam up to 5 MeV energy, is still under way. Extensive studies on the neutron converter and on the UCx target were performed with the support of Russian Labs and in collaboration with Ganil Lab. This activity is continuing in order to provide a neutron converter for the Ganil project SPIRAL2, while for the RIB production at Legnaro a different scheme was elaborated and presented at the last road-map discussion of the INFN. The new project is based on the consideration that the process of RIB production is much more efficient if the proton beam hits directly the UCx target in comparison with the two steps process. The problem of power deposited in the target was addressed. Optimizing the target design resulted in that it was possible to reach 1013 fissions/s in UCx target using a proton beam of 40-50 MeV and 200μA current. The UCx target is made of 7 slides, each one 1mm thick and 4cm in diameter opportunely mounted inside a high power target container. At this point the requested proton beam can be provided by a Cyclotron. A commercial Cyclotron with the requested characteristics is actually under commissioning at Nantes in France for the study of new radioisotopes. It can deliver two independent proton beams at the same time allowing the operation of two targets with a total intensity of 750 μA at a maximum energy of 70 MeV. A Cyclotron of this type is well suited for SPES: one line can provide the proton beam for the RIB production, the other one of 500 μA can have different applications like the radioisotope production as it is done at Nantes. The radioactive beams, which can become available with the new SPES version, have been evaluated extrapolating the data of the Oak Ridge RIB facility and are reported in Table 1.
66-76
72-79
72-84
75-84
86-94
89-96
90-97
111-118
110-120
115-124
116-128
123-134
124-135
129-138
134-144
139-146
141-145
Cu
Zn
Ga
Ge
Rb
Sr
Y
Pd
Ag
Cd
In
Sn
Sb
Te
Cs
Ba
La
10
+6
10
+8
10
+9
10
+7
10
+8
10
+9
10
85
3
15
15
10
10+8 +8
14
65
3
20
5
7
10+8
10
+7
10
+7
10
+8
10
+9
10
+7
10
+6
10
+6
10+6
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
UCx
SIS+LIS
SIS+LIS
SIS
LIS
LIS
LIS
SIS+LIS
LIS
LIS
LIS
LIS
SIS+LIS
SIS
LIS
LIS
LIS
LIS
Table 1: SPES Expected neutron rich beams Most Intense isotope (1/s) Ionization Eff (%) Target Ionization method 10+6 6 UCx LIS
LIS = Laser Ionization Source, SIS = Surface Ionization Source
Mass 65-69
Element Ni
***
***
*
****
***
**
**
**
**
****
****
***
*
***
**
**
**
R&D (difficulty) **
G. Puglierin / Nuclear Physics A 834 (2010) 713c–716c
715c
716c
G. Puglierin / Nuclear Physics A 834 (2010) 713c–716c
A proposal has been prepared also for the production of radioisotopes of interest for medical use: a possible list is reported in Table 2.
Table 2 Radionuclide production cross sections Radionu Target Reaction nat Cu-64 Ni Ni(p,n)
p-ener (MeV) 40
σM ax (mbarn) 50
Ni
64
Ni(p,n)
15
675
ZnO
68
Zn(p,2p)
70
25
Ga
69
Ga(p,2n)
45
100
Ga
69
Ga(p,2n)
20
550
RbCl
nat
Rb(p,4n)
50
100
Te
nat
Te(p,n)
53
150
*I-124
Te
124
Te(p,n)
12
590
*Re-186
W
W(p,n)
10
17
*Pd-103
Rh
103
Rh(p,n)
10
500
Th
232
Th(p,X)
70
60
Th
232
Th(p,X)
60
3
Th
232
Th(p,3n)
30
260
*Cu-64 Cu-67 Ge-68 *Ge-68 Sr-82 I-124
Th-228 Ac-225 *Pa-230
The proton energy that gives the largest cross-sections in the range 40-70 MeV (marked with *) has been considered.
On the same line to benefit the nuclear physics’ instruments development in order to provide opportunities in other fields, the program on the high intensity RFQ was focused on the completion of the accelerator, to realize a neutron source suitable for many applications, as the Boron Neutron Capture Therapy, which up to now has been realized with neutrons from a nuclear reactor. With this therapy it is possible to cure some tumors, the convenience of using a neutron source produced by an accelerator instead of a reactor is in the simplicity of the operations, cost and safety. With a neutron source other applications are possible as material science studies, radiation hardness and cross section measurements of interest for astrophysics or for the next generation of nuclear reactors. On the energy side, based on the experience in the construction of the high intensity RFQ, the Lab has taken the responsibility of the construction of the high intensity RFQ for the IFMIF project. IFMIF is the new machine, under construction by an international collaboration to study the material behaviours at neutron fluence rates similar to that present in the future fusion reactors. The RFQ is foreseen to accelerate a deuteron beam of 125 mA up to 5 MeV, with losses less than few per-cent. Acquiring experience with high intensity beam and the related problems may become very useful for future projects in high energy physics, in nuclear physics as well as in energy problems.