Physics with a Multi-MW Proton source Abstracts

## 1) Simulation of the horn and decay tunnel for a Super Beam project with SPL

Jean Eric Campagne and Antoine Cazes (PhD), Laboratoire de L'accélérateur Linéaire, Université Paris-Sud, BP34, Orsay Cedex, France

Subject: Particle Physics

Type of contribution:

I would like to present a study of the status of horn simulation in a super beam project with the SPL.

The talk may cover the full simulation program issue concerning :
- secondary particle energy deposition in horn materials with impact on the drawing,
- the focalisation of pions and the associated neutrino flux at the detector level.
- at energy above nominal proton 2.2GeV/c momentum, the neutrino background from kaons is discussed.
- Primary result on theta13 sensitivity (using Mauro Mezzetto code).
This work extends the pioneer work by Simone Gilardoni and Mauro Donega.

This talk could be no more than 15 minutes long.

## 2) A low-energy beta-beam facility

Maria Cristina VOLPE, Institut de Physique Nucleaire Orsay, Batiment 100, F-91406 Orsay cedex, France

Subject: Other

Type of contribution: Paper contribution

Recently, we have proposed to exploit the beta-beam concept to produce intense and pure low-energy neutrino beams of well-known fluxes [1]. Low energies means a few tens of MeV up to about a hundred MeV. Two configurations are possible: the ions are produced, brought inside a 4pi detector
and used as a neutrino source at rest; the ions are accelerated to different gamma values
producing neutrino beams of variable energy.

The idea of having a low-energy beta-beam facility opens new axis of research with respect to the original beta-beam project. A low-energy beta-beam facility would offer the possibility to improve our knowledge of non-standard neutrino properties, like the neutrino magnetic moment [2], as well as to perform systematic studies of neutrino-nucleus interactions, of interest for nuclear physics, particle physics and astrophysics [1,3]. In particular, the present upper limit on the neutrino magnetic moment
can be improved by about one order of magnitude [2]. Interesting neutrino-nucleus interaction rates can be obtained both with a small (GSI-like) and a large (CERN-like) storage rings [3].

Among the possible sites for a low-energy beta-beam facility CERN represents a unique site both for the intensities that can be achieved and the energies of the ions.

[1] C.Volpe,
"What about a beta-beam facility for low energy neutrinos?", to be published in Journal of Physics G [hep-ph/0303222].
[2] G.C. McLaughlin and C. Volpe,
"Prospects for detecting a neutrino magnetic moment with a tritium source and beta-beams", to be published in Physics Letters B [hep-ph/0312156].
[3] J. Serreau and C.Volpe,
""Neutrino-nucleus interaction rates at a low-energy beta-beam facility"", submitted to PRD [hep-ph/0403293].

## 3) Laser-driven proton sources: challenges and applications

S.V.Bulanov1,2, T.Esirkepov1,3, P.Migliozzi4, F.Pegoraro5, T.Tajima2, F.Terranova6

1) Advanced Photon Research Centre, JAERI, Kizu, Japan.
2) A. M. Prokhorov Institute of General Physics of RAS, Moscow,
Russia.
3) Moscow Institute of Physics and Technology, Dolgoprudny, Russia.
4) INFN, Sez. di Napoli, Napoli, Italy.
5) Dip. di Fisica, Univ. di Pisa and INFM, Pisa, Italy,
6) INFN, Laboratori Nazionali
di Frascati, Frascati, Italy.

Subject: High power proton drivers

Type of contribution: Poster

The acceleration of protons by the interaction of ultraintense laser beams with solid targets will probably open up a wealth of applications ranging from oncological hadron-therapy to laser-driven confinement fusion. On the other hand, a mechanism for efficient laser driven proton production is not available experimentally, yet. In this presentation we briefly review the laser-plasma interaction regime where the radiation pressure is dominant and the laser energy is transformed efficiently into the energy of fast ions and discuss the application of such plasma regimes to non-conventional high intensity proton drivers. We review the conditions under which this regime is operational and the main technological challenges connected to it. In fact, the pressure-dominated acceleration mechanism would allow a wide synergic scenario connecting the long term development of facilities for laser-driven inertial confinement fusion and the possibility to obtain an ultra-intense low-energy (1-2 GeV) proton driver for neutrino studies and spallation neutron sources. Among the neutrino-related applications we put emphasis on the $\nu_e$ appearance searches and we note that these facilities could allow for the first time study of subdominant $\nu_\mu \rightarrow \nu_e$ oscillations at the atmospheric scale with neutrinos produced by $\pi$ decays at rest or in flight.

4) RIASH: Radioactive Ions and Atoms in Superfluid Helium

P. Dendooven
KVI, Groningen, The Netherlands
J. Äystö, J. Huikari, IGISOL group
Department of Physics, University of Jyväskylä, Finland
W.X. Huang
Institute of Modern Physics, The Chinese Academy of Sciences, Lanzhou, China
K. Gloos
Ørsted Laboratory, Niels Bohr Institute, Copenhagen, Denmark
N. Takahashi
Osaka Gakuin University, Japan
J.P. Pekola
Low Temperature Laboratory, Helsinki University of Technology, Finland

Subject: Other

Type of contribution: Poster

The RIASH project investigates several issues related to radioactive ions and atoms in superfluid helium. The use of superfluid helium to stop high-energy radioactive ions and extract them as an ultra-cold ion beam is being developed. Proof-of-principle of this new technique was recently obtained by the authors [1]. Using superfluid helium as a storage medium for ions and atoms as well as the use of ions and atoms for probing the superfluid state are being looked at.
Some results and ideas will be presented. More particularly, the possibility to create radioactive muonic atoms inside superfluid helium will be explored. The potential of this alternative technique will be compared with other existing or proposed methods. The main items in this comparison are the technical challenges involved and the attainable muonic atom production rates.

[1] W.X. Huang, P. Dendooven, K. Gloos, N. Takahashi, J.P. Pekola, J. Äystö, Europhys. Lett. 63 (2003) 687.

### 5) Diamonds as a possible route to smaller emittances and higher intensities

Ulrik I. Uggerhoj, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C., Denmark

Subject: High power proton drivers

Type of contribution: Poster

In a charge exchange injection scheme, the replacement of the standard carbon stripping foil by diamond offers a range of advantages and essentially no drawbacks. Firstly, the
stripping efficiency of a diamond crystal is at least as large as for an amorphous foil of the same substance and thickness. Secondly, the emittance increase imposed by the multiple Coulomb scattering of the protons on subsequent turns is drastically lower by a factor of up to $\simeq$7. Thirdly, the restricted energy-loss of the protons is lower by a factor of up to $\simeq1.5$ - this, combined with the fact that the thermal conductivity of a single crystal of diamond is much higher than that of the amorphous material, will reduce the effect of heating of the stripping material. In high-power schemes based on amorphous foils heating of the electron stripping material is a limiting factor. Fourthly, the reduced total energy loss is accompanied by a smaller energy loss straggling implying a smaller longitudinal emittance. Lastly, the so-called random orientation of the crystal can provide the
option of stripping the H$^-$ ions as in an amorphous foil while preserving the advantage of a high thermal conductivity, simply by changing the orientation of the crystal. Thus, diamonds are a possibility to achieve very small emittances.

6) Development of a 3 MeV H- Test Stand at CERN

L.Bruno, F.Caspers, R.Garoby, J.Genest, K.Hanke, M.Hori, A.Lombardi, M.Magistris, A.Millich, M.Paoluzzi, C.Rossi, M.Silari, M.Vretenar (CERN), P.-Y.Beauvais (CEA), P.Ausset (CNRS).

Subject: High power proton drivers

Type of contribution: Poster

The development of high intensity pulsed proton sources requires a detailed study of the beam dynamics and innovative design of many critical components, going from the ion source to the beam diagnostics. Therefore, a 3 MeV Test Stand is under construction at CERN, which will be operated at nominal beam peak current, but at low duty cycle. The goal is to investigate the beam dynamics at low energy, with special emphasis on the CERN designed chopper line. Its purpose is to generate the required time structure of the beam, to clean the beam halo, and to match it to the rest of the accelerator. This project benefits from EU funding, within the framework of the Joint Research Activity HIPPI*), and will be based on an RFQ accelerator designed and built jointly by CEA and CNRS within the IPHI collaboration.

7) 3D Modeling of the Debuncher and Achromat

Subject: High power proton drivers

Type of contribution: Poster

PSI is involved in the development of a suite of powerful state-of-the-art modeling tools which enables us to gain quantitative understanding of space charge dominated beam transport. We use these tools mainly to perform beam dynamics studies on our CW cyclotron, delivering now up to 1.2 MW beam power on target with a proton final energy of 590 MeV. The general nature of one of the tools – Mad9p (Methodological Accelerator Design Version 9 Parallel) - a full 3d parallel tracking code with space charge allows us to perform beam dynamic studies beyond the usual tasks at PSI. In the frame of the CERN studies for a Neutrino Factory we performed calculations of the Debuncher and the 2.2 GeV Achromat. We show results and discuss the possibilities for a full accumulator ring simulation.

8) CUPP - Centre for Underground Physics in Pyhäsalmi

Timo Enqvist and Chanqguan Shen
CUPP, P.O. Box 22, FIN-86801 Pyhäsalmi, Finland

T. Jämsen, M. Lehtola, M. Mutanen, J. Narkilahti, S. Nurmenniemi, and
J. Peltoniemi
CUPP, P.O. Box 3000, FIN-90014 University of Oulu, Finland

Subject: Other

Type of contribution: Poster

The CUPP project aims at establishing an underground research centre in the Pyhäsalmi mine in Pyhäjärvi, Finland. It is the deepest operational base-metal mine in Europe. The mine can be divided into two parts: the old mine and the new mine. The new mine extends down to 1440 metres where the mining operation is going. The existing caverns of the old mine, situating on the top of the new mine at depths 95-1080 m, can be used for scientific purposes at the moment.

The site provides excellent opportunities for the research of underground physics by having very stable bedrock, low background radiation level, modern infrastructure, and good traffic conditions all around a year. The neutrino background due to nuclear reactors is the smallest among the European underground laboratories.

The present activities focus on cosmic ray experiments. A multimuon experiment at shallow depth is under construction, using recycled muon chambers from CERN. Neutrino experiments are under consideration.

The construction of new large-volume underground laboratory rooms, at the depth of about 1500 metres, corresponding 4200 mwe, is technically possible and economically feasible. The laboratory rooms could host far detectors of the future long-baseline neutrino oscillation experiments. For example, the distance between Pyhäjärvi and CERN is 2288 km, which is very interesting for neutrino studies. The baseline and its density profile have been modelled very accurately, and simulations for the neutrino factory are going on.

Observing neutrinos from a multi-MW machine in Pyhäsalmi provides an interesting option. There is no technical obstacle for excavating the large volume detector caverns, up to one million cubic metres like UNO, if their shape can be optimised.

9) Other Study on a Mono-modal Accelerating Cavity based on Photonic Band-gap Concepts

A. Andreone, E. Di Gennaro, F. Francomacaro, G. Lamura
Dipartimento di Scienze Fisiche and I.N.F.M. Coherentia, Università degli Studi di Napoli Federico II, Napoli

M.R. Masullo
I.N.F.N. Sezione di Napoli

V.G. Vaccaro
Dipartimento di Scienze Fisiche and I.N.F.N. Sezione di Napoli, Università degli Studi di Napoli Federico II, Napoli

Vincenzo Palmieri, Giorgio Keppel and Diego Tonini
I.N.F.N.- LNL

Subject: High power proton drivers

Type of contribution: Poster

One of the main problems of present and future experiments with high intensity beams is the presence of high order modes (HOMs) which might degrade the beam quality. Accelerating cavities require HOMs suppression while keeping high quality factor (Q) fundamental mode. Both these requirements can be hardly met in closed metallic cavities. In low frequency cases and for particular geometries it is possible to partially suppress HOMs, but at high frequencies and for superconducting cavities configuration becomes cumbersome and technically unviable).
We propose here a new type of a high gradient, high Q accelerator cavity based on Photonic Band Gap (PBG) concepts and operating in the microwave region. The structure consists of a two-dimensional lattice, where posts (dielectric, metallic or superconducting) are sandwiched by two conducting or superconducting plates. This sandwich exhibits two kinds of frequency bands: “pass-bands” and “stop-bands”. Defect modes can be localized inside the lattice in an equivalent cavity obtained by removing posts. In this way, one can obtain a quasi-mono-modal cavity with a high Q fundamental mode and HOMs falling into the pass bands. Due to its intrinsic monomodal behaviour the PBG cavity can be easily scaled to different frequencies. Here, we will present our studies on different prototypes (Copper and metallic/dielectric) working in the 2-20 GHz range. The related RF measurements (scattering parameters) carried out at room and cryogenic temperature on the prototypes are shown as well.