Solid Hydrogen Target
Development of a Solid Hydrogen Target to Study the Nature of Scalar Mesons
Tech Area / Field
- PHY-PFA/Particles, Fields and Accelerator Physics/Physics
- MAN-MCH/Machinery and Tools/Manufacturing Technology
8 Project completed
Senior Project Manager
Malakhov Yu I
ITEF (ITEP), Russia, Moscow
- Hrunichev Cosmic Scientific-Plant Center / Design Bureau „Salyut“, Russia, Moscow\nMoscow Power Engineering Institute, Russia, Moscow\nPilugin's Scientific-Plant Center of Automatics, Russia, Moscow
- Forschungszentrum Jülich, Germany, Jülich
Project summaryCOSY is a proton synchrotron with a maximum beam energy of 2.6 GeV operated at the Institut für Kernphysik (IKP) of the Forschungszentrum Jülich (FZJ). It allows high-precision studies in the field of medium-energy hadron physics. One of the larger installations at COSY is the ANKE spectrometer which has been built by the FZJ and an international collaboration with approx. 100 members mostly from Germany and Russia. The inpidual experiments at ANKE are carried out by sub-groups which provide the detectors and installations needed for a particular measurement.
The goal of the current project is the development and operation of a new target complex at ANKE. This target will, in a first series experiments, be used for measurements from which information about the nature of scalar mesons a0 and f0 is expected . The scalar mesons play a very important role in the physics of hadrons. Nevertheless, the structure of the lightest scalar mesons a0(980) and f0(980) is not completely understood yet.
The production cross sections for a0 mesons at COSY energies is rather low. According to theoretical calculations, cross sections smaller than 1µb are expected. Thus it is necessary to work at high luminosities, L>1032s-1×cm-2. In order to achieve such high luminosities at ANKE an effective target thickness of ~1016 atoms/cm2 at a proton-beam intensity n~1011 is desirable. Since it is planed to study meson production in pp and pn collisions, the target material should be hydrogen or deuterium. The only device which fulfills these requirements is a frozen-droplet target. Actually, a prototype target has been designed and constructed at ITEP [2-4].
In a series of tests of the main components as vacuum cryostat, the cryogenic and hydrogen supply systems, the design parameters were reached and the first production of liquid hydrogen droplets was demonstrated. Consequently, the major parts of the prototype target system were transported to the IKP of FZ Jülich. It is planned to install it at the ANKE spectrometer at COSY, to bring it in operation to gain experience and to optimize the set-up.
In parallel at the experimental facilities of ITEP and MPEI in Moscow systematic investigations continue in order to achieve the production of frozen gas pellets which is mandatory for the final ANKE set-up. A modified droplet generator and triple-point chamber for different kinds of target gases have to be developed and are being tested. This work program will be performed mainly by weapon specialists from ITEP and participating institutes, and is an important part of the proposed project.
The potential applications of the technology to be developed and produced are very broad. They include the development of a new generation of micro-targets for precise accelerator experiments in elementary-particle and nuclear physics. The possible industrial applications include the production of mono-sized micro particles from different kinds of materials, for example, metals and medical substances. Another important field of activity is the development of cryogenic generators/injectors of mono-dispersed droplets from condensed gases.
1. L. Kondratyuk et al., ”Study of a0 mesons in the reaction pp → da0+ → dK+K0 at ANKE”, preprint ITEP 18-97, Moscow 1997.
2. A. Bukharov et al., ” A pellet target for ANKE” FZ-Jülich Annual Report 1998.
3. A. Bukharov et al., ”Pellet target for experiments on internal beam of accelerators”, Int.Conf. CRYO-98, Prague, May 1998.
4. M. Büscher et al., ”Status of pellet target preparation for ANKE”, FZ-Jülich Annual Report 1999.