ANKE (Apparatus for Studies of Nucleon and Kaon Ejectiles) is a large acceptance forward magnetic spectrometer at an internal target station in the COSY ring. The central dipole is movable to adjust the momenta of the detected particles independent of the beam momentum. Using deuterium (cluster and gas) targets, reactions on the neutron are tagged by detecting the low-energy recoil proton in silicon strip detectors in vacuum next to the target. In addition, a Polarized Internal Target (PIT) with a storage cell are in use for double-polarized measurements.
An openable storage cell has been constructed recently and is ready for operation. The data taking is going on at a good rate and the publication record is excellent.
In 2005 a SPIN program was outlined to exploit the possibilities of carrying out experiments with polarized beams and targets at ANKE (see here). Since this time many results relevant to good undestanding of the principal goals of nuclear and hadronic physics has been achieved and now, with the new hardware, collaboratrion is ready to finalize program in the following topics (proposals):
- double-polarized experiments in Nucleon-Nucleon (mainly pn) sector;
- double-polarized experiment in close to threshold pion production in pn collision;
- double-polarized experiment in strangness production (lambda hyperon).
Technical developments at ANKE
The collaboration has been and still is very active and successful at implementing new hardware.
Polarized Internal Terget (PIT)
Since 2005 the ANKE spectometer has been equipped with a Polarized Internal Traget. The PIT consists of: Atomic Beam Source (ABS), vacuum target chamber, and a Lamb-Shift Plarimeter (LSP). Using the polarized Hydrogen and Deuterium gas targets collaboration have embarked to measure the spin dependence of many nuclear reactions.
The commissioning of the openable (closable) storage cell for polarized gas targets at ANKE has been conducted successfully. The cell operated in a very stable and reliable way. A desired beam intensity from COSY has been achieved, when passing a pre-cooled stacked beam through the cell. The gain factor in density of the (hydrogen/deuterium) gas target of the order of 5 has been demonstrated, which is close to the expected figure. In a titanium cell a high degree of polarisation of hydrogen (85%) and deuterium (70%) has been obtained.
Silicon Tracking Telescopes (STT)
A very efficient silicon tracker telescopes for spectator (low energetic) recoil particles has been operating at ANKE since from the first experiments.