Status Report and Beam-Time Request for COSY experiment #199 Spin–Filtering Studies at COSY

We report on the progress of the PAX experimental programme since the last PAC meeting. During summer shutdown 2009 four new quadrupole magnets and a modified vacuum system have been installed into the COSY ring to form a section with low β functions. With the successful commissioning of this low-β insertion in January 2010 it has also been discovered that intra-beam scattering effects are likely limiting the beam lifetime. In order to get these effects under control and to improve the lifetime, to commission a new detection system, and to finally perform a first series of spin–filtering measurements with transverse polarisation, we request ten weeks of beam time. Content

Beam Request Spin-Filtering Studies at COSY

Summary of experiment: We report on the progress of the PAX experimental program since the last PAC meeting. During two blocks of each three weeks beam development intercepted by two weeks of maintenance, systematic machine studies have been carried out. An effective procedure for setting up the machine with the low-β section and a target cell at the new PAX-IP in order to achieve high beam lifetimes has been developed. The effect of flow-limiters and one NEG-pump on the beam lifetime has been studied, as well as the effect of different beam emittances and beam intensities on the beam lifetime. Even though by increasing the beam emittance a reproducible maximum for the beam lifetime was achievable, no effect of the beam intensity was seen and therefore no clear observation of the so-called Touschek-effect was possible. Nevertheless, we learned how to gain a sufficient beam lifetime for spin-filtering studies at COSY and apply for 3 weeks of beam development followed by 4 weeks of beam time

Spin Filtering Studies at COSY

none114Understanding the interplay of the nuclear interaction with polarized protons and the electromagnetic interaction with polarized electrons in polarized atoms is crucial to progress towards the PAX goal to eventually produce stored polarized antiproton beams at FAIR. Presently, there exist two competing theoretical scenarios: one with substantial filtering of (anti)protons by atomic electrons, while the second one suggests a self-cancellation of the electron contribution to filtering. The issue can be clarified by studying the energy dependence of the polarization buildup in a proton beam at COSY at energies in the range from 20 to about 800 MeV. This Letter-of-Intent summarizes the physics case and possible experimental approaches to these studies at COSY.noneC. Barschel; U. Bechstedt; J. Dietrich; N. Dolfus; R. Engels; R. Gebel; H. Hadamek; J. Haidenbauer; C. Hanhart; A. Kacharava; G. Krol; M. K¨uven; G. Langenberg; A. Lehrach; B. Lorentz; R. Maier; S. Martin; U.-G. Meißner; M. Nekipelov; N.N. Nikolaev; D. Oellers; G. d’Orsaneo; D. Prasuhn; F. Rathmann; M. Retzlaff; J. Sarkadi; R. Schleichert; H. Seyfarth; A. Sibirtsev; D. Sp¨olgen; H.J. Stein; H. Stockhorst; H. Str¨oher; Chr. Weidemann; D. Welsch; and P. Wieder; L. Barion; S. Bertelli; V. Carassiti; G. Ciullo; M. Contalbrigo; A. Cotta–Ramusino; P.F. Dalpiaz; A. Drago; G. Guidoboni; P. Lenisa; L. Pappalardo; G. Stancari; M. Stancari; M. Statera; T. Azarian; A. Kulikov; V. Kurbatov; G. Macharashvili; S. Merzliakov; I.N. Meshkov; A. Smirnov; D. Tsirkov; u. Uzikov; F.M. Esser; R. Greven; G. Hansen; H. Jadgfeld; J. Kieven; F. Klehr; A. Schwaab; H. Soltner; H. Straatmann; S. Barsov; S. Belostotski; K. Grigoryev; P. Kravtsov; M. Mikirtychiants; S. Mikirtychiants; A. Vasilyev; D. Chiladze; A. Garishvili; N. Lomidze; D. Mchedlishvili; M. Nioradze; M. Tabidze; N. Akopov; A. Avetisyan; G. Elbakyan; H. Marukyan; and S. Taroian; P. Benati; W. Erven; F.–J. Kayser; H. Kleines; and P. W¨ustner; D. Bruncko; J. Ferencei; J. Muˇsinsk´y; and J. Urb´an; W. Augustyniak; B. Marianski; A. Trzcinski; P. Zupranski; S. Dymov; A. Nass; and E. Steffens; K. Rathsman; P.–E. Tegn´er; and P. Th¨orngren Engblom; A.I. Milstein; Y. Shatunov; and V.M. Strakhovenko; R. De Leo; and G. Tagliente; B. K¨ampfer; and S. Trusov; N. Buttimore; H.O. MeyerC., Barschel; U., Bechstedt; J., Dietrich; N., Dolfus; R., Engels; R., Gebel; H., Hadamek; J., Haidenbauer; C., Hanhart; A., Kacharava; G., Krol; M., K¨uven; G., Langenberg; A., Lehrach; B., Lorentz; R., Maier; S., Martin; U. G., Meißner; M., Nekipelov; N. N., Nikolaev; D., Oellers; G., D’Orsaneo; D., Prasuhn; F., Rathmann; M., Retzlaff; J., Sarkadi; R., Schleichert; H., Seyfarth; A., Sibirtsev; D., Sp¨olgen; H. J., Stein; H., Stockhorst; H., Str¨oher; Weidemann, C. h. r.; D., Welsch; P., Wieder; Barion, Luca; Bertelli, Susanna; Carassiti, Vittore; Ciullo, Giuseppe; Contalbrigo, Marco; COTTA RAMUSINO, Angelo; Ferretti, Paola; Drago, Alessandro; Guidoboni, Greta; Lenisa, Paolo; Pappalardo, Luciano Libero; Stancari, Giulio; Stancari, Michelle Dawn; Statera, Marco; T., Azarian; A., Kulikov; V., Kurbatov; G., Macharashvili; S., Merzliakov; I. N., Meshkov; A., Smirnov; D., Tsirkov; U., Uzikov; F. M., Esser; R., Greven; G., Hansen; H., Jadgfeld; J., Kieven; F., Klehr; A., Schwaab; H., Soltner; H., Straatmann; S., Barsov; S., Belostotski; K., Grigoryev; P., Kravtsov; M., Mikirtychiants; S., Mikirtychiants; A., Vasilyev; D., Chiladze; A., Garishvili; N., Lomidze; D., Mchedlishvili; M., Nioradze; M., Tabidze; N., Akopov; A., Avetisyan; G., Elbakyan; H., Marukyan; S., Taroian; P., Benati; W., Erven; Kayser, F. –. J.; H., Kleines; P., W¨ustner; D., Bruncko; J., Ferencei; J., Muˇsinsk´y; J., Urb´an; W., Augustyniak; B., Marianski; A., Trzcinski; P., Zupranski; S., Dymov; A., Nass; E., Steffens; K., Rathsman; Tegn´er, P. –. E.; P., Th¨orngren Engblom; A. I., Milstein; Y., Shatunov; V. M., Strakhovenko; R., De Leo; G., Tagliente; B., K¨ampfer; S., Trusov; N., Buttimore; H. O., Meye