• P. Kuske, P.O. Schmid
  Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin
• R. Görgen, J. Kuszynski
  Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Elektronen-Speicherring BESSY II, Berlin

With a 7T wig­gler in op­er­a­tion any at­tempts to de­tect the res­o­nant de­po­lar­iza­tion of the elec­tron spins were un­suc­cess­ful at BESSY II. This was at­tribut­ed to the severe­ly re­duced final de­gree of spin po­lar­iza­tion in the al­ter­nat­ing fields of the strong wig­gler which on the other hand near­ly dou­ble the ra­di­a­tion loss per turn. The key to a clear de­tec­tion of the de­po­lar­iza­tion were the im­prove­ment of the sen­si­tiv­i­ty of the po­larime­ter based on the spin de­pen­dent Tou­schek scat­ter­ing cross sec­tion and the more ef­fec­tive and thus full de­po­lar­iza­tion of the beam. In the paper the steps taken will be pre­sent­ed in de­tail. With these im­prove­ments in place the high pre­ci­sion en­er­gy de­ter­mi­na­tion of the stored beam can be per­formed once again in par­al­lel to the nor­mal user op­er­a­tion and with­out any no­tice­able per­tur­ba­tions to the beam.

• P.O. Schmid, P. Kuske
  Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin
• D.B. Engel, J. Feikes, R. Müller, G. Wüstefeld
  Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Elektronen-Speicherring BESSY II, Berlin

In this paper we pre­sent the re­sults of our stud­ies em­ploy­ing LOCO and MML for op­tics cal­i­bra­tion at the MLS and at the BESSY II stor­age rings. Both the stan­dard user modes and ded­i­cat­ed low alpha modes were anal­ysed.