Author: Wuestefeld, G.     [Wüstefeld, G.]
Paper Title Page
TUOAB02 Simultaneous Long and Short Bunch Operation in an Electron Storage Ring - a Hybrid Mode based on Nonlinear Momentum Compaction 945
 
  • M. Ries, J. Feikes, A. Jankowiak, P.O. Schmid, G. Wüstefeld
    HZB, Berlin, Germany
  
  The gen­er­a­tion of short puls­es in elec­tron stor­age rings is driv­en by dif­fer­ent user groups like time re­solved x-ray spec­troscopy users or users of co­her­ent syn­chrotron ra­di­a­tion. The re­quired op­tics and op­er­a­tion con­di­tions to gen­er­ate this short bunch­es are wors­en­ing the ex­per­i­men­tal con­di­tions, e.g. strong­ly re­duc­ing the av­er­age pho­ton flux, for the reg­u­lar user. There­fore short bunch op­er­a­tion is usu­al­ly lim­it­ed to ded­i­cat­ed user shifts. By con­trol­ling high­er or­ders of the mo­men­tum com­paction fac­tor by high­er mul­ti­poles it is pos­si­ble to in­tro­duce a hy­brid mode and si­mul­ta­ne­ous­ly sup­ply­ing long and short bunch­es*. The Metrol­o­gy Light Source (MLS) has the means to con­trol these high­er or­ders**, there­fore it is an ideal ma­chine to in­ves­ti­ate the fea­si­bil­i­ty of such a hy­brid mode. Track­ing re­sults and first mea­sure­ments will be shown.
* D. Robin et al., Proc. of EPAC08, p. 2100-2102, Genoa, Italy (2008).
** J. Feikes et al., Phys. Rev. ST Accel. Beams 14, 030705 (2011). 		 
slides icon Slides TUOAB02 [7.817 MB]  
 
TUPC072 Accurate Electron Beam Size Measurement at the Metrology Light Source 1165
 
  • R. Klein, G. Brandt, R. Thornagel
    PTB, Berlin, Germany
  • J. Feikes, M. Ries, G. Wüstefeld
    HZB, Berlin, Germany
  
  For the op­er­a­tion of the Metrol­o­gy Light Source (MLS)*, the ded­i­cat­ed elec­tron stor­age ring of the Physikalisch-Tech­nis­che Bun­de­sanstalt (PTB), as the na­tion­al pri­ma­ry ra­di­a­tion source stan­dard from the near in­frared to the vac­u­um ul­tra­vi­o­let spec­tral re­gion, all stor­age ring pa­ram­e­ters which are rel­e­vant for the cal­cu­la­tion of the ra­di­ant in­ten­si­ty by the Schwinger equa­tion have to be known ab­so­lute­ly with small un­cer­tain­ties. For the mea­sure­ment of the ef­fec­tive ver­ti­cal elec­tron beam size a Bragg po­larime­ter, op­er­at­ing at a pho­ton en­er­gy of 1103 eV, has been de­signed and put into op­er­a­tion. This sys­tem also serves as a de­tec­tion sys­tem for the image of the elec­tron beam through a set of nar­row slits. The re­sults ob­tained with the new de­vice are com­pared to those mea­sured by an op­ti­cal beam imag­ing sys­tem**.
* R. Klein et al., Phys. Rev. ST-AB 11, 110701 (2008).
** C. Koschitzki et al., Proc. IPAC10, 894-896 (2010). 		 
 
THPC012 Mitigating the Pertubations Caused by U 180 at the Metrology Light Source 2930
 
  • P.O. Schmid, D.B. Engel, J. Feikes, M. Ries, G. Wüstefeld
    HZB, Berlin, Germany
  
  The Metrol­o­gy Light Source is equipped with an elec­tro­mag­net­ic un­du­la­tor with a pe­ri­od length of 180 mm. User re­quests de­mand op­er­a­tion of this un­du­la­tor in a wide en­er­gy range from 100 MeV through 629 MeV for user and ded­i­cat­ed low alpha modes. Mit­i­gat­ing the per­tu­ba­tions caused by the un­du­la­tor to an ac­cept­able level for all user re­quests, re­quires each quadrupole in the lat­tice to be pow­ered in­di­vid­u­al­ly. To what ex­tend this re­cent­ly im­ple­ment­ed ca­pa­bil­i­ty al­lows the restora­tion of the main prop­er­ties of the ma­chine op­tics for var­i­ous set­tings of the un­du­la­tor is pre­sent­ed in this doc­u­ment.  
 
THPC013 THz Studies at a Dedicated Beamline at the MLS 2933
 
  • R. Müller, A. Hoehl, A. Serdyukov, G. Ulm
    PTB, Berlin, Germany
  • J. Feikes, M. Ries, G. Wüstefeld
    HZB, Berlin, Germany
  
  The Physikalisch-Tech­nis­che Bun­de­sanstalt (PTB), the Ger­man na­tion­al metrol­o­gy in­sti­tute is op­er­at­ing the low-en­er­gy elec­tron stor­age ring Metrol­o­gy Light Source (MLS) in Berlin-Adler­shof in close co­op­er­a­tion with the Helmholtz-Zen­trum Berlin. The MLS is de­signed and pre­pared for a spe­cial ma­chine op­tics mode (low-al­pha op­er­a­tion mode) based on a sex­tupole and oc­tupole cor­rec­tion scheme, for the pro­duc­tion of co­her­ent syn­chrotron ra­di­a­tion in the THz re­gion*. At the MLS two bend­ing mag­net beam­lines ded­i­cat­ed to the use of IR and THz syn­chrotron ra­di­a­tion are in op­er­a­tion: the MLS-IR beam­line op­ti­mized for the NIR to FIR, and a ded­i­cat­ed THz beam­line op­ti­mized for the FIR/THz spec­tral range**. Low-al­pha op­er­a­tion optic modes for dif­fer­ent ring en­er­gies, 250 MeV, 350 MeV, 450 MeV and 630 MeV are avail­able. We com­pare the THz spec­tra taken in the dif­fer­ent low-al­pha modes and dis­cuss the re­sults.
* J. Feikes et al., Phys. Rev. ST Accel. Beams 14, 030705 (2011).
** R. Müller et al., J. Infrared Milli Terahz Waves, in press (2011), DOI: 10.1007/s10762-011-9785-6. 		 
 
THPC014 Simultaneous Long and Short Electron Bunches in the BESSY II Storage Ring 2936
 
  • G. Wüstefeld, A. Jankowiak, J. Knobloch, M. Ries
    HZB, Berlin, Germany
  
  A scheme is dis­cussed, where short and long bunch­es can be stored si­mul­ta­ne­ous­ly in the BESSY II stor­age ring. With re­cent de­vel­op­ments in sc-rf cav­i­ty tech­nol­o­gy it be­comes pos­si­ble, to in­stall high gra­di­ent cav­i­ties in elec­tron stor­age rings. With an ap­pro­pri­ate choice of these cav­i­ties sta­ble fixed points with dif­fer­ent rf-volt­age gra­di­ents are avail­able, lead­ing to dif­fer­ent zero cur­rent bunch lengths. For BESSY II, we dis­cuss the si­mul­ta­ne­ous­ly stor­age of bunch­es with rms-lengths of 2 ps and 15 ps at high beam in­ten­si­ties. Ad­di­tion­al­ly, in a low alpha op­tics sub-ps and ps-bunch­es are pos­si­ble and a dou­ble buck­et op­tics can be set up to store the two types of beams si­mul­ta­ne­ous­ly on dif­fer­ent or­bits. Ul­tra-short and long bunch­es can be sup­plied to the users, sep­a­rat­ed by slight­ly dif­fer­ent or­bits.  
 
THPC010 Recent Developments at the Metrology Light Source 2927
 
  • J. Feikes, T. Birke, O. Dressler, D.B. Engel, F. Falkenstern, B. Franksen, A. Heugel, H.-G. Hoberg, F. Hoffmann, J. Kuszynski, J. Rahn, M. Ries, P.O. Schmid, T. Schneegans, D. Schüler, G. Wüstefeld
    HZB, Berlin, Germany
  • K.B. Bürkmann-Gehrlein, V. Dürr, H.G. Glass, G. Schindhelm
    BESSY GmbH, Berlin, Germany
  • R. Klein
    PTB, Berlin, Germany
  
  The Physikalisch-Tech­nis­che Bun­de­sanstalt (PTB), the Ger­man na­tion­al metrol­o­gy in­sti­tute, owns the elec­tron stor­age ring Metrol­o­gy Light Source (MLS) which was built and is op­er­at­ed by the Helmholtz-Zen­trum Berlin [1, 2]. The MLS has been in reg­u­lar user op­er­a­tion since April 2008 and sup­ports syn­chrotron-ra­di­a­tion-based metrol­o­gy and tech­no­log­i­cal de­vel­op­ments in the IR, UV, VUV and EUV spec­tral range. Here we re­port on re­cent progress to de­vel­op the MLS into a re­li­able, flex­i­ble and sta­ble user fa­cil­i­ty.  
 
THPC154 Shimming of the Dynamic Field Integrals of the BESSY II U125 Hybrid Undulator 3248
 
  • J. Bahrdt, W. Frentrup, A. Gaupp, M. Scheer, I. Schneider, G. Wüstefeld
    HZB, Berlin, Germany
  
  With­in a con­tin­u­ous pro­gram the BESSY II un­du­la­tors are pre­pared for Top­ping-Up op­er­a­tion. The BESSY II U125 pla­nar hy­brid un­du­la­tor has a pe­ri­od length of 125 mm and a pole width of only 60 mm. The hor­i­zon­tal de­fo­cus­ing of the 1.7 GeV e-beam may re­sult in a sig­nif­i­cant re­duc­tion of the hor­i­zon­tal dy­nam­ic aper­ture, re­duc­ing the in­jec­tion ef­fi­cien­cy when in­ject­ing into the closed gap. The dy­nam­ic field in­te­grals are de­rived from a 2D-Fouri­er de­com­po­si­tion of the 3D-field. An an­a­lyt­ic de­scrip­tion of the dy­nam­ic mul­ti­poles based on the Fouri­er co­ef­fi­cients is pre­sent­ed. Magic fin­gers have been in­stalled in order to min­i­mize the dy­nam­ic field in­te­grals and to en­large the good field re­gion of the de­vice.  
 
THPC155 Modification of the BESSY II Optic for the Implementation of a Small Gap Undulator 3251
 
  • J. Bahrdt, K.B. Bürkmann-Gehrlein, V. Dürr, W. Frentrup, A. Gaupp, A. Jankowiak, P. Kuske, J. Rahn, M. Scheer, P.O. Schmid, G. Wüstefeld
    HZB, Berlin, Germany
  
  At BESSY there is an in­creas­ing de­mand for pho­tons in the range from 60 eV to 8 keV avail­able at the same ex­per­i­men­tal sta­tion. The pho­tons will be pro­duced by a com­bi­na­tion of two ad­ja­cent un­du­la­tors, one of them will be a small pe­ri­od cryo­genic un­du­la­tor. Sev­er­al op­tics schemes for the 1.7 GeV BESSY II stor­age ring are dis­cussed to in­stall the un­du­la­tors. Two types of straight sec­tions exist. A high beta straight with betaxmin=15 m and betaymin=4.5 m and a low beta straight with betaxmin=betaymin=1 m. We dis­cuss the pre­sent plan, which clear­ly favours a small de­tun­ing of an ex­ist­ing low beta straight to shift the low beta waist to the cen­tre of the low gap un­du­la­tor, with only minor im­pact to the ma­chine.