1. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 1 SLAC Computer Building (Bldg 50, Room 115), SLAC Thursday, January 24, 2008 BLM Calibration— LCLS Undulator Radiation Loss Simulations with MARS Jeff Dooling Argonne National Laboratory

2. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 2 Outline Simulation Tasks Modeling with MARS Status

3. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 3 Tasks 1a) Complete first undulator geometry in MARS 1b) Full undulator geometry with quad fields 2) Use equivalent 1-  m Al foil to initiate shower for calibration. Begin with foil 30 m upstream. 3)Beam offsets a)x o =30  m, y o =0 b)x o =0, y o =30  m c)x o =30  m, y o =30  m 4) Direct beam strike on chamber walls

4. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 4 Tasks, con’t 5) Calibration for tests at ANL—loss scenarios a) Touschek—single electron (linear, but random), loss rate known b) Injection—10 4 e/m (mainly linear, deterministic), losses known c) Dump (10 10 e/m highly saturated)

5. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 5 Task—Calibration, APS SR Injection losses S4 Cerenkov detector[1] signal during Top-Up injection Losses occur for several ms Losses occur on each cycle around the SR S3 beamline removed; S4, smallest aperture —40% of inj loss [2] zooming

6. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 6 Modeling with MARS— Simulation considerations Keep STEPEM~0.1t min, where t is the smallest linear size of the smallest region (for example, beam pipe wall thickness 0.05 mm; therefore STEPEM=0.005 cm) KILLPTCL (sub)—keep or throw away primary electrons (for example, with primary energy E o, discard all particles with energies above E o -  E where  E>  pc)

7. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 7 Simulation considerations, con’t MIXTUR (sub)—define special mixtures such as vanadium permendur and its combination with magnets (NdFeB). SUFI and FIELD (sub)—used to read in magnetic field maps for the quadrupoles

8. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 8 Magnet and Pole material Undulator volume mixture of magnet and pole material Magnet: NdFeB—mixture: 6% B, 82% Fe, and 12% Nd [MARS Manual] (~Nd 3 Fe 53 B 20 ) Poles: Vanadium Permendur (VP)—mixture: 2% V, 49% Fe, 49% Co [3] (~V 2 Fe 45 Co 43 )

9. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 9 2-D Quad Field profiles from OPERA Field maps courtesy of M. Jaski

10. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 10 Zooming in on beam region Outside linear (beam) region, fields are complex and non-focusing

11. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 11 Adding a pole “foam” region adjacent to the beamline Y-Z undulator cross section beam pipe OD: 0.300 cm magnet height: 0.338 cm pole height: 0.390 cm Mechanical drawings courtesy of S. Doran and R. Keithley

12. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 12 Simulation stats on the APS weed cluster running MARS (MPI) for single undulator, no B fields 10 proc., 10 6 primary particles, w/ enh., 13 min. 8 proc., 10 7 primary particles, w/ enh., 118 min. 24 proc., 10 7 pri. part., no enh., 44 min. (2*) 24 proc., 10 7 pri. part., w/ enh., 44 min.* Ave. speed: 9.4x10 3 pp-und/proc./min Approx. 300 proc. available on weed of which 250 can be requested a by single user *varied seed

13. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 13 Simulation geometries, single undulator x-y view at z=25 cm y-z view at x=0 cm

14. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 14 MARS geometry x-y view at z=25 cm, zoom x-y view at z=13.5 cm, radiator

15. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 15 Preliminary results 10E7 Al foil 30 m upstream neutron flux electron flux

16. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 16 Radiator e-spectra with and without enhancer without W enhancer with W enhancer

17. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 17 Status and Goals Task 1a) 1 st undulator geometry in MARS— initially early Jan 08; accomplished now Task 1b) Full geometry with fields—15Feb08 Task 2—29Feb08 Task 3—15Mar08 Tasks 4 and on—must be negotiated

18. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 18 Final thought Work quickly, but don’t hurry. —John Wooten

19. BLM PDR Thursday January 24, 2008 Jeff Dooling jcdooling@anl.gov 19 References 1.A. Pietryla, W. Berg, R. Merl, Proc. PAC01, Chicago, IL, http://accelconf.web.cern.ch/AccelConf/p01/PAPERS/TPAH304.pdf 2.M. Borland and L. Emery, Proc. PAC05, Knoxville, TN, http://ieeexplore.ieee.org/iel5/10603/33511/01591640.pdf; updated by private communication with L. Emery 14Jan08 http://ieeexplore.ieee.org/iel5/10603/33511/01591640.pdf R. E. Burket and D. M. Stewart, J. Appl. Phys. 33, 1224 (1962).