1. Design and Performance Expectation of ALPHA accelerator S.Y. Lee, IU 2/26/2009 1. Introduction 2. Possible CIS re-build and parameters 3. Issues in the Design of a small electron Synchrotron. 4. Compact photon source 5. Accelerator parameters and performance expectation

2. Problems of CRANE Linac in Radiation effect experiments:

3. –Parameter Requirement Goal –Dose Rate 1E12 rads/sec 5E12 rads/sec –Pulse width (narrow) 10 - 50 nsec 5 - 100 nsec –Pulse width (wide) ` 1 - 5 usec 1 - 10 usec –Beam spot size (85% uniformity) 40 mm (diam) 65 mm (diam) –Pulse rep rate 10 shots/sec 50 shots/sec –Energy 40 - 60 MeV –No RF spikes in beam on target –Bremstrahlung Mode 2 – 3 cal/cm2 Our goal is to design a machine that can provide beam debunching, beam accumulation for radiation effect experiments and generate X- ray photons for future applications for both CRANE NSWC and IU Science Communities.

4. CIS: Circumference =17.364 m, Inj KE= 7 MeV, extraction: 240 MeV Dipole length = 2 m, 90 degree bend, edge angle = 12 deg. ALPHA: No constraint on circumference (C=20m). Use CIS dipoles & cavity; Need Damping wigglers, chicane, electrostatic kickers & septum

5. Using a single quadrupole as in the DBA Not a good idea!

6. 1.Quadrupole does not work 2.How about Robinson wiggler? – not effective in changing J x 3.Gradient Damping wiggler a.Maximize straight section so that there are space for future applications b.Make it easy to operate c.C=20 m, B 1 /B 0 =1.9 m -1. (AGS: B 1 /B 0 =4.1 m -1 ) Damping wiggler Chicane for laser-electron interaction cavity Lambertson septum Injection kickers

7. Pulse from linac Extracted beam Lambertson septum Kicker 1 Kicker2 1.Beam in and out in one revolution satisfies the CRANE requirement of steady state experiment. 2.The accelerator can accumulate 250 nC of charge in 10 or more turns and extracted in one turn for transient mode experiment (15J). Debunch in 1 revolution

8. Note that a large compaction factor is necessary for achieving de-bunching for the electron beams in a single path! DBA ε=7.8nm α c =0.15

9. Effect of the gradient damping wigglers

10. Location of Bumpers

11. Dynamic Aperture

12. Emittance and damping time!

13. Vacuum Emittances are dominated by pressure in low energy, become natural emittances at high energy.

14. Touschek lifetime  Toucheck lifetime is sensitive to the parameter: is the rf bucket height, is the horizontal momentum spread can range from 0.001 to 1.  we will need a lifetime of 1h or more. It can also be varied by changing the momentum compaction factor

15. In summary, the ALPHA-project includes: I: Put back CIS with 2 electrostatic kickers and one Lambertson magnet, install a surplus linac to demonstrate the single-turn injection and extraction scheme. II: Refurbish and Install CIS cavity. Construct and install damping wigglers to verify the momentum compaction factor tuning and 10 or more turn accumulation! Commissioning the storage ring. III: Build an injector LINAC for beam injection into the storage ring. In the future, one can Move CRANE Linac to IUCF for high intensity beam commissioning. For eCIS design, the technology is well understood! The goal for the CRANE radiation effect experiments can easily be met! For the Compact Photon Source, the technology of 100 MW laser is available! IV: 90MHz cavity for photon source development, Design of Laser system, Optimization of Laser-beam interaction, photon flux and brilliance.

16. Accelerator Physics research with the ALPHA storage ring: 1.Quasi-isochronous accelerator beam dynamics (1 st and 2 nd order compaction factors) 2.Touschek Lifetime 3.Nonlinear beam dynamics 4.CSR 5.X-ray: Electron beams in an infinitely long linac (α c =0), encountering infinitely long weak undulators. What will be the electron beam distribution?