4.  ANCILLARY TECHNOLOGIES FOR ACCELERATOR FACILITIES

 

The Office of Basic Energy Sciences, within the DOE’s Office of Science, is responsible for current and future synchrotron radiation light source, free electron laser, and spallation neutron source user facilities.  This topic seeks the development of computational, control, and superconducting technologies to support these user facilities.  Grant applications are sought only in the following subtopics.

 

a. Accelerator Modeling and Control—Grant applications are sought to develop new or improved computational tools for the design, study, or operation of charged particle beams.  Of particular interest is the development of a front-end design for user-friendly interfaces.  The modeling challenges addressed must be relevant to present and future BES accelerator facilities.  These challenges include, but are not limited to, beam halo generation and control; generation and synchronization of sub-ps x-ray pulses; wakefield computation; multiple and single bunch collective instabilities; electron cloud generation and effects, especially in high intensity proton rings; and high-intensity operation (beam losses, thermal effects, etc.)

 

Grant applications also are sought to investigate and develop enhancements to the suite of tools in the Experimental Physics and Industrial Control System (EPICS), in order to better support existing facilities and meet the requirements of future machines.  Areas of interest include, but are not limited to, high-availability alternative-communication protocols; enhanced functionality within the Input-Output Controller; highly integrated development environments; and ensuring scalability to very large installations (such as the International Linear Collider).  Grant applications should address how the results will guide long-term EPICS development.

 

As the time scale of interest in modern accelerators is reduced, the required computational resources are becoming prohibitive for currently-available low-order electromagnetic codes; for example, the estimated memory requirement for modeling a typical accelerator structure interacting with a 1-ps bunch is 1 TB.  Such an extreme computation is intractable for most accelerator laboratories.  Therefore, in order to break the computational bottleneck, grant applications are sought to develop computational electromagnetic codes with high-order accuracy.

 

Finally, grant applications are sought to develop large-scale timing and synchronization systems for next generation light sources, with timing stability requirements extending from ~100 fs to 1 femtosecond or less.  For example, these requirements include the need to enable the synchronization of multiple radio frequency components and laser systems, over distances of the scale of km, in advanced accelerators and free electron lasers.  This precision in timing must be maintained over periods of time on the order of 24 hours.

 

Questions - contact Roger Klaffky (roger.klaffky@science.doe.gov)

 

b. Superconducting Technology for Accelerators—Superconducting HOM-damped (higher-order-mode-damped) RF systems are needed for present and future storage ring and linac applications.  Grant applications are sought to develop:

 

(1) A high gradient (15-50 MVm-1) 750MHz superconducting cavity for linac-driven synchrotron radiation sources.  The cavity should operate in CW mode with high efficiency of wall-plug-to-beam-power conversion.  Systems should be capable of supporting a beam current up to 500 mA, with parasitic mode Q-values below 1000, and minimal short-range wakefields.

 

(2) A 1500 MHz passive superconducting Landau cavity for storage-ring bunch lengthening.

 

(3) A superconducting RF power coupler capable of handling 500 kW CW RF power. 

 

Questions - contact Roger Klaffky (roger.klaffky@science.doe.gov)

 

c. Cooling of Superconducting Systems—A fundamental conceptual issue has arisen concerning the cooling of superconducting linacs during high-power pulsed operation.  At fast pulse (1 ms), high-average forward-power levels (~ 75 kW), excessive thermal radiation loads from the fundamental couplers result in high couple surface temperatures, which reduce cavity stability and operating accelerating gradients. Therefore, grant applications are sought to develop innovative cooling concepts for fundamental power couplers, which do not impact the performance of the associated superconducting cavities.

 

In addition, with the successful implementation of superconducting radiofrequency accelerating structures at facilities in all regions of the world, additional emphasis is being placed on reducing superconducting radiofrequency (SRF) cryomodule costs and improving manufacturing quality. Therefore, grant applications are sought for innovative concepts and design approaches to the manufacture of cryomodule assemblies containing multiple-processed SRF cavities. Approaches of interest include new cavity cooling and support systems, reliable cavity tuners and tuner components, and less expensive fundamental couple assemblies. 

 

Questions - contact Roger Klaffky (roger.klaffky@science.doe.gov)

 

d. Advanced Laser Systems for Accelerator Applications—Advanced laser systems are needed for photoinjectors, for Free-Electron Laser Seeding or for current-enhanced self-amplified spontaneous emission (ESASE), for laser-ion stripping of hydrogen beams, and for laser wire beam profile measurements in proton particle accelerators.  Grant applications are sought for the development of:

 

(1) High power laser oscillator systems for high repetition rate (1-100 MHz) electron guns that can deliver pulses of 10-100 μJ energy in the 1 μm wavelength range, with pulses capable of being expanded to10-50 ps duration. 

 

(2) Laser pulse shaping systems that can modify the laser pulse in 3D, in order to minimize the emittance growth due to space charge effect in a photoinjector.  Approaches of interest can include pulse stacking, laser phase modulation, and others.  In general, the pulse should have a homogeneous intensity distribution (10% modulation) confined in a sharp boundary in 3D, with either a cylindrical or ellipsoidal geometry.

 

(3) A mid-IR, carrier envelope phase (CEP) stabilized laser with tens of mJs of energy and a few carrier cycles within a FWHM of 10-50 fs.

(4) A mid-IR (2.0 micron) laser for E-SASE, with a pulse under 100fs,  possibly CEP-stabilized in the few mJ energy range.

 

(5) Tunable lasers to be used as seeds for free electron lasers (FELs).  The central wavelength should be within the range of 10-50 nm, and continuously tunable within a 20% or greater band within that wavelength range.  Pulse duration should be adjustable and on order of 100 fs.  Peak power within the pulse should be on order of 100 kW.  Optical pulses should be reproducible on a shot-to-shot basis, with good temporal coherence within the pulse, good beam quality (M2<1.3), and a repetition rate of 100 kHz or greater.

 

(6) Lasers for laser-ion stripping of hydrogen beams with the following features:  high repetition rate (~400 MHz), high peak power (~1MW), picosecond 355 nm pulses to match the SNS linac in-beam structure (50 ps long micropulses separated by 2.5 ns and gated into minpulses of 650 ns repeating at 1.058 MHz and bunched into 1 ms macropulses).

(7) Laser power-recycling cavity at 355 nm to reduce average laser power requirements for ion stripping. Important design criteria include compactness, length to match bunch repetition rate and stabilized to small fraction of wavelength, protection of mirrors from electron and gamma radiation, and in vacuum design.

 

(8) Lasers for laser-wire-beam profile measurements with the following specifications:

 

·        pulse energy of 100 mJ at 1064 nm;

·        repetition rates of 30 or 60 Hz with external trigger;

·        compact laser head with dimension of about 6’x3”x3”;

·        no chilled water required;

·        power supply remotely controllable through Ethernet cables; and

·        radiation resistance for doses greated than 106 rads. 

 

Based on previous experiments, key components in the radiation-resistant laser system are the YAG crystal, fold prism, cube polarized in the laser head, and IC chips in the laser controller unit.

 

Questions - contact Roger Klaffky (roger.klaffky@science.doe.gov)

 

Subtopic a References

 

1.    Bisognano, J. J. and Mondelli, A. A., eds., Computational Accelerator Physics, Williamsburg, VA,

September 24-27, 1996, American Institute of Physics (AIP), May 1997. (AIP Conference Proceedings No.

 391) (ISBN: 1-56396-671-9)

2.   Qiang, J. and Ryne, R., “Parallel Beam Dynamics Simulation of Linear Accelerators,” Proceedings of ACES

2002: 18th Annual Review of Progress in Applied Computational Electromagnetics, Monterey, CA, March

18-22, 2002, January 31, 2002. (Report No. LBNL-49550) (Full text available at:

http://www.osti.gov/energycitations/servlets/purl/792968-2qDC1P/native/792968.pdf)

3.   Ko, K., “High Performance Computing in Accelerator Physics,” Proceedings of 18th Annual Review of

      Progress in Applied Computational Electromagnetics: ACES-2002, Monterey, CA, March 18-22, 2002.

      (Full text available at: http://www-group.slac.stanford.edu/acd/Computers2.html#)

4.   Ryne R., et al., “SciDAC Advances and Applications in Computational Beam Dynamics,” presented at

      SciDAC (Scientific Discovery Through Advanced Computing) 2005, San Francisco, June 26-30, 2005.

      (Full text available at: http://seesar.lbl.gov/anag/publications/colella/LBNL-58243.pdf)

5.   Proceedings of ICAP 2004--the International Computational Accelerator Physics Conference: St.

      Petersburg, Russia, June 2004, “Nuclear Instruments and Methods in Physics Research Section A:

      Accelerators, Spectrometers, Detectors and Associated Equipment,” 58(1), March 2006. (Abstracts and

      ordering information for papers available at: http://sciencedirect.com. One menu at left, Browse by journal

      title, above; then by volume and issue.)

6.  Proceedings of EPICS (Experimental Physics and Industrial Control System) Collaboration Meeting,

     Argonne, IL, June 2006. (Presentation slides available at:

     http://www.aps.anl.gov/News/Conferences/2006/EPICS/index.html. On menu at left click on

     “Presentations.” To view slides, click on titles.)

 

7.  R. B. Wilcox and J. W. Staples, "Synchronizing Lasers Over Fiber by Transmitting Continuous Waves", Conference on Lasers and Electro Optics 2007,     Baltimore MD, paper CThHH4 (2007).

 

8.   R. B. Wilcox and J. W. Staples, "Systems Design Concepts for Optical Synchronization in Accelerators", Particle Accelerator Conference 2007, Albuquerque,     NM, paper FROAC05 (2007).

 

9.   J. Kim, F. X. Kartner and F. Ludwig, "Balanced optical-microwave phase detectors for optoelectronic phase-locked loops", Opt. Lett. 31, 3659 (2006).

 

10. J. Kim, J. Chen, Z. Zhang, F. N. C. Wong, F. X. Kartner, F. Loehl, and H. Schlarb, "Long-term femtosecond timing link stabilization using a single-crystal  balanced cross correlator", Opt. Lett. 32, 1044 (2007).

 

11.  I. Coddington, W. C. Swann, L. Lorini, J. C. Bergquist, Y. Le Coq, C. W. Oates, Q. Quraishi, 12.K. S. Feder, J. W. Nicholson, P. S. Westbrook, S. A. Diddams and N. R. Newbury, "Coherent optical link over hundreds of metres and hundreds of terahertz with subfemtosecond timing jitter", Nature Photonics 1, 283 (2007).

 

12  .Darren D. Hudson, Seth M. Foreman, Steven T. Cundiff, and Jun Ye, "Synchronization of mode-locked femtosecond lasers through a fiber link", Opt. Lett. 31, 1951 (2006).

 

Subtopic b References:

 

 1.  Latest developments  in superconducting rf structures for beta=1 particle acceleration, P. Kneisel, Proc. EPAC06, Edinburgh, June 2006,  http://accelconf.web.cern.ch/AccelConf/e06/Pre-Press/WEXPA01.pdf

2.  Review of Various Approaches to Address High Currents in SRF Electron Linacs, I. Ben-Zvi, http://www.lns.cornell.edu/public/SRF2005/pdfs/ThA03.pdf

 

Subtopic c References:

 

1.  Schneider, W. J., et al., “Design of the SNS Cryomodule,” Proceedings of the 2001 Particle Accelerator

     Conference, Chicago, IL, June 2001. (Full text available at: http://www.jlab.org/. On menu at left click on

 

Subtopic d References:

 

 1.  V. Danilov et al, “Proof-of-principle demonstration of  high efficiency laser-assisted H- beam conversion to protons”, Phys. Rev. ST Accel. Beams 10, 053501 (2007).

2.   S. Assadi et al, “The SNS laser profile monitor design and implementation” Proc. PAC 2003, Portland, USA, p. 2706; Y. Liu et al, “Laser wire beam profile monitor at SNS”, TUPC061, Proc. EPAC 2008, Genoa, Italy.

3.  W. P. Leemans, “GeV electron beams from a centimetre-scale accelerator,” Nature Physics 2, 696-699 (2006).

4.  A. Noda et al., “Recent status of laser cooling of Mg realized at S-LSR,” THPP050, Proc. EPAC 2008, Genoa, Italy.

5.  I. Will, G. Koss, and I. Templin, “The upgraded photocathode laser of the TESLA Test Facility,” Nuclear Instruments and Methods in Physics Research A 541, 467-477 (2005).

 

6.  I. Will, G. Koss, and I. Templin, “The upgraded photocathode laser of the TESLA Test Facility,” Nuclear Instruments and Methods in Physics Research A 541, 467-477 (2005).

7.  U. Vogt, H. Stiel, I. Will, P.V. Nickles, T. Wilhein, M. Wieland, W. Sandner, SPIE Proc. 4343, 87 (2001).


8.  Zhirong Huang and Ronald D. Ruth, “Laser-electron storage ring,” Phys. Rev. Lett. 80, 976-979 (1998).

9.   E. Bulyak et al., “Compact X-ray source based on Compton backscattering,” Nuclear Instruments and Methods in Physics Research A 487, 241-248 (2002).

10. E. O. Potma et al, “Picosecond-pulse amplification with an external passive optical cavity,” Opt. Lett. 28, 1835-1837 (2003).

11. M. Nomura et al., “Enhancement of laser power from a mode lock laser with an optical cavity,” Proc. EPAC 2004, 2637-2639.

12. H. Kumagai et al, “Efficient frequency doubling of 1-W continuous-wave Ti:sapphire laser with a robust high-finesse external cavity,” Appl. Opt. 42, 1036-1039 (2003).

13. E.G. Bessonov and R.M. Fechtchenko, “A composite open resonator for a compact X-ray source,” Nuclear Instruments and Methods in Physics Research  A 528, 212-214 (2004).

14. A.J. Rollason, X. Fang, D.E. Dugdale, “Multiple pass cavity for inverse Compton interactions,” Nuclear Instruments and Methods in Physics Research A 526, 560-571 (2004).

 15. S. M. Kaczmarek, “Influence of Ionizing Radiation on Performance of Nd:YAG Lasers,” Crystal Res. Technol. 34, 1183-1190 (1999).

16. T. S. Rose, M. S. Hopkins, and R. A. Fields, “Characterization and Control of Gamma
       and Proton Radiation Effects on the Performance of Nd : YAG and Nd : YLF Lasers,” IEEE J. Quantum Electron. 31, 1593-1602 (1995).