INVENTORS:

Cary Yoshikawa, Ph.D.

David Johnson, Ph.D.

Charles Ankenbrandt, Ph.D.

and

Al Dudas, Ph.D.

J. Cross-Reference to Related Application

[0001] This application claims the benefit of U.S. Provisional Patent Application No.

61/536,589, filed September 20, 2011, which is hereby incorporated by reference in its entirety, as if set out below.

//. Field of the Disclosure

[0002] The present disclosure is generally related to enabling proton storage rings and

synchrotron accelerators to deliver multiple megawatts (MW) of beam power and, in particular, to injecting a substantial plurality of turns from a negative hydrogen ion (H ) linear accelerator (linac).

///. Summary

[0003] In a particular embodiment, a device is disclosed that includes means for injecting a substantial plurality of turns from a negative hydrogen ion (H ) linear accelerator (linac). The device also includes means for enabling proton storage rings and synchrotron accelerators to deliver multiple megawatts (MW) of beam power.

[0004] In another particular embodiment, a method is disclosed that includes steps for injecting a substantial plurality of turns from a negative hydrogen ion (H ) linear accelerator (linac). The method also includes steps for enabling proton storage rings and

synchrotron accelerators to deliver multiple megawatts (MW) of beam power. IV. Brief Description of the Drawings

[0005] The following figures form part of the present specification and are included to further demonstrate certain aspects of the present invention. The present invention may be better understood by reference to one or more of these drawings in combination with the description of embodiments presented herein.

[0006] Consequently, a more complete understanding of the present disclosure and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which the leftmost significant digit(s) in the reference numerals denote(s) the first figure in which the respective reference numerals appear, wherein:

[0007] Figure 1 is a diagram illustrating the beam power landscape for proton accelerator facilities;

[0008] Figure 2 is a diagram illustrating peak temperature in a carbon stripping foil for some particular Project X scenarios;

[0009] Figure 3 is a diagram illustrating the concept for using a rotating foil for multi-turn injection;

[0010] Figure 4 is a diagram illustrating an embodiment of an apparatus including means for injecting a substantial plurality of turns from a negative hydrogen ion (H ) linear accelerator (linac) and means for enabling proton storage rings and synchrotron accelerators to deliver multiple megawatts (MW) of beam power; and

[0011] Figure 5 is a flow diagram of an illustrative embodiment of a method including steps for injecting a substantial plurality of turns from a negative hydrogen ion (H ) linear accelerator (linac) and steps for enabling proton storage rings and synchrotron accelerators to deliver multiple megawatts (MW) of beam power.

V. Detailed Description

[0012] Illustrative embodiments of the present invention are described in detail below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of the present disclosure.

[0013] Particular embodiments of the present disclosure are described with reference to the drawings. In the description, common features are designated by common reference numbers.

[0014] Referring to Figure 1 , a diagram illustrating the beam power landscape for proton

accelerator facilities is depicted and indicated generally, for example, at 100.

[0015] Referring to Figure 2, a diagram illustrating peak temperature in a carbon stripping foil for some particular Project X scenarios is depicted and indicated generally, for example, at 200.

[0016] Referring to Figure 3, a diagram illustrating the concept for using a rotating foil for multi-turn injection is depicted and indicated generally, for example, at 300.

[0017] Referring to Figure 4, a diagram illustrating an embodiment of an apparatus is depicted and indicated generally, for example, at 400. The apparatus 400 includes means for designing 410 and means for simulating 420 a complete muon collider cooling channel.

[0018] Referring to Figure 5, a flow diagram of an illustrative embodiment of a method is depicted and indicated generally, for example, at 500. The method 500 includes steps for designing 510 and steps for simulating 520 a complete muon collider cooling channel.

[0019] Attached herewith as an Appendix to this specification are portions of an SBIR/STTR grant application entitled "H- STRIPPING INNOVATIONS FOR MULTI-TURN INJECTION," by Dr. Cary Yoshikawa, Dr. David Johnson, Dr. Charles Ankenbrandt, and Dr. Al Dudas, which is incorporated by reference as if set forth below. More details about various illustrative embodiments may be found by referring to the Appendix. [0020] The present invention is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as those that are inherent therein. While the present invention has been depicted, described and is defined by reference to exemplary embodiments of the present invention, such a reference does not imply a limitation of the present invention, and no such limitation is to be inferred. The present invention is capable of considerable modification, alteration, and equivalency in form and function as will occur to those of ordinary skill in the pertinent arts having the benefit of this disclosure. The depicted and described embodiments of the present invention are exemplary only and are not exhaustive of the scope of the present invention.

Consequently, the present invention is intended to be limited only by the spirit and scope of the appended claims, giving full cognizance to equivalents in all respects.

[0021] The particular embodiments disclosed above are illustrative only, as the present

invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of composition or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and intent of the present invention. In particular, every range of values (of the form, "from about a to about b," or, equivalently, "from approximately a to b," or, equivalently, "from approximately a-b") disclosed herein is to be understood as referring to the power set (the set of all subsets) of the respective range of values, in the sense of Georg Cantor. Accordingly, the protection sought herein is as set forth in the claims below.

[0022] The particular embodiments of the present invention described herein are merely

exemplary and are not intended to limit the scope of this present invention. Many variations and modifications may be made without departing from the intent and scope of the present invention. Applicants intend that all such modifications and variations are to be included within the scope of the present invention as defined in the appended claims and their equivalents.

[0023] While the present invention has been illustrated by a description of various

embodiments and while these embodiments have been described in considerable detail, it is not the intention of the Applicants to restrict, or any way limit the scope of the appended claims to such detail. The present invention in its broader aspects is therefore not limited to the specific details, representative apparatus, methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of Applicants' general inventive concept.

Phase I-SBIR/STTR Fiscal Year 2012 (Release 1)

NAME of PRINCIPAL INVESTIGATOR: Dr. Car Y. YosWkawa PHONE NUMBER: (630) 840-6314

TOPIC: 27a

PROJECT TITLE: H ^" Stripping Innovations for Multi-turn Injection

TECHNICAL ABSTRACT

STATEMENT OF THE PROBLEM OR SITUATION THAT IS BEING ADDRESSED.

Storage rings and synchrotrons intended to deliver very intense proton beams require injection systems that facilitate the accumulation of many turns of beam from an H ^" linac. The present state of the art has allowed injection of beams providing as much as about a megawatt of beam power; the next generation of facilities that aims to deliver several megawatts will require injection of many more turns.

GENERAL STATEMENT OF HOW THIS PROBLEM OR SITUATION IS BEING ADDRESSED.

New methods to advance the state of the art of multi-turn H ^" injection into rings by means of stripping foils are being developed in support of applications that require several megawatts of proton beam power delivered from synchrotrons or storage rings. Innovative methods will be incorporated into a coherent design for a complete injection system and simulated, and components for the most promising approaches will be prototyped and tested.

WHAT WILL BE DONE ΓΝ PHASE I.

Innovative ideas now at the preliminary conceptual design stage for multi-turn injection will be developed into more detailed conceptual designs. Injection systems incorporating these concepts will be simulated to establish feasibility. Engineering design of promising subsystems will commence and systems integration issues will be explored.

COMMERCIAL APPLICATIONS AND OTHER BENEFrrS

Methods to facilitate the delivery of megawatts of proton beam power will help make neutrino factories and muon colliders feasible for high energy physics while also enabling more intense spallation neutron sources for material science applications. Development of technically robust injection systems will enhance the feasibility and perhaps reduce the cost of operation of future facilities for high-energy physics and basic energy sciences. Development of new materials may benefit society in unimaginable ways.

KEY WORDS: multi-turn H ^" injection, stripping foil, storage ring, synchrotron

SUMMARY FOR MEMBERS OF CONGRESS:

Systems are being developed that will allow injection of very intense beams from linear accelerators into proton synchrotrons and storage rings. That capability will support many applications at the intensity frontier, including intense beams of neutrinos, muons, and neutrons for particle physics and material science applications. H ^" Stripping Innovations for Multi-turn Injection

Table of Contents a. Cover Page 1 b. Proprietary Data Legend - Not Applicable 2

Project Overview 3 c. Identification and Significance of the Problem or Opportunity, and Technical Approach 3

Identification and Significance of the Problem or Opportunity 3

Technical Approach 5 d. Anticipated Public Benefits 10 e. Technical Objectives 11 f. Phase I Work Plan 11

Responsibilities 11 g. Phase I Performance Schedule 11 h. Related Research or R&D 12 i. Principal Investigator and other Key Personnel 12 j. Facilities/Equipment 13 k. Consultants and Subcontractors 13

Appendix 1: Letter of Support from MAP 15

References 16 b. Proprietary Data Legend - Not Applicable

This proposal contains no proprietary data.

Project Overview

This project will evaluate three concepts to advance the technology of H stripping separately and as components of a coherent integrated injection system for purpose of accumulating protons over many turns from a linac into a proton storage ring or synchrotron. The techniques to be evaluated are multiple foils, rotating foils, and resonant foil bypass. The resulting technology will be useful for Project X, in particular, and any next generation facility that requires multi- megawatts of beam power. c. Identification and Significance of the Problem or Opportunity, and

Technical Approach

Identification and Significance of the Problem or Opportunity

There are many existing high-intensity proton sources worldwide for various applications, and several additional ones are in the planning stages. Figure 1, adapted from a slide prepared by Stuart Henderson, is a snapshot of the global beam power landscape. Average beam current is plotted vs. beam energy for present and possible future facilities. The red squares represent short- pulse facilities and the gray circles represent long-pulse facilities. Solid symbols stand for existing facilities and hollow symbols stand for planned facilities. The diagonal lines on the plot are lines of constant beam power. It is apparent that present facilities top out at about 1 MW of beam power, whereas plans for future facilities envision beams of several megawatts.

Figure 1: The beam power landscape for proton accelerator facilities. These facilities typically use linacs for part or all of the acceleration. Many of them also use synchrotrons, either storage rings or accelerators, to make shorter beam pulses and/or to reach higher energy than is practical directly from a linac. In those cases, a linac is normally used as an injector for the synchrotron. Since a linac typically produces a beam that is much longer than the circumference of the ring that it feeds, many turns must be injected, particularly in applications that require high beam power. H ^" stripping is the preferred method of injection in those cases.

The multi-turn injection is accomplished by stripping the electrons from the H ^" ions at the injection point. A common technique is to pass the H ^" to be injected through a thin stationary carbon or diamond foil to remove the electrons. Since this process allows injection of additional beam into already- occupied portions of phase space, it can result in a circulating proton beam that has higher phase space density than that of the linac beam. That is a fundamental advantage over conventional transverse or longitudinal stacking methods, which are limited by Liouville's theorem. However, in many cases the desired resulting transverse emittances in the synchrotron are much larger than the emittances of the H ^" ion beam to be injected. For example, larger transverse emittances are often necessary to mitigate space-charge effects. In those cases, a technique called transverse phase space painting is employed by varying the closed orbit in the synchrotron or the trajectory of the incoming beam during the injection process. Painting into the longitudinal phase space is also possible. The modern trend is to use superconducting linacs to accelerate the H ^" ions. Superconducting linacs allow delivery of long beam pulses, even CW beams in the limit, and user requirements and/or optimization of linac parameters often lead to the decision to deliver long beam pulses from the linac. That, in turn, requires development of techniques that allow injection and accumulation of very many turns into rings. That is the case for the facility known as Project X that is currently being planned for Fermilab. (This

SBIR/STTR proposal is targeted at the needs of Project X and uses that facility as its primary example; however, the techniques that we propose to develop should find wide applicability at other facilities.)

Project X is intended to provide three capabilities in support of the High Energy Physics mission of the US Department of Energy:

1. High-intensity, low-energy protons to provide kaon and muon beams for precision

measurements and experiments studying very rare processes;

2. A neutrino beam for long baseline neutrino oscillation experiments driven by a proton source that delivers at least 2 MW of beam power at any energy from 60 to 120 GeV;

3. A path toward a muon source for a possible future Neutrino Factory and/or a Muon

Collider. The Project X facility proposed to support those needs consists of the following:

1. A 3 GeV Superconducting RF (SCRF) Linac operating in continuous-wave (CW) mode and delivering an average beam current of 1 mA, corresponding to 3 MW of average beam power, feeding a 3 GeV Experimental Area;

2. A 3 to 8 GeV pulsed SCRF linac injecting into one of the existing Fermilab synchrotrons (the Recycler or Main Injector) for further acceleration by the Main Injector. Once in the (upgraded) Main Injector, the protons will be accelerated to a final energy in the range from 60 to 120 GeV and targeted on a neutrino production target with the beam power of at least 2 MW. (A word of explanation is in order at this point. The Recycler, a fixed- energy 8-GeV storage ring that uses permanent magnets, occupies the same tunnel as the Main Injector, a synchrotron that normally ramps from 8 GeV to 120 GeV. If a significant amount of time is needed for the injection process, then the Recycler will be used to accumulate beam while the Main Injector is ramping. If, on the other hand, the injection process can be accomplished quickly, beam from the linac can be injected directly into the Main Injector, bypassing the Recycler.)

3. The third element of the mission, a path toward a muon source for a Neutrino Factory and/or a Muon Collider, requires a linac upgrade path to 4 MW of beam power and storage rings to accumulate a relatively small number (-15 to 150) of beam bunches per second and shorten them before delivery to a pion production target.

Note that the second and third components of the program require accumulation of many turns from an FT linac into a ring. The first component, beams for precision kaon and muon experiments, may also require an accumulator ring if any of those experiments require proton beams having low duty factor.

In summary, intense proton beam synchrotrons currently being planned for future facilities, including Fermilab' s Project X, require more beam power and may be fed by lower linac beam currents than the present generation of facilities. Both of these trends require development of techniques for the injection of a much larger number of turns of beam from a linac into a synchrotron.

Technical Approach

There are two main approaches to multi-turn stripping injection of FT ions into proton synchrotrons: stripping foils and lasers. Stripping foils have been the workhorse of existing facilities, whereas laser-assisted stripping is "the new kid on the block" and may well be "the wave of the future".

The laser-assisted technique avoids the use of material in the beam, a considerable potential advantage. It involves electron photo-detachment through a three-step process [1] [2]. A proof of principle demonstration on a single 400-Mhz bunch has been performed at SNS using a narrow resonant laser process [3]. The laser-assisted stripping technique imposes considerable demands on the laser system: large pulse energies, high pulse frequencies, large macropulse lengths, and large average powers. The wavelength of the required laser field is dependent on the energy of the FT ion beam and the selected level of excitation of the neutral atom. For SNS the required laser wavelength is 355 nm, whereas for projects above 3.24 GeV the n=2 excited level may be reached using a more mature technology of lasers in the 1 μιη range [4] . Laser system

requirements for laser stripping at SNS are very stringent due to the required laser wavelength, and a complete solution does not exist today, though significant effort is being deployed to solve these issues. Laser system requirements for Project X are less stringent than those for SNS primarily due to the longer wavelength requirements, but the required peak and average power are significantly larger. R&D efforts toward a laser stripping system that might be utilized at Project X are just beginning.

We believe it is too early to "pick a winner" between the two technologies for stripping injection for future facilities, so that development of promising new approaches in both areas is warranted. The focus of this SBIR/STTR proposal is on further development of foil stripping techniques to meet the needs of Project X. In particular, the injection needs of the Main Injector will dominate the discussion because that is a capability that will certainly be needed as soon as Project X is operable.

The linac beam current, the beam pulse duration, and the number of "squirts" per injection cycle ultimately determine the amount of charge accumulated (and the resulting batch intensities) in the synchrotrons. To obtain a beam power of at least 2 MW at any energy from 60 to 120 GeV, it is necessary to inject a charge of about 26 mA-ms, i.e. 26 into the Recycler or the Main Injector. This corresponds to about 1.62xl0 ¹⁴ protons per cycle. The cycle time of the Main Injector ranges from about 0.75 sec at 60 GeV to about 1.2 sec at 120 GeV.

For large linac currents, corresponding to short injection times, the largest density of energy deposition on the foil occurs where the injected beam passes through it. Conversely, for small linac currents, corresponding to long injection times, the largest density of energy deposition occurs where the most circulating protons pass through the foil during the injection process. These subsequent interactions of circulating protons with the foil are commonly referred to as "parasitic" hits. They not only deposit energy in the foil via ionization energy losses, thus heating the foil, but also interact with the atoms in the foil through Coulomb scattering or nuclear interactions, increasing the emittances of the circulating beam and creating beam losses. The number of "parasitic" hits due to the circulating beam may be minimized through the choice of ring optics, injected and circulating beam emittances, and phase space painting parameters. The minimum number of parasitic hits [5] may be estimated by where N _t is the number of turns injected, ε is the injected beam transverse emittance, and A is the final transverse emittance painted into the ring. The number of turns injected is directly dependent on the linac current and hence the injection time. Depending on the size of the synchrotron, circulating protons may pass the foil thousands of times during the injection process. For example, with a revolution period of approximately 11 μ8 and an injection time of 26 ms, the first protons injected will make more than 2300 turns during the injection process.

Because the low-energy 3-GeV linac for Project X is CW, the average beam current available from the high-energy pulsed linac during the injection pulse for the Main Injector is likely to be limited to one or two mA. This implies long total injection times of 13 to 26 msec into the Recycler or Main Injector. If the whole required charge can be injected in a single "squirt", then the beam would be injected directly into the Main Injector; that is the preferred scenario.

Conversely, if several "squirts" are necessary at a repetition rate of order 10 Hz, then the

Recycler will be used as an accumulator, followed by single turn injection into the Main Injector (-11 μ8 duration). For example, one present injection concept utilizes the Recycler Ring as an accumulator, with the 26 ms of total injection time broken up into six injections, each with a duration of 4.3 ms. In this type of scenario, the circulating beam is moved away from the foil when the linac is not delivering beam, allowing the foil to cool down between "squirts". If the linac pulses at 10 Hz, the total injection time would be shorter than a Main Injector cycle.

For the practical application of charge exchange stripping, the lifetime of the carbon foil should be long, preferably at least thousands of hours. The lifetime of these foils under ion

bombardment is determined by radiation damage (defect generation rate), peak temperatures, strength characteristics of the foil material, migration energy of the displaced atoms and its dependence on the crystalline size, the conditions of fastening the foil on the frame, and oscillation frequency of the atoms in a crystalline structure [6].

The experience at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory has shown stripper foils under ion bombardment surviving with accumulated charge of more than 7500 Coulombs, with estimated peak temperatures in the 1500°K range. The integrity of the foil degrades rapidly if the temperature rises much higher. This practical experience gives us a benchmark on survivability of stripper foils. For Project X, the injected charge is 26 μC per injection at roughly a 1 Hz rate. Assuming a 100% duty factor and the parasitic hits/injected ion, hmin , to be 50 and keeping the peak foil temperature below 1500°K, a foil should last on the order of 60 days. The conclusion to be drawn is that peak foil temperatures are a critical factor affecting the foil lifetimes.

The peak temperature of the foil is governed by the rate of energy deposition density and the cooling due to blackbody radiation. The peak temperature as a function of time for a stationary foil is given by

where N is the "hit" density, p is the density of carbon, c(T) is the specific heat of carbon as a function of temperature, ε is the emissivity, o _sb is the Stephan-Boltzmann constant, and Δζ is the foil thickness. The energy deposition term, dE/dz, is modified to reflect the reduction in energy deposition in thin targets due to delta electrons escaping the foil. For 8 GeV protons on a 600 μg/cm foil, a simulation with MCNPX shows that approximately 28% of the ionization energy loss is taken away by the delta electrons that escape the foil, thus reducing the energy deposition. (On the other hand, short-range products of nuclear interactions increase the energy deposition somewhat.)

Figure 2 shows the result of the temperature calculation for some injection scenarios. Note that the time is plotted on a log scale. All the curves satisfy the requirement of 26 mA-ms of charge accumulated per MI cycle. The magenta curve represents a single 26 ms injection of a 1 mA linac beam. The other four curves represent injections at a 10 Hz rate, with 6 injections required per cycle, for different linac currents.

Tiiiie ( ^' msec)

Figure 2: Peak temperature in a carbon stripping foil for some particular Project X scenarios.

Two concepts for the reduction of the operating temperature of stripping foils have been described recently by Dr. Charles Ankenbrandt, the identified key person in this proposal, and his co-authors [7] :

1. Longitudinally Segmented Stripping Foils: The idea is to use multiple stripping foils in series in the beam direction. That takes advantage of the facts that the optimum stripping foil thickness for a multi-GeV beam is about 600 μg/cm and that foils that are 200 μg/cm thick have proven to be quite durable in normal Fermilab Booster operation. Thus the stripping foil can be segmented longitudinally into (say) 3 foils, so that there are six surfaces to dissipate the heat by radiation instead of two. The foils should be separated by enough distance so that the solid angle for interception of the blackbody radiation from an adjacent foil is a small fraction of 2π, and so that electrons emanating from a foil could be swept away by a weak magnetic field between the foils. In that case, a simple argument suggests that the peak temperature would be reduced by at least a factor of 3 ^1/4 It is worth noting that the use of at least two foils has been suggested in the past to mitigate the effects of any "pinholes" in the foils. Furthermore, the failure of one foil would not necessitate immediate corrective action, since 400 μg/cm would still be close to the optimum thickness.

2. Rotating Stripping Foils: The second idea is to rotate a circular foil rapidly, with an annulus having a radial extent of about 1 cm exposed in one corner of the aperture of the synchrotron. That will spread out the energy deposition over an effective area of several square cm. The concept is illustrated in Figure 3.

Disk Holder

Figure 3: Illustration of the concept for using a rotating foil for multi-turn injection.

While these two ideas promise to reduce the operating temperature of the foils, they do nothing to mitigate the other deleterious effects when the circulating beam passes repeatedly through the foils: emittance blowup, generation of transverse beam halo, and beam losses. For that purpose, it is necessary to reduce the number of foil hits by the circulating beam. A third idea contained in the aforementioned publication promises to help in that regard:

3. Resonant Foil Bypass: This new idea was originally presented at a workshop on Project- X muon beams at Fermilab by Dr. Charles Ankenbrandt, the identified key person in this proposal, and dubbed "resonant foil bypass" by the organizers of that parallel session. Basically, the idea is to move the circulating beam rapidly away from the foil when beam is not actually being injected. To accomplish that, two things happen synchronously: a) the incoming beam is modulated at a relatively high frequency (of order 1 MHz, high enough that the high-Q SRF cavities average over the gaps in the beam) using a nimble chopper at the front end of the linac, and b) the closed orbit at the foil is moved by high- frequency dipoles so that the circulating beam is closest to the foil only when the incoming beam is "on". In other words, the idea is to run the CW linac with pulsed beam, albeit beam that is pulsed at a high frequency. If the average current during the pulses is 10 mA and the macroscopic average current is 1 mA, then the probability of a circulating proton hitting the foil might be reduced by nearly an order of magnitude by this means. The front-end chopper and the values of 10 mA (peak current) and 1 mA (average current) used in the above example are an integral part of the planning for Project X. A detailed engineering design of high-frequency dipoles oscillating at ~1 MHz has recently been developed for another purpose at Fermilab [8].

To reiterate, the first application of these ideas may be to provide beam to the Main Injector in the Project X era. If long beam pulses from the linac can be injected directly into the Main Injector, bypassing the Recycler, the resulting complex will be considerably simplified. It is quite possible that that can be accomplished without employing all three of the new injection ideas described above. However, in the longer term, a more demanding application looms: injection into the accumulator ring for a Muon Collider front end and/or a Neutrino Factory. That application will be more demanding because the beam power is higher and the circumference of that ring will be considerably smaller than the Main Injector, though it will have a larger aperture to work with. So the motivation is strong to explore the ultimate limits of foil-based stripping injection for the Muon Collider application.

That, in a nutshell, is the gist of this proposal: to develop these three ideas, and any others that may arise in the process of carrying out this work, and incorporate some or all of them into the design of a system that establishes the feasibility of long-pulse injection into synchrotrons via stripping foils for multi-megawatt applications. d. Anticipated Public Benefits

The development of feasible systems for the injection of very many turns from an H ^" linac will enable the realization of proton storage rings and synchrotron accelerators that can deliver many megawatts of beam power. That in turn will enable the creation of major new facilities for particle physics and material science. Increasing the available beam power allows future facilities to collect data faster, reducing the cost of future experimental programs and providing useful results at a faster pace.

In High Energy Physics, the applications include neutrino superbeams derived from pion decays and intense muon beams for precision experiments, neutrino factories and muon colliders. A facility that provides a path back to the energy frontier is a compelling goal for the US high- energy-physics community; a collider that fits on an existing site is particularly attractive. In Basic Energy Science, the applications include more powerful spallation neutron sources.