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Euclid Techlabs/Euclid Beamlabs

Euclid Techlabs, LLC is a research and development company specializing in linear particle accelerators, ultrafast electron microscopy, and advanced material technologies. The company was formed in 2003. Euclid Beamlabs LLC, formed in the winter of 2014, is a sister (spin-off) company of Euclid Techlabs LLC, particularly to commercialize industrial accelerator and related advanced material technologies developed at Euclid Techlabs. Euclid has developed expertise and products in several innovative technologies: time-resolved ultra-fast electron microscopy; ultra-compact linear accelerators; electron guns with thermionic, field emission or photo-emission cathodes; fast tuners for SRF cavities; advanced dielectric materials; HPHT and CVD diamond growth and applications; thin-film for accelerator technologies; Present: 27 people research staff (researchers, engineers, technicians) and 5 administrative. 16 PhDs in accelerator physics and material science, 32 staff. 2 labs: Bolingbrook, IL (accelerator R&D lab) and Beltsville, MD (material science lab). Long term collaborations with National Labs and Institutes: ANL, Fermilab, BNL, Jlab, LBL, SLAC, LANL, NIST, NIU, IIT, etc.

www.euclidtechlabs.com

Fermilab

Euclid

Argonne

Euclid

UMD

NRL, JLab

NIST

BNL

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Products & Capabilities Snapshot

Products

UltraFast Pulser (UFP^TM) for TEM
Dislocation free diamond for Xray optics
Compact X-Ray Source
NCRF and SRF electron sources
Low loss ceramics (linear and non-linear)
LINAC
RF window
In flange BPM

Capabilities

Femtosecond Laser Ablation System
Thin Film Deposition Lab
EM Testing Lab
Radiation Shielding/Testing Lab

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[1] I. V. Bazarov et. al., Phys. Rev. Lett. 102, 104801 (2009).

[2] A. Grudiev et. al., Phys. Rev. ST-AB, 12, 102001 (2009).

Our approach to high brightness

9 ns, 300 MW

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RF Gun Design

11.7 GHz field structure (Q≈200)

0-mode

11.7 GHz field structure at axis for 100 MW of incident power

π-mode

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High-Gradient Test and Beam Energy Characterization

~3% fluctuation

1000 shots as total

Energy measured by the spectrometer dipole
~3% fluctuation, likely due to the drive charge instability.
Max achieved gradient is 388 MV/m from the beam energy measurement

Simulated kinetic-energy isoclines as function of RF gun operating conditions K(E₀, φ₀) and retrieved operating points (“+” symbols). The shaded areas represent the uncertainty on the measured φ₀ and inferred E₀ values.

For details see the next talk by Chen Gongxiaohui (AWA).

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Developed RF design (2,5 cells)

Cathode

Backing solenoid

Solenoid

RF coupler

E-field at gun’s axis

TEM

1) RF coupler interferes to place solenoid close to the cathode.

2) RF coupler provides much more freedom.

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3,5 cell RF Design

Field balance is more vulnerable to size tolerance in comparison with 2,5 cell design.

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11.7 GHz RF Gun with Strongly Coupled Cells on π-Mode

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Advantages:

1. High-gradients and fully symmetric RF field distribution to minimize emittance;

2. Strong side coupling, in order to provide excellent field flatness, necessary mode separation and suppression of HOMs (for open version);

3. Design allows easy laser beam access to cathode and easy fine tuning;

4. Brazeless design and removable cathode.

Disadvantages:

Larger transverse size;
In case of open design some RF power can penetrate outside of gun.

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E-field distribution at gun’s axis

S₁₁, S₁₂ and S₁₃ parameters

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3,5 Cell Gun

E-field at axis

S₁₁ vs frequency

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Brazeless engineering design of 2,5 cell gun

Stainless steel

Copper

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Fully closed 11.7 GHz RF design

S₁₁ vs frequency

E-field at axis

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Coupler Designs

“Classical” design

Designs based on superinduced field asymmetry

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1. A. D. Cahill et al. High gradient experiments with X-band cryogenic copper accelerating cavities, 2018.

A Short Pulse Gun at Cryogenic Temperatures

Breakdown rate vs gradient[1]

For the 11.7 GHz 9 ns gun the cathode gradient at 45 K could be as high as more than 500 MV/m, maximum surface electric field might be as high as 750 MV/m.

2. V.A. Dolgashev, Recent High Gradient Tests at SLAC, 2016.

Peak pulse heating is a reasonably good predictor of the breakdown probability [2].

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Conclusion

We have plans to modify current RF design of the short pulse 11.7 GHz photoinjector at AWA to increase energy gain, reduce emittance, and to improve compatibility with the solenoid.
Alternatively, we can be focused on a new design based on strongly coupled rectangular cross-section cells. This flexible new design promises lots of benefits.
An additional opportunity to increase the gradient substantially is to operate a short pulse gun at cryogenic temperatures. AWA facility is an excellent test site to achieve a new high gradient world record.