Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.
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Transcript of Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.
![Page 1: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/1.jpg)
Non-invasive profile monitors for energy-frontier machines
Adam JeffCERN & University of Liverpool
![Page 2: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/2.jpg)
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Motivation
• Beam profile measurements are crucial for understanding new machines• Wire scanners, screens limited to pilot beams due to material damage
and losses caused• Non-intercepting monitors needed for online beam size measurement• Techniques exist but will be pushed to the limit…
Future challenges
• Future Circular Collider
• CLIC drive beam• High-Lumi LHC
Imaging techniques
• Synchrotron radiation
• Gas ionisation & fluorescence
• Vertexing
Scanning techniques
• Laser-wire• Electron-beam
scanner• Gas jet scanner
![Page 3: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/3.jpg)
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Motivation
• Beam profile measurements are crucial for understanding new machines• Wire scanners, screens limited to pilot beams due to material damage
and losses caused• Non-intercepting monitors needed for online beam size measurement• Techniques exist but will be pushed to the limit…
Future challenges
• Future Circular Collider
• CLIC drive beam• High-Lumi LHC
Imaging techniques
• Synchrotron radiation
• Gas ionisation & fluorescence
• Vertexing
Scanning techniques
• Laser-wire• Electron-beam
scanner• Gas jet scanner
![Page 4: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/4.jpg)
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ture
Circ
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Future Circular Collider• Proton beams at up to 100 TeV and leptons at Top & Higgs energies• Synchrotron with 100 km circumference, field strength 2xLHC dipoles• Challenges: High stored energy, low loss tolerance, small beam size…
![Page 5: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/5.jpg)
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hCL
IC D
rive
Beam
CLIC Drive Beam• Two-beam acceleration scheme demonstrated at CTF3
2.4 GeV
1.5 TeV
CLIC• Two-beam acceleration scheme demonstrated at CTF3• High intensity in drive beam: 100 A peak current• Requires non-intercepting profile measurement
![Page 6: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/6.jpg)
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High-Lumi LHC• Halo particles become important• Needs high-dynamic-range profile measurement• Hollow electron lenses for halo cleaning – need dedicated diagnostics
~4mm
![Page 7: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/7.jpg)
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am.je
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Motivation
• Beam profile measurements are crucial for understanding new machines• Wire scanners, screens limited to pilot beams due to material damage
and losses caused• Non-intercepting monitors needed for online beam size measurement• Techniques exist but will be pushed to the limit…
Future challenges
• Future Circular Collider
• CLIC drive beam• High-Lumi LHC
Imaging techniques
• Synchrotron radiation
• Gas ionisation & fluorescence
• Vertexing
Scanning techniques
• Laser-wire• Electron-beam
scanner• Gas jet scanner
![Page 8: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/8.jpg)
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• FCC would produce lots of visible synchrotron light at all energies, even with protons
• At top energy, plenty of x-rays too
Synchrotron Radiation spectra for protons in FCC dipoles
![Page 9: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/9.jpg)
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• Reduce diffraction by moving to shorter wavelengths• Many techniques from synchrotron light sources available
Pinhole Camera Fresnel Zone Plate
Compound Refractive Lens
![Page 10: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/10.jpg)
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am.je
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S
ynch
rotr
on R
adia
tion • Need to separate SR from particle beam
• Large bending radius means long distance (>100m)
dipole
beam
SR fan
SR monitor
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𝐷𝑜𝐹 ≈𝜌𝛾
∆ 𝑥 ≈𝜌𝛾 21
𝛾
1𝛾
FCC-hh DoF Δx
Injection 3 m 850 μm
Top Energy 0.2 m 4 μm• Can get round this by using a
dedicated undulator• LHC undulator would produce
soft x-rays
SR monitor
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• Background due to ionisation / excitation by synchrotron radiation
• Space charge effects distort profile measurement• Need strong magnet to
constrain ions• Fast measurement if additional
gas injected
• Space charge not a problem if neutral excited line chosen
• ‘Simple’ installation• Smaller cross-section
• Higher pressure or long integration
Thanks to P. Forck, GSI
Ionisation Profile Monitor Beam Fluorescence Monitor
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• Injection of a curtain-like gas jet through the beam pipe allows beam cross-section to be imaged
• Pressure is locally much higher -> stronger, faster signal• Jet can be collected on opposite side of beam pipe – relatively little
leakage to vacuum system.• Gas jet should be collimated, homogeneous and as thin as possible.
Details in next talk!
![Page 14: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/14.jpg)
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• New technique based on inelastic scattering between beam and rest gas• Several tracks are reconstructed for each event & vertex is located• Vertices are collected over many turns to image beam
Thanks to P. Hopchev, CERN
Scintillating-fiber detectors
Reduced aperture Thin end wall
Gas volume
![Page 15: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/15.jpg)
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am.je
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Motivation
• Beam profile measurements are crucial for understanding new machines• Wire scanners, screens limited to pilot beams due to material damage
and losses caused• Non-intercepting monitors needed for online beam size measurement• Techniques exist but will be pushed to the limit…
Future challenges
• Future Circular Collider
• CLIC drive beam• High-Lumi LHC
Imaging techniques
• Synchrotron radiation
• Gas ionisation & fluorescence
• Vertexing
Scanning techniques
• Laser-wire• Electron-beam
scanner• Gas jet scanner
![Page 16: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/16.jpg)
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L. Nevay, RHUL
• Scan laser beam and detect high-energy photons from inverse Compton scattering
• Proven method for measurement of very small electron beams• Proton cross-section is 6 orders of magnitude smaller
• Need to separate photons from beam and distinguish from SR• Could detect decelerated electrons instead
![Page 17: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/17.jpg)
17
W. Blokland, ORNL
adam
.jeff@
cern
.ch
El
ectr
on-B
eam
Sca
nner
• The ‘probe’ beam of electrons is deflected by the E-field of the main beam. The deflection depends on where the probe beam passes through the main beam.
• Using a diagonal curtain of electrons allows the profile to be measured in a single shot.
• Has been demonstrated for (quasi-)DC beams – analysis more complicated with short bunches.
Accelerator beam
Probe beam
![Page 18: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/18.jpg)
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• ‘Atomic Sieve’ to focus neutral gas jet based on de Broglie wavelength• Now being tested at Cockcroft Institute
• Generate a thin pencil jet and scan it through the beam• Like a wire scanner but non-interceptive• Readout by ion counting, fluorescence, bremsstrahlung, or beam losses• Not affected by space charge as position given by gas jet• Need a way to generate a thin jet…
![Page 19: Non-invasive profile monitors for energy-frontier machines Adam Jeff CERN & University of Liverpool.](https://reader036.fdocuments.net/reader036/viewer/2022062517/56649f325503460f94c4de68/html5/thumbnails/19.jpg)
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• Profile measurements at future energy-frontier machines will be challenging due to high intensity & small beam size.
• Exotic animals like electron lenses need unique solutions.
• Existing non-invasive techniques will be useful but cannot answer all the challenges– Synchrotron radiation difficult with v. large radius– Beam-gas ionisation limited by space charge
• Novel techniques such as beam gas vertexing and the gas jet scanner are promising, and will be tested soon at CERN and the Cockcroft Institute respectively.
Conclusions
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Thank you for your Attention
• Synchrotron Light at the LHC
• Design and performance of the upgraded LHC synchrotron light monitor, A. Goldblatt, E. Bravin, F. Roncarolo, G. Trad, Proc. IBIC (2013)
• X-ray imaging
• Beam diagnostics with synchrotron radiation in light sources, S. Takano, Proc. IPAC (2010)
• Beam Gas Ionisation & Fluorescence
• Minimal invasive beam profile monitors for high intense hadron beams, P. Forck, Proc. IPAC (2010)
• The first experience with LHC Beam Gas Ionisation Monitor, M. Sapinski et al., Proc. IBIC (2012)
• Beam Gas Vertexing
• A Beam Gas Vertex Detector for Beam Size Measurement in the LHC, P. Hopchev et al., Proc. IPAC (2014)
• Laser-wire
• Laserwire at the Accelerator Test Facility 2 with submicrometer resolution, L. J. Nevay et al., Phys. Rev. ST Accel. Beams 17 (2014)
• E-beam scanner
• Electron scanner for SNS ring profile measurements, W. Blokland, S. Aleksandrov, S. Cousineau, D. Malyutin, S. Starostenko, Proc. DIPAC (2009)
• Gas Jet scanner
• A quantum gas jet for non-invasive beam profile measurement, A. Jeff, E.B. Holzer, T. Lefèvre, V. Tzoganis, C.P. Welsch, H. Zhang, Proc. IBIC (2014)
• Other
• La dieta del cucurucho, A. Benot Morel (2015)