gamma beam systems a simple introduction. purpose of the machine deliver a high performance photon...
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Gamma Beam Systems
a simple introduction
![Page 2: Gamma Beam Systems a simple introduction. Purpose of the machine Deliver a high performance photon beam: Variable energy Highly polarized High intensity](https://reader030.vdocument.in/reader030/viewer/2022032705/56649dbd5503460f94ab00cc/html5/thumbnails/2.jpg)
Purpose of the machine
Deliver a high performance photon beam:• Variable energy• Highly polarized• High intensity• Low bandwidth
![Page 3: Gamma Beam Systems a simple introduction. Purpose of the machine Deliver a high performance photon beam: Variable energy Highly polarized High intensity](https://reader030.vdocument.in/reader030/viewer/2022032705/56649dbd5503460f94ab00cc/html5/thumbnails/3.jpg)
Where photons come from?Scattering of photons on high energy electrons.
What is the photon energy after scattering?
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Where photons come from?Scattering of photons on high energy electrons.
What is the photon energy after scattering?
24photonEMeV
Ee511.0
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Example
)520(5.2 greennmeVE f )500(1000 MeVEe
MeVEg 10
24photonE
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High correlation: photon energy and photon direction
Scattering in the direction of the electron
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Purpose of the machine
Deliver a high performance photon beam:• Variable energy: variable energy of the
electron beam• Highly polarized• High intensity• Low bandwidth
![Page 8: Gamma Beam Systems a simple introduction. Purpose of the machine Deliver a high performance photon beam: Variable energy Highly polarized High intensity](https://reader030.vdocument.in/reader030/viewer/2022032705/56649dbd5503460f94ab00cc/html5/thumbnails/8.jpg)
Purpose of the machine
Deliver a high performance photon beam:• Variable energy: variable energy of the
electron beam– Large energy range - > magnetic machine
• Highly polarized• High intensity• Low bandwidth
![Page 9: Gamma Beam Systems a simple introduction. Purpose of the machine Deliver a high performance photon beam: Variable energy Highly polarized High intensity](https://reader030.vdocument.in/reader030/viewer/2022032705/56649dbd5503460f94ab00cc/html5/thumbnails/9.jpg)
Purpose of the machine
Deliver a high performance photon beam:• Variable energy: variable energy of the
electron beam• Highly polarized: Compton scattering retains
the polarization of the laser photon• High intensity• Low bandwidth
![Page 10: Gamma Beam Systems a simple introduction. Purpose of the machine Deliver a high performance photon beam: Variable energy Highly polarized High intensity](https://reader030.vdocument.in/reader030/viewer/2022032705/56649dbd5503460f94ab00cc/html5/thumbnails/10.jpg)
Purpose of the machine
Deliver a high performance photon beam:• Variable energy• Highly polarized• High intensity: from intense photon and
electron beams• Low bandwidth
![Page 11: Gamma Beam Systems a simple introduction. Purpose of the machine Deliver a high performance photon beam: Variable energy Highly polarized High intensity](https://reader030.vdocument.in/reader030/viewer/2022032705/56649dbd5503460f94ab00cc/html5/thumbnails/11.jpg)
electrons laser
High intensity photon beam
•Many photons -> High intensity laser
•Many electrons ->High charge electron bunches
•Large overlap between photons and electrons
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Purpose of the machine
Deliver a high performance photon beam:• Variable energy• Highly polarized• High intensity: from intense photon and
electron beams• Low bandwidth: from collimation of photons
– We retain 0.1% of the photons after collimation
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Principle of operation of GBS
1. Electron bunches generated at photocathode2. Electron bunches transported to Interaction
Point – acceleration– focusing
3. Laser transported to interaction point4. Electron-Photon interaction5. Collimation of photons6. Experiments
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Why is it a complicated machine?
• Interaction laser– High intensity = low repetition rate (100 Hz) ->
recirculator to artificially increase the frequency
Recirculator: gives the time structure of the beam (1ns = 30 cm)
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Why is it a complicated machine?
• High charge electron bunches(250 pC):– High space charge effects
leads to high emittance (size of beam) ----
--- --
•Low bandwidth needs very low emittance:• size of beam at interaction point• direction of photon given by direction of
electron
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Why is it a complicated machine?
• Beam time structure:– Complex recirculator– Complex cathode laser– Complex synchronisation– Wakefields in RF cavities– Complicated electron beam diagnostics– Complicated photon beam diagnostics
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Gamma Beam System – Layout
e– RF LINACLow Energy
300 MeV
Interaction LaserLow Energy
Photo–drive Lasere– source
Interaction PointLow Energy
Photogunmultibunch
e– beam dump
g beam coll&diag
e– beam dump
Low Energy StageGamma rays up to 3.5 MeV
ControlRoom
RacksRoom
RacksRoom
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Gamma Beam System – Layout
e– RF LINACHigh Energy
720 MeV
Interaction LaserHigh Energy
Interaction LaserLow Energy
Photo–drive Lasere– source
Interaction PointHigh Energy
Photogunmultibunch
e– beam dump
g beam coll&diag
e– beam dump
High Energy StageGamma rays up to 19.5 MeV
ControlRoom
RacksRoom
RacksRoom
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Gamma Beam System – Layout
e– RF LINACLow Energy
300 MeV
Interaction LaserHigh Energy
Interaction LaserLow Energy
Photo–drive Lasere– source
Master clock synchronization @ < 0.5 ps
Interaction PointHigh Energy
Interaction PointLow Energy
Photogunmultibunch
e– beam dump
e– beam dump
g beam coll&diag
g beam coll&diag
e– beam dump
ControlRoom
RacksRoom
RacksRoom
e– RF LINACHigh Energy
720 MeV