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{{Short description|Acceleration cavity module in modern particle accelerators}}
A '''cryomodule''' is that section, or sections of a [[linear particle accelerator]] composed of [[superconducting]] [[niobium]] cavities used in a [[linear accelerator]], or linac.
{{See also | Superconducting Radio Frequency }}
[[Image:SRF Cavity Diagram 1.png|thumb|Simplified sketch of a SRF [[microwave cavity|cavity]] in a helium bath, with [[Radio Frequency|RF]] coupling and a passing [[particle beam]].]]


The cryomodule is a complex, state-of-the-art supercooled component in which particle beams are accelerated for scientific research.
A '''cryomodule''' is a section of a modern [[particle accelerator]] composed of [[Superconducting Radio Frequency|superconducting RF]] (SRF) acceleration [[microwave cavity|cavities]], which need very low [[operating temperature]]s (often around 2 [[Kelvin]]). The cryomodule is a complex, state-of-the-art [[supercooled]] component in which particle beams are accelerated for scientific research. The [[superconducting]] cavities are cooled with [[liquid helium]].
The niobium cavities are cooled with [[liquid helium]] to an operating temperature of 2 Kelvin to supercool this section of the [[linear particle accelerator|accelerator]] specifically tuned for RF at the low temperatures.


The cryomodule section of the linac section is a [[superposition]] of normal conducting and [[superconducting]] radio-frequency cavities that accelerate the beam and a [[magnetic lattice]] that provides focusing and steering.
A cryomodule ''section'' of an accelerator is composed of superconducting cavities that accelerate the beam, also including a [[magnetic lattice (accelerator)|magnetic lattice]] that provides focusing and steering.

==Design considerations==

SRF cavities tend to be thin-walled structures immersed in a bath of liquid helium having temperatures of 1.6 [[Kelvin|K]] to 4.5 K. Careful engineering is required to insulate the helium bath from the room-temperature external environment. This is accomplished by:
* A vacuum chamber surrounding the cold components to eliminate [[Convection|convective]] heat transfer by gases.
* [[Multi-layer insulation]] wrapped around cold components. This insulation is composed of dozens of alternating layers of aluminized mylar and thin fiberglass sheet, which reflects infrared radiation that shines through the vacuum insulation from the 300 K exterior walls.
* Low [[thermal conductivity]] mechanical connections between the cold mass and the room temperature vacuum vessel. These connections are required, for example, to support the mass of the helium vessel inside the vacuum vessel and to connect the apertures in the SRF cavity to the accelerator beamline. Both types of connections transition from internal cryogenic temperatures to room temperature at the vacuum vessel boundary. The thermal conductivity of these parts is minimized by having small cross sectional area and being composed of low thermal conductivity material, such as stainless steel for the vacuum beampipe and fiber reinforced epoxies (G10) for mechanical support. The vacuum beampipe also requires good electrical conductivity on its interior surface to propagate the image currents of the beam, which is accomplished by about 100 μm of copper plating on the interior surface.

<gallery mode="packed" class="center">
File:International Linear Collider main linac cryomodule - exterior.jpg|A cryomodule of [[International Linear Collider]] being tested at [[Fermilab]]<ref>{{cite book|title=The International Linear Collider Technical Design Report 2013|date=2013|publisher=International Linear Collider|url=http://edmsdirect.desy.de/edmsdirect/file.jsp?edmsid=D00000001021265&fileClass=native|accessdate=14 August 2015}}</ref>
File:International Linear Collider main linac cryomodule - cross section.jpg|Cross section of the cryomodule. A large tube at the center is Helium gas return pipe. The closed tube below it is the beam axis.
File:International Linear Collider main linac cryomodule - flange.jpg|A flange of the cryomodule is used to connect instrumentation wires and cables.
File:A 1.3 GHz nine-cell superconducting radio frequency.JPG|An example of [[niobium]]-based 1.3&nbsp;GHz nine-cell [[superconducting radio frequency]] to be put along the beam axis inside the cryomodule
</gallery>

==References==
{{Reflist}}


==External links==
==External links==
* [http://www.jlab.org/div_dept/dir_off/public_affairs/news_releases/2003/03sns.html Cryomodules at Jefferson lab]
* [https://web.archive.org/web/20051027232246/http://www.jlab.org/div_dept/dir_off/public_affairs/news_releases/2003/03sns.html Cryomodules at Jefferson lab]
* [http://www.jlab.org/accel/survalign/documents/images/cryomod/thumbnails.html Cryomodule images]
* [http://www.jlab.org/accel/survalign/documents/images/cryomod/thumbnails.html Cryomodule images] {{Webarchive|url=https://web.archive.org/web/20050103185655/http://www.jlab.org/accel/survalign/documents/images/cryomod/thumbnails.html |date=2005-01-03 }}
⚫
* [http://www1.jlab.org/ul/Publications/documents/ACFA2B.pdf A Cryomodule performance (PDF)]{{dead link|date=August 2017 |bot=InternetArchiveBot |fix-attempted=yes }}

[[Category:Accelerator physics]]


⚫
* [http://www1.jlab.org/ul/Publications/documents/ACFA2B.pdf A Cryomodule performance]


{{Accelerator-stub}}
[[Category:Particle accelerators|Cryomodule]]

Latest revision as of 22:14, 22 August 2024

See also: Superconducting Radio Frequency
Simplified sketch of a SRF cavity in a helium bath, with RF coupling and a passing particle beam.

A cryomodule is a section of a modern particle accelerator composed of superconducting RF (SRF) acceleration cavities, which need very low operating temperatures (often around 2 Kelvin). The cryomodule is a complex, state-of-the-art supercooled component in which particle beams are accelerated for scientific research. The superconducting cavities are cooled with liquid helium.

A cryomodule section of an accelerator is composed of superconducting cavities that accelerate the beam, also including a magnetic lattice that provides focusing and steering.

Design considerations

[edit]

SRF cavities tend to be thin-walled structures immersed in a bath of liquid helium having temperatures of 1.6 K to 4.5 K. Careful engineering is required to insulate the helium bath from the room-temperature external environment. This is accomplished by:

  • A vacuum chamber surrounding the cold components to eliminate convective heat transfer by gases.
  • Multi-layer insulation wrapped around cold components. This insulation is composed of dozens of alternating layers of aluminized mylar and thin fiberglass sheet, which reflects infrared radiation that shines through the vacuum insulation from the 300 K exterior walls.
  • Low thermal conductivity mechanical connections between the cold mass and the room temperature vacuum vessel. These connections are required, for example, to support the mass of the helium vessel inside the vacuum vessel and to connect the apertures in the SRF cavity to the accelerator beamline. Both types of connections transition from internal cryogenic temperatures to room temperature at the vacuum vessel boundary. The thermal conductivity of these parts is minimized by having small cross sectional area and being composed of low thermal conductivity material, such as stainless steel for the vacuum beampipe and fiber reinforced epoxies (G10) for mechanical support. The vacuum beampipe also requires good electrical conductivity on its interior surface to propagate the image currents of the beam, which is accomplished by about 100 μm of copper plating on the interior surface.
  • A cryomodule of International Linear Collider being tested at Fermilab[1]
    A cryomodule of International Linear Collider being tested at Fermilab[1]
  • Cross section of the cryomodule. A large tube at the center is Helium gas return pipe. The closed tube below it is the beam axis.
    Cross section of the cryomodule. A large tube at the center is Helium gas return pipe. The closed tube below it is the beam axis.
  • A flange of the cryomodule is used to connect instrumentation wires and cables.
    A flange of the cryomodule is used to connect instrumentation wires and cables.
  • An example of niobium-based 1.3 GHz nine-cell superconducting radio frequency to be put along the beam axis inside the cryomodule
    An example of niobium-based 1.3 GHz nine-cell superconducting radio frequency to be put along the beam axis inside the cryomodule

References

[edit]
  1. ^ The International Linear Collider Technical Design Report 2013. International Linear Collider. 2013. Retrieved 14 August 2015.
[edit]


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