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The Cryogenics group is responsible for the design, construction, installation, operation and maintenance of cryogenic systems for accelerators of the SSRF.

The radio frequency (RF) power and voltage required for storing the electrons are provided by three cryomodules,   each of which contains a 499.654 MHz superconducting cavity. The cavities, made of Niobium, are bath-cooled with saturated liquid helium. The cryogenic plant is constructed to provide the cryogenic environment to these                     superconducting RF modules.

A safety factor of 1.5 is chosen to estimate the heat load from the superconducting RF (SRF) cavities and the heat     loss from the transfer lines.

The cryogenic plant is mainly composed of main compressor ( for cold box running), recovery compressor (used to   pressurize the cryomodule gas boil-off into the gas buffers in case of unexpected shutdown of refrigerator), cold box with the cooling capacity of 650 W/4.5 K, three 100 m3 helium gas storage tanks, a 100 m3 low pressure helium       buffer tank, main LHe dewar with the volume of 2000 L, multi-channel transfer lines with end box, single-channel       transfer lines, four cryogenic valve boxes serving for four corresponding SRF cavities (three are on-line and the other is off-line), and a LN2 supply system including a 40 m3 storage tank and a vacuum insulated transfer line. The             cryogenic plant can operate continuously more than 8000 hours every year.

The Cryogenics group has developed many cryogenic systems for various projects of both domestic and foreign        institutes, such as:

Superconducting undulator at the SSRF

Superconducting wiggler for SSRF phase-II beamline project

Prototype of superconducting Mini undulator

Cryogenic calorimeter for measuring heat load of superconducting undulator

Multichannel LHe transfer lines for Accelerator Driven Sub-critical System (ADS)

Liquid hydrogen transfer lines for the China Spallation Neutron Source(CSNS)


Meanwhile, the Cryogenics group is committed to developing cutting edge technologies and equipments, including      high temperature superconducting undulators, high temperature superconducting current leads, superconducting joint and so on.


The group is currently composed of 8 members.



Jieping Xu


Jian Cui


Junjie Xu


Jingfang Yu


Ming Li


Xiankai Ji


Yi Ding


Yong Fan



Liquid nitrogen tank and high-purity helium gas tanks.


Multiple channel transfer lines.

Liquid helium and gas helium are transferred to superconducting RF cavities at same time.



The 650 W/4.5 K Liquid helium refrigerator. It provides enough liquid helium to three superconducting RF cavities.