[en] The European Spallation Source (ESS) will be part of the future European research infrastructure providing experimental possibilities for research from both academia and industry. A proton accelerator is under development at the ESS. The ESS collects expertise from 17 participating countries. The ESS goal is to complete an accelerator with capability of providing 5 MW proton beam with acceptable environment and to commission the beam up to the target by 2019. The pre-construction phase aims at identifying the requested cryogens to operate the accelerator using superconducting materials, the rotating tungsten target and necessary cryogenic systems. Liquid helium, liquid nitrogen and liquid hydrogen are considered for those purposes. This paper describes the conceptual cryogenic design of the system involved in the construction. (author)

[en] The LHC Interaction Region Quadrupoles (IRQ) will be shipped from Fermilab to CERN. The IRQ magnets are supported by glass fiber supports. A prototype cryostat support has been tested under various mechanical forces in order to check its mechanical behavior. These measurements have been made in order to validate a numerical model. A large range of mechanical loads simulates loads due to the shipment of the device, the weight of the cold mass as well as the cool down conditions. Its mechanical properties are measured by means of a dedicated arrangement operating at room temperature. This study appears to be essential to optimize the design of the support. The purpose of this note is to summarize the first measurements related to mechanical tests performed with the support

[en] In support of the Charged Kaons at the Main Injector (CKM) experiment [1], an SRF cryomodule was designed, assembled, and tested at Fermilab. The cryomodule prototype consists of a single niobium 13-cell 3.9 GHz superconducting RF cavity installed in its horizontal cryostat. The prototype was simplified to hold an additional dummy cavity in place of a second 13-cell SRF cavity. Although this cryomodule was originally intended for beamline deflection in the CKM experiment, this first preliminary test aims to compliment existing vertical 3-cell 3.9 GHz SRF cavity testing and also to gain expertise in the field of SRF testing. The cryomodule's thermal and mechanical design is reported. The test process and instrumentation is described. The first operational cooldown with RF powering is discussed and some cryogenic results are given

[en] The low-β magnet systems are located in the LHC insertion regions around the four interaction points. They are the key elements in the beams focusing/defocusing process and will allow proton collisions at a luminosity of up to 10³⁴cm^-2s^-1. Large radiation dose deposited at the proximity of the beam collisions dictate stringent requirements for the design and operation of the systems. The hardware commissioning phase of the LHC was completed in the winter of 2010 and permitted to validate this system safe operation. This paper presents the analysis used to qualify and quantify the safe operation of the low-β magnet systems in the Large Hadron Collider (LHC) for the first years of operation.

[en] Construction of a new facility known as the MuCool Test Area (MTA) has been completed at Fermi National Accelerator Laboratory. This facility supports research in new accelerator technologies for future endeavors such as a Neutrino Factory or Muon Collider. During the summer of 2004, an initial set of tests was completed for the filling of a convection-style liquid hydrogen absorber designed by KEK. The absorber contained 6.2 liquid liters of hydrogen and was tested for a range of heating conditions to quantify the absorber's heat exchanger performance. Future work at Fermilab includes the design, construction, and installation of a forced-flow absorber to be used with other components built to investigate the properties of a muon ionization cooling channel. A Tevatron-style refrigerator/compressor building is to be operational by spring of 2006 in support of the absorber tests and also to provide 5-K helium and liquid nitrogen to a 5-T solenoid magnet, an active element of the future test apparatus. The refrigerator will be configured in such a manner as to meet the 5 K and 14-20-K helium needs of the MTA. This paper reviews the challenges and successes of the past KEK absorber tests as well as looks into the future cryogenic capabilities and intentions of the site

[en] The Horizontal Test Stand (HTS) SRF Cavity and Cryomodule 1 (CM1) of eight 9-cell, 1.3GHz SRF cavities are operating at Fermilab. For the cryogenic control system, how to hold liquid level constant in the cryostat by regulation of its Joule-Thompson JT-valve is very important after cryostat cool down to 2.0 K. The 72-cell cryostat liquid level response generally takes a long time delay after regulating its JT-valve; therefore, typical PID control loop should result in some cryostat parameter oscillations. This paper presents a type of PID parameter self-optimal and Time-Delay control method used to reduce cryogenic system parameters oscillation.

[en] Fermilab is heavily engaged and making strong technical contributions to the superconducting radio-frequency research and development program (SRF R and D). Four major SRF test areas are being constructed to enable vertical and horizontal cavity testing, as well as cryomodule testing. The existing Fermilab cryogenic infrastructure has been modified to service Fermilab SRF R and D needs. The first stage of the project has been successfully completed, which allows for distribution of cryogens for a single cavity cryomodule using the existing Cryogenic Test Facility (CTF) that houses three Tevatron satellite refrigerators. The cooling capacity available for cryomodule testing at MDB results from the liquefaction capacity of the CTF cryogenic system. The cryogenic system for a single 9-cell cryomodule is currently operational. The paper describes the status, challenges and operational experience of the initial phase of the project

[en] As part of Fermilab's study of a Very Large Hadron Collider (VLHC), a water-cooled photon stop was proposed as a device to intercept the synchrotron radiation emitted by the high-energy proton beams in the high-field superconducting magnets with minimal plug-cooling power. Photon stops are radiation absorbers operating at room temperature that protrude into the beam tube at the end of each bending magnet to scrape the synchrotron light emitted by the beam one magnet up-stream. Among the technological challenges regarding photon stops is their cryo-design. The photon stop is water-cooled and operates in a cryogenic environment. A careful cryo-design is therefore essential to enable operation at minimum heat transfer between the room temperature sections and the cryogenic parts. A photon stop cryo-design was developed and a prototype was built. This paper presents the results of the cryogenic experiments conducted on the first VLHC photon-stop prototype

[en] The low-β magnet systems are located in the Large Hadron Collider (LHC) insertion regions around the four interaction points. They are the key elements in the beams focusing/defocusing process allowing proton collisions at luminosity up to 10³⁴cm^-2s^-1. Those systems are a contribution of the US-LHC Accelerator project. The systems are mainly composed of the quadrupole magnets (triplets), the separation dipoles and their respective electrical feed-boxes (DFBX). The low-β magnet systems operate in an environment of extreme radiation, high gradient magnetic field and high heat load to the cryogenic system due to the beam dynamic effect. Due to the severe environment, the robustness of the diagnostics is primordial for the operation of the triplets. The hardware commissioning phase of the LHC was completed in February 2010. In the sake of a safer and more user-friendly operation, several consolidations and instrumentation modifications were implemented during this commissioning phase. This paper presents the instrumentation used to optimize the engineering process and operation of the final focusing/defocusing quadrupole magnets for the first years of operation.

[en] In the recently commissioned superconducting RF cavity test facility at Fermilab (SCTF), a 325 MHz, β = 0.22 superconducting single-spoke resonator (SSR1) has been tested for the first time with its input power coupler. Previously, this cavity had been tested CW with a low power, high Q_ext test coupler; first as a bare cavity in the Fermilab Vertical Test Stand and then fully dressed in the SCTF. For the tests described here, the design input coupler with Q_ext ∼ 10⁶ was used. Pulsed power was provided by a Toshiba E3740A 2.5 MW klystron.