Conveners
Target: Target Lifetime
- Bernie Riemer (SNS / ORNL)
Target: Moderators and Reflectors
- Michael Mocko (Los Alamos National Laboratory)
Target: Target Engineering #1
- Yannick Bessler
Target: Target Engineering #2
- Daniel Lyngh
Target: Target Engineering #3
- Yoann Charles (Paul Scherrer Institut)
Target: Neutronics #2
- Fernando Sordo (Consorcio ESS-Bilbao)
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory has a Proton Power Upgrade (PPU) program underway to update the proton beam energy from 1.0 to 1.3 GeV and the power on target from 1.4MW to 2MW at the First Target Station (FTS). A critical requirement of this program is the design and operation of a 2MW target with a life of 1250 hours (4 targets per year), however, less...
The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory produces intense pulses of neutrons for scientific experiments. The neutrons are produced 60 times a second as 0.7 microsecond long pulses of protons traveling at 1.0 GeV and carrying an energy of 23.3 kJ strike target. The elemental mercury target material produces neutrons through spallation reactions. The mercury...
The continuous wave spallation source SINQ has been in operation for 22 years. The proton beam power on target was gradually increased over the past decades and has now reached about 1.0MW. With one exception (the liquid metal target MEGAPIE) cannelloni-type solid state targets were used. These D2O cooled lead/Zr-based targets proved to be very reliable and underwent several design...
Beam interception devices and neutron moderating systems in the ESS target environment are exposed to intense radiations of primary and secondary particles. Radiation induced degradation of the affected functional and structural materials poses challenges to availability and reliability of the neutron production systems. Due to unprecedentedly high proton beam energy driving the spallation...
The ESS Target Station is designed to convert the 2 GeV protons to a high flux of low energy neutrons for scientific research, at 5 MW beam power. It will start receiving proton beam from the linac for neutron production in 2022. Upon commissioning โbeam-on-target,โ the linac will deliver protons at 571 MeV, which is lower than the nominal value 2 GeV. For the first 5 years after the beam...
Beryllium reflectors are used at spallation neutron sources in order to enhance the low-energy flux of neutrons emanating from the surface of a cold and thermal moderator. The design of such a moderator/reflector system is typically carried out using detailed Monte-Carlo simulations, where the beryllium reflector is assumed to behave as an ideal poly-crystalline material. In reality, however,...
The unique properties of solid methane enable the conversion of hot, energetic neutrons into cold neutrons, with an efficiency approximately 3.5 times that of liquid hydrogen based moderators. However, practical applications of solid methane in neutron moderators turned out to be much more challenging than initially expected. Exposure of solid methane at low temperatures to neutron radiation...
The European Spallation Source will be the most powerful neutron source in the world for condensed matter studies. The design of ESS moderator system to deliver thermal and cold neutrons to the instruments was based on the novel concept of low-dimensional moderators which led, after an intense design effort, to a single high-brightness moderator system placed on top of the spallation target....
Studies by the ESS neutronic team have shown that low-dimensional moderators can improve the neutron brightness by more than a factor of two, compared to the common volume moderators. ESS will therefore be equipped with such a moderator. The intended time-averaged proton beam power is 5 WM. Due to ramp up of the accelerator the first generation will operate under partial load of less than 2 MW...
The spectrum moderators deliver to neutron scattering beamlines has to stay as consistent as possible throughout the runcycle of a facility. This means that for hydrogen moderators the ratio of parahydrogen to orthohydrogen especially needs to stay the constant. Especially low dimensional parahydrogen moderators are very sensitive to the ortho- to parahydrogen equilibrium and quickly lose...
The ISIS Facility at RAL has been producing neutrons for science from the original Target Station (TS1 โ 40/50Hz) since 1984. The second, lower power, low-repetition-rate Target Station (TS2 โ 10Hz) came on line in 2008.
The TS1 Project currently in preparation will include the complete replacement of the internal parts of the original Target Station, including redesign of the Target,...
The European Spallation Source is an ambitious project to build a 5 MW spallation neutron source. The Spanish contribution to this European project will be 3% of the total cost. Based on the new tendencies on Science construction projects a significant fraction of this contribution (up to 80 %) will be In kind. ESS-BILBAO Consortium has been committed to channel this contribution.
...
Upgrades to the Spallation Neutron Source will double the power capability of the accelerator complex to enable operation of the new Second Target Station and increase power to the existing First Target Station (FTS). The Proton Power Upgrade (PPU) project achieves this with a 30% increase in proton energy along with higher current. Presently the FTS operates at 1.4 MW of 60 Hz pulses of 1.0...
SNS 2 MW Target Design
Kevin C. Johns
Oak Ridge National Laboratory, Oak Ridge TN
The Spallation Neutron Source (SNS) in Oak Ridge, TN is currently in the preliminary design phase of the Proton Power Upgrade (PPU) which will further advance neutron research at SNS. The upgrade will increase beam power from the current 1.4 MW to 2.0 MW and the beam energy from 1.0 GeV to 1.3 GeV. Reliable...
Tantalum-clad tungsten targets are a popular choice for spallation neutron production, due to the combination of high neutron yield and corrosion resistance. Such targets typically use the Hot Isostatic Press (HIP) method to bond the cladding to the core; this produces a strong bond but also introduces large residual stresses in the target and cladding. This is a particular concern because...
The European Spallation Source is an ambitious European project with a budget of more than 1800 Mโฌ to build a 5 MW spallation source in Lund (Sweden). For this purpose, it will use a proton beam with a total power of 5 MW which will impact on a tungsten Target cooled by helium gas.
The spallation reactions produced in the ESS target will generate a large number of radioactive isotopes. The...
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory uses a mercury target to generate neutrons. When a proton beam hits the mercury target, the deposited energy causes a very rapid rise in temperature that cause the mercury to cavitate and erode the vessel walls. To mitigate the cavitation erosion, small bubbles of Helium are injected into the mercury target using 50-60 small...
The Second Target Station (STS) is a proposed major upgrade to the Spallation Neutron Source that will provide new cutting-edge neutron scattering capabilities enabling researchers to use the unique properties of neutrons to advance scientific discovery and to solve the most challenging technology problems.
STS Target Systems encompasses the technical components and support facilities...
The proposed Second Target Station (STS) addition to the Spallation Neutron Source will provide world leading neutron scattering capabilities based on cold neutron beams optimized for high brightness.
The Moderator Reflector Assembly (MRA) surrounds the neutron production zone of the STS solid rotating tungsten target and is comprised of 2 coupled hydrogen moderators, one cylindrical and one...
We will review key features of the physics design of the next-generation spallation neutron Target-Moderator-Reflector-Shield (TMRS) assembly Mark-IV for the Manuel Lujan Jr. Neutron Scattering Center at the Los Alamos Neutron Science Center (LANSCE). The new TMRS was designed to improve the neutronic performance in the keV to MeV energy region to advance a variety of nuclear physics...
The neutron Time-Of-Flight (n_TOF) facility at the European Laboratory for Particle Physics (CERN) is a pulsed white-spectrum neutron-spallation source coupled to two flight paths, each one leading to an experimental area: EAR1, 200 m from the target, and EAR2, 20 m above the target. The spallation source is based on a lead target, impacted by a high-intensity 20 GeV/c proton beam. The...
The objective of producing a high brightness neutron source required designing for a very high peak energy deposition per pulse in the tungsten with energy deposition times on the order of 800 nano-seconds. This produces high dynamic stresses in the tungsten. Average heat removal requirements for the 700 kW beam are reduced by using a rotating target and can be met with water cooling with a...
The SPS Beam Dump Facility (BDF) Project [1], currently in its comprehensive design phase, is a proposed general-purpose fixed target facility at CERN, dedicated to the High Energy Physics (HEP) community and specifically to the Search for Hidden Particles (SHiP) experiment in its initial phase in the framework of the Physics Beyond Colliders (PBC) initiative [3].
At the core of the...
The European Spallation Source is an ambitious project to build a 5 MW spallation neutron source. The Spanish contribution to this European project will be 5% of the total cost. Based on the new tendencies on Science construction projects a significant fraction of this contribution (up to 80 %) will be in-kind. ESS-BILBAO Consortium has been committed to channel this contribution. One of the...
The next-generation Lujan Target-Moderator-Reflector-Shield assembly (Mark-4 design) is currently being fabricated and is scheduled for installation during the upcoming extended outage period in Spring of 2020. The new design will offer significantly changed neutronic performance for the four upper-tier flight paths (FPs). The neutronic performance for the remaining lower-tier flight paths...
At SNS the moderators and reflectors are integrated into one component called inner reflector plug (IRP), which essentially delivers desired neutron pulses to all the instruments. The current IRP is operated at a beam power up to 1.4 MW and has an estimated lifetime of ~28 GWhr. The design for the next generation IRP (IRP3) has already been completed. While the main purpose of the design is...
The Spallation Neutron Source (SNS) has been in operation since 2006 at the Oak Ridge National Laboratory. SNS was designed to accommodate two upgrades: the accelerator proton power upgrade (PPU), and a second target station (STS). The PPU project is currently funded and underway, while the STS project is preparing for the US Department of Energy Critical Decision 1 review. The PPU will...
VENUS is an imaging instrument that will have a broad range of neutron wavelengths, from epithermal to cold, and enhanced contrast mechanisms, and will offer novel energy-selective imaging techniques that directly connect the structures, properties, and function of complex engineering materials and systems to reveal practical and fundamental answers about their real-world performance. The...
The China Spallation Neutron Source (CSNS) is an accelerator based multidiscipline user facility located in Dongguan, China. CSNS ramped the beam power to 50kW and consistently achieved an availability of more than 90%. This report emphasizes the status of CSNS Target Station during the operating period. The CSNS target is made of eleven tungsten plates with the different thickness. The...
The China Spallation Neutron Source (CSNS) is an accelerator based multidiscipline user facility constructed in Dongguan, Guangdong, China. The CSNS consists of a linear accelerator, a rapid cycling proton synchrotron accelerating the beam to 1.6 GeV energy, a solid tungsten target station, and three instruments in phase one for neutron scattering applications.
The neutron wavelength spectra...
