The University of Michigan has funded the expansion of the High Field Science laser laboratories to accommodate the ZEUS facility. The cleanroom (ISO 7) that houses the laser system and laser beam lines has been substantially extended. The building renovation added two new target areas (TA1 and TA2), a new experimental control room, new target preparation facilities and a new laser control room. Below are some photos of the building renovation and the ZEUS facility construction.
Explore through the photo slideshow below.
The old laboratories were completely removed to make space for the extended laser clean room, new ZEUS target areas experimental control room and target facilities.
Cement was poured into the building for the thick radiation shielding walls and floor.
The radiation shielding was extended to the full height of the building to protect the upper level offices.
The new laser cleanroom (not yet clean!).
The target areas have thick, rolling shielding doors that close before laser shots.
The new Target Area 1. The window in the shielding wall will allow a long focal length focusing geometry.
The new corridor running alongside the experimental control room.
The experimental control room – new furniture to come.
The building renovation is completed.
November 18, 2021
Explore through the photo slideshow below.
The installation of the Amplitude Pulsar front end.
Optical tables for the ZEUS amplifiers installed in a clean room.
500 TW experimental chamber in the Target Area 2.
Two ATLAS 100 Nd:glass pump lasers designed to pump the final ZEUS amplifier installed in a clean room.
Clean room with a 500 TW compressor vacuum vessel and a beam line going into the ZEUS Target Area 3.
ZEUS switch yard #2 vacuum vessel in the lab
3PW compressor and switchyard #1 vacuum vessels in the ZEUS facility clean room.
Graduate Student, Joshua Latham, cleaning the 3 PW compressor and switchyard #1 vacuum vessel.
Assembled and vacuum leak tested the ZEUS 3 PW compressor and switchyard #1 .
The switchyard #3 vacuum vessels, which holds a long (~20 meters) focusing optics for laser wakefield experiments in the ZEUS facility clean room.
Cleaning of the switchyard #3 vacuum vessels.
Optical tables enclosure installation is completed.
A 12 inch diameter vacuum deformable mirror, controller and wavefront sensor in the ZEUS clean room.
Prof. Igor Jovanovic has led the design of radiation shielding for the new ZEUS target areas using FLUKA and Geant4 codes.
All radiation-generating facilities have a legal obligation to protect their personnel from ionizing radiation. Each facility has different requirements that must be addressed by the shielding, so specific designs need to be developed and ultimately implemented. For GeV-level accelerators, several meters of radiation shielding or a beam dump combined with radiation shielding are required to reduce the radiation dose to a safe level. We developed a facility design suited for shielding of the gas target area in ZEUS, which includes an electron beam dump. The overall design goal is to limit the hourly dose to 0.02 mSv/h (2 mrem/h) and the annual dose to 1 mSv/year (100 mrem/year), according to the radiation safety regulations. The facility design is illustrated in Fig. 1, which does not display the local shielding (beam dump).
We conducted Monte Carlo simulations using FLUKA and validated them in Geant4. An additional validation was performed with the design of similar facility. The simulation geometry is shown in Fig. 2 and includes the optimization of the composition, thickness, and width of stacked layers of the beam dump. Representative results for the prompt dose are shown in Fig. 3. Also important to the facility design is the longer-term activation, for which the simulation was also carried out (Fig. 4).
Figure 2: (a) Simulation geometry (top view) in the Monte Carlo code FLUKA. (b) Different stacking methods are used to test the effectiveness of the radiation shielding. (c) The same simulation geometry (side view) is also defined in the Geant4 for comparison.
Figure 3: Comparison of the ambient dose equivalent between the (a) three-layer and (b) five-layer stacking configuration with the HD concrete and iron stacking. The difference between the two configurations is shown in (c) and (d).
Figure 4: Example simulation of the activation in ZEUS gas target area.
Solid Target Area Shielding Design
The solid target area is another major experimental area of ZEUS for which the shielding design is necessary. Preliminary designs have been developed to address the challenging environment of higher beam divergence than in the gas target area and the multi-particle environment that requires a combination of shielding materials and geometries. Preliminary FLUKA modeling is illustrated in Fig. 5.
Read more in the publication:
T. Shi, D. Sun, I. Jovanovic, G. Kalinchenko, K. Krushelnick, C. C. Kuranz, A. Maksimchuk, J. Nees, A. G. R. Thomas, and L. Willingale, “Optimization of the Electron Beam Dump for a GeV-class Laser Electron Accelerator,” Applied Radiation and Isotopes 176, 109853 (2021).