12th Int. Beam Instrum. Conf.
ISBN: 9 7 8 - 3 - 9 5 4 5 0 - 2 3 6 - 3

IMAGE ACQUISITION SYSTEM FOR THE INJECTION DUMP AT THE
SPALLATION NEUTRON SOURCE*W. Blokland†, N. Evans, A. Oguz, and D. Willis
Oak Ridge National Laboratory, Oak Ridge, TN, USA
Abstract
We describe the Image Acquisition system for the Injection Dump. This system visualizes the different beamlets,
on the vacuum window after the H- beam is stripped of its
electrons by two stripper foils. One beamlet is from H- withits electrons stripped by the first foil and the second beamlet has its final electron stripped by the second foil. We
used the PXI platform to implement the data-acquisition
including timing decoder. We describe the hardware andsoftware for the system. We use a standard non-radhard
GigE camera to acquire the image from the luminescentcoating on the dump vacuum window. To lower the radiation damage to the camera, we shield it with stainless steel
blocks. We present radiation measurements before and after shielding. We also show the radiation damage over timeto estimate the camera’s lifetime.

INTRODUCTION
The Ring Injection Dump (RID) needs diagnostics toproperly steer two waste beam species, leftover from thecharge exchanging injection scheme, to the dump. The Proton Power Upgrade (PPU) upgrades the magnets in the injection region and confirmation is needed of the new trajectories.
The two waste species are referred to as “H0 beam” (partially stripped H− beam) and “H− beam” (the beam thatmisses the primary foil) see Fig. 1. The width of the beam
is up to 20 cm with vertical size slightly smaller. Both species end up as H+ after passing through a secondary stripping foil.

system transfers the light to a camera, see Ref. [1]. The requirements include an absolution position accuracy of
10 mm, both horizontal and vertical, and to survive an 16hour study period to confirm the particles’ trajectories. The
intention was to install the window with the coating rightbefore the measurement but changes in schedule resulted
in installing the coating window but not the optical system.
Hence no results with actual beam will be presented in thispaper. The coating luminescence will have been reduced
due to radiation damage while running beam without thehaving an optical system but experience with the SNS target coatings indicates that enough luminescence remains toperform the required measurements once the optical system has been installed. The optics are described in Ref. [1].

CAMERA SETUP
The system is based on non-radhard GigE cameras because radhard cameras are expensive or do not have theright features. To use non-radhard cameras we tested theradiation doses during full power beam conditions at different locations, see also Ref. [2]. The results are repeatedin Table 1. The odd locations are at ground level and theeven locations at about 1.5 m (above the beam plane). Location ES (Electron Scanner) is in a straight section of thering and is listed as a control reference. Cameras in thoselocations easily survive multiple years of beam runtime(5000 Hrs/year). We used CERN HiRadMat results fromRef. [3] to convert from dose to Time-to-Death and Timeto-Significant-Event (crash). The calculation confirms thatcameras at the ES location can survive for a long time. The
results in the table show that locations further from the injection dump beamline have lower doses. However, locations 1 and 2 simplify the optical system and location 1 allows for the system to be installed on the floor. Unfortunately, this location has the highest dose rates, thus we will
use shielding to reduce the dose.
Table 1: Camera Locations, Doses, and Expected Time to
Death and Significant Event (SE) at 1.4 MW Beam Power

Figure 1: The Ring Injection Dump line along with the calculated projection of beam particles on dump window.
To visualize the waste species on the injection dump
window, it has been coated with a luminescent coating
made of Al2O3:Cr, similar to the SNS target. An optical___________________________________________* SNS is managed by UT-Battelle, LLC, under contract DE-AC0500OR22725 for the U.S. Department of Energy† blokland@ornl.gov

Location
1
2
3
4
56
ES

Total
(Gy/MWHr)
0.29
0.24
0.04
0.05
0.08
0.08
0.0032Time toDeath (Hrs)
285
339
2246
1797
998
998
25674

Time to SE(Hrs)
0.91
1.09
7.20
5.76
3.20
3.20
82.29

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Content from this work may be used under the terms of the CC-BY-4.0 licence (© 2023). Any distribution of this work must maintain attribution to the author(s), title of the work, publisher, and DOI

12th Int. Beam Instrum. Conf.
ISBN: 9 7 8 - 3 - 9 5 4 5 0 - 2 3 6 - 3

IBIC2023, Saskatoon, Canada
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We investigated shielding blocks of tungsten and stainless steel. While tungsten is more effective as a radiation
shield, it was also a factor of three more expensive, so wechose stainless steel, still at a cost of ~$50k. We also
avoided requiring lifting equipment for installation by using smaller blocks that can be moved by hand, including
blocks with handles to allow for easy camera replacement.
The configuration and blocks are shown in Fig. 2. The
shielding was calculated to shield by a factor of around 30,
we measured almost a factor of 40 lower dose, but this was
at ground level, while in the final installation the camera
will be slightly higher. This brings the estimated Time-toDeath to ~11,000 hrs and the Time-to-Significant-Event(SE) to almost 40 hrs. These are very reasonable numbers,
our typical beam runtime is 5000 hrs/year, and will allow
the system to be maintained and used for many years withminimal replacement cost for the non-radhard camera.

Figure 4: The Camera image after 1800 MWHrs of exposure at 1.4 MW at 1 GeV. Left a close-up of the test image
center.

ACQUISITION SYSTEM
The imaging system’s requirements are:
• Survive a 16-hour study to document the newbeamline’s behavior,• provide position resolution of < 4 mm, and• interface with the EPICS controls system.

Figure 2: The shielding blocks to protect the camera.
The shielding was installed without the optics to performtesting of the non-radhard camera in place. The camera wasa FLIR Blackfly 23S6M-C Mono camera with the Sony
IMX249 sensor. The camera was in place for about a year
and survived but had to be rebooted multiple times.
Figure 3 shows the camera being inserted into the shieldingblocks.

The camera test showed that the system can survive formuch longer than needed for the study. The optics havebeen tested in the lab and has a resolution of 0.2 mm. We
estimate the position accuracy to be 2 mm depending on
the actual signal-to-noise in the field which depends on
how the coating has aged. The acquisition platform is PXIwith LabVIEW. The system is shown in Fig. 5.

Figure 5: System Hardware.

Figure 3: The camera inserted into the shielding blocks arrangement.
After 1800 MWhrs of production beam exposure thecamera image was checked, see Fig. 4. It shows that we can
expect to provide details on the beamlets even after fullproduction beam at 1.4 MW after 50 days.

The PXIe-840 computer runs Windows OS and connects
the control network and the camera through separate ethernet interfaces. The power to the camera is controlled by aPXIe-4112 module to be able to reboot the camera after acrash (Significant Event). To decode the accelerator timingsystems, we use a SNS Timing Adaptor board to transmit
the timing signals over the PXIe bus to the FPGA board, aPXIe-7971, for decoding of beam triggers and informationsuch as timestamps. To satisfy the position accuracy requirement, we put fiducial markers on the coating of theinjection dump window, see Fig. 6. A high intensity lamp,
powered through the BK Precision 1687B power supply,
makes the fiducials visible for calibration before there isbeam on the window.

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IBIC2023, Saskatoon, Canada
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d o i : 1 0 . 1 8 4 2 9 / J A C o W - I B I C 2 0 2 3 - W E P 0 3 1Figure 6: Fiducial markers on the vacuum window.

Software
The software program acquires the image from the camera and provides intensity projections both horizontal andvertical as well as the centroid of the image. Different overlays can be added to the image. A circle that is matched tothe edge of the coated area and a crosshair that the user canalign with a blob in the image. The LabVIEW program interface is shown in Fig. 7.

Figure 8: CS-Studio screen.
implementing the operator screens. The CS-Studio screen
for the Injection Imaging System is shown in Fig. 8.

CONCLUSION
An image acquisition system has been created for the injection dump to visualize the waste beam from the stripping foil. A non-radhard camera is used but shielded to provide months of operation based on measurements and reference data. The system integrates with the SNS EPICSbased controls system to provide data to studiers in the control room. Unfortunately, the installation of the optics system was delayed due to problems with the installation of
the coated vacuum window and no field measurements
have yet been taken.

ACKNOWLEDGEMENTS
Figure 7: LabVIEW program.
Additional features in the program are to display two
generated 2D gaussians to mimic the beamlets, and thestripper foil effect to test the program. Background images
can be taken and subtracted from the acquired images.
The LabVIEW program, besides performing the data acquisition and analysis, also functions as an expert screen
while a CS-Studio interface is available for use in the control room. We use a SNS LabVIEW native Channel Access(CA) server to interface with the EPICS based control system. The LabVIEW program uses a library on top of thisCA Server to generate Extensible Display Manager (EDM)
and Control System (CS) Studio files of the published Process Variables (PVs). These files give you a head start withThe authors wish to thank Melissa Harvey for her workon the shielding.
The authors are grateful for support from the Neutron
Sciences Directorate at ORNL in the investigation of thiswork. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the US Departmentof Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paidup, irrevocable, worldwide license to publish or reproduce
the published form of this manuscript, or allow others to doso, for US government purposes. DOE will provide publicaccess to these results of federally sponsored research inaccordance with the DOE Public Access Plan [4].
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423

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12th Int. Beam Instrum. Conf.
ISBN: 9 7 8 - 3 - 9 5 4 5 0 - 2 3 6 - 312th Int. Beam Instrum. Conf.
ISBN: 9 7 8 - 3 - 9 5 4 5 0 - 2 3 6 - 3

IBIC2023, Saskatoon, Canada
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REFERENCES[1] A. Rakhman, D. Willis, D. Aikens, J. Mason, W. Blokland,N. Evans, et al., "Off-axis, Reflective Schmidt Telescope Design for Proton Beam Imaging System*," in OSA Optical Design and Fabrication 2021, Nov. 2021, paper 120781K.
[2] W. Blokland and A. R. Oguz, “Feasibility Study of a NonRad Camera for the SNS* Ring Injection Dump Imaging System”, presented at the IBIC'20, Santos, Brazil, Sep. 2020, paper THPP32, unpublished.

[3] S. Burger, “Scintillation Screens and Optical Technology fortransverse Profile Measurements”, Presentation at ARIESADA Topical Workshop, Krakow, Poland, Apr. 2019.
[4] Department of Energy Public Access Plan, https://www.energy.gov/sites/prod/files/2014/08/f18/DOE_Public_Access%20Plan_FINAL.pdf.

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