IPAC2021 - Classification: MC6: Beam Instrumentation, Controls, Feedback and Operational Aspects / T26 Photon Beam Lines and Components

Paper	Title	Page
MOPAB299	STRUCTURAL OPTIMIZATION DESIGN OF FARADAY CUP FOR BEAM COMMISSIONING OF CSNS	943
	A.X. Wang, L. Kang, M. Meng, J.L. Sun IHEP, Beijing, People’s Republic of China J.X. Chen, H.Y. He, L. Liu, R.H. Liu, X.J. Nie, C.J. Ning, R.Y. Qiu, G.Y. Wang, T. Yang, J.B. Yu, Y.J. Yu, J.S. Zhang, D.H. Zhu IHEP CSNS, Guangdong Province, People’s Republic of China
	Faraday cup is used to absorb and stop the beam during the two phases of beam commissioning, such as the front end (FE) system and the temporary line after the drift tube linac (DTL) at the Chinese Spallation Neutron Source (CSNS). According to the beam physical parameters, graphite is selected to stop the beam directly, and oxygen-free copper which is just behind the graphite as the thermal conductive material. By the analysis and comparison of the target type and cooling efficiency, the single slant target is adopted. The incident angle between the target surface and the beam is set as 10°, meanwhile a new waterfall type water-cooling structure with parallel tunnels is designed to improve the cooling efficiency. The finite element software ANSYS is used for thermal analysis of the model, by which the diameter and interval of water cooling tunnels are optimized. The faraday cup discussed in this paper is finally successfully installed in the beam commissioning line and went well.
	Poster MOPAB299 [1.113 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB299
About •	paper received ※ 13 May 2021 paper accepted ※ 08 July 2021 issue date ※ 19 August 2021
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WEPAB292	Application of Machine Learning to Predict the Response of the Liquid Mercury Target at the Spallation Neutron Source	3340
	L. Lin, S. Gorti, J.C. Mach, H. Tran, D.E. Winder ORNL, Oak Ridge, Tennessee, USA
	Funding: Basic Energy Sciences U.S. Department of Energy SC-22/Germantown Building 1000 Independence Avenue., SW Washington, DC 20585 P: (301) 903 - 3081 F: (301) 903 - 6594 The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is currently the most powerful accelerator-driven neutron source in the world. The intense proton pulses strike on SNS’s mercury target to provide bright neutron beams, which also leads to severe fluid-structure interactions inside the target. Prediction of resultant loading on the target is difficult particularly when helium gas is intentionally injected into mercury to reduce the loading and mitigate the pitting damage on the target’s internal walls. Leveraging the power of machine learning and the measured target strain, we have developed machine learning surrogates for modeling the discrepancy between simulations and experimental strain data. We then employ these surrogates to guide the refinement of the high-fidelity mercury/helium mixture model to predict a better match of target strain response.
	Poster WEPAB292 [0.930 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB292
About •	paper received ※ 19 May 2021 paper accepted ※ 02 July 2021 issue date ※ 10 August 2021
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THPAB269	Compton Spectrometer for FACET-II	4332
	B. Naranjo, G. Andonian, A. Fukasawa, W.J. Lynn, N. Majernik, J.B. Rosenzweig, Y. Sakai, O. Williams, M. Yadav, Y. Zhuang UCLA, Los Angeles, California, USA
	Funding: DARPA GRIT Contract 20204571, DOE HEP Grant DE-SC0009914 We present the design of a Compton spectrometer for use at FACET-II. A sextupole is used for magnetic spectral analysis, giving a broad dynamic range (180 keV through 28 MeV) and the capability to capture an energy-angular double-differential spectrum in a single shot. At low gamma energies, below 1 MeV, Compton spectroscopy becomes increasingly challenging as the scattering cross-section becomes more isotropic. To extend the range of the spectrometer down to around 180 keV, we use a 3D-printed tungsten collimator at the detector plane to preferentially select forward-scattered electrons at the Compton edge.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB269
About •	paper received ※ 20 May 2021 paper accepted ※ 22 July 2021 issue date ※ 19 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB270	Pair Spectrometer for FACET-II	4336
	B. Naranjo, G. Andonian, A. Fukasawa, N. Majernik, M.H. Oruganti, J.B. Rosenzweig, Y. Sakai, O. Williams, M. Yadav UCLA, Los Angeles, California, USA N. Cavanagh, G. Sarri Queen’s University of Belfast, Belfast, Northern Ireland, United Kingdom A. Di Piazza, C.H. Keitel MPI-K, Heidelberg, Germany E. Gerstmayr, S. Meuren, D.A. Reis, D.W. Storey, V. Yakimenko SLAC, Menlo Park, California, USA R. Holtzapple CalPoly, San Luis Obispo, California, USA C. Nielsen AU, Aarhus, Denmark
	Funding: DARPA GRIT Contract 20204571, DOE HEP Grant DE-SC0009914 We present the design of a pair spectrometer for use at FACET-II, where there is a need for spectroscopy of photons having energies up to 10 GeV. Incoming gammas are converted to high-energy positron-electron pairs, which are then subsequently analyzed in a dipole magnet. These charged particles are then recorded in arrays of acrylic Cherenkov counters, which are significantly less sensitive to background x-rays than scintillator counters in this case. To reconstruct energies of single high-energy photons, the spectrometer has a sensitivity to single positron-electron pairs. Even in this single-photon limit, there is always some low-energy continuum present, so spectral deconvolution is not trivial, for which we demonstrate a maximum likelihood reconstruction. Finally, end-to-end simulations of experimental scenarios, together with anticipated backgrounds, are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB270
About •	paper received ※ 20 May 2021 paper accepted ※ 28 July 2021 issue date ※ 18 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB273	Spectral Reconstruction for FACET-II Compton Spectrometer	4346
	Y. Zhuang, B. Naranjo, J.B. Rosenzweig, M. Yadav UCLA, Los Angeles, USA
	Funding: This work was supported by DOE Contract DE-SC0009914, NSF Grant No. PHY-1549132, and DARPA GRIT Contract 20204571. The Compton spectrometer under development at UCLA for FACET-II is a versatile tool to analyze gamma-ray spectra in a single shot, in which the energy and angular position of the incoming photons are recorded by observing the momenta and position of Compton scattered electrons. We present methods to reconstruct the primary spectrum from these data via machine learning and the EM Algorithm. A multi-layer fully connected neural network is used to perform the regression task of reconstructing both the double-differential spectrum and the photon energy spectrum incident with zero angular offset. We present the expected performance of these techniques, concentrating on the achievable energy resolution.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB273
About •	paper received ※ 20 May 2021 paper accepted ※ 28 July 2021 issue date ※ 16 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

STRUCTURAL OPTIMIZATION DESIGN OF FARADAY CUP FOR BEAM COMMISSIONING OF CSNS

943

A.X. Wang, L. Kang, M. Meng, J.L. Sun
IHEP, Beijing, People’s Republic of China
J.X. Chen, H.Y. He, L. Liu, R.H. Liu, X.J. Nie, C.J. Ning, R.Y. Qiu, G.Y. Wang, T. Yang, J.B. Yu, Y.J. Yu, J.S. Zhang, D.H. Zhu
IHEP CSNS, Guangdong Province, People’s Republic of China

Faraday cup is used to absorb and stop the beam during the two phases of beam commissioning, such as the front end (FE) system and the temporary line after the drift tube linac (DTL) at the Chinese Spallation Neutron Source (CSNS). According to the beam physical parameters, graphite is selected to stop the beam directly, and oxygen-free copper which is just behind the graphite as the thermal conductive material. By the analysis and comparison of the target type and cooling efficiency, the single slant target is adopted. The incident angle between the target surface and the beam is set as 10°, meanwhile a new waterfall type water-cooling structure with parallel tunnels is designed to improve the cooling efficiency. The finite element software ANSYS is used for thermal analysis of the model, by which the diameter and interval of water cooling tunnels are optimized. The faraday cup discussed in this paper is finally successfully installed in the beam commissioning line and went well.

Poster MOPAB299 [1.113 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB299

About •

paper received ※ 13 May 2021 paper accepted ※ 08 July 2021 issue date ※ 19 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB292

Application of Machine Learning to Predict the Response of the Liquid Mercury Target at the Spallation Neutron Source

3340

L. Lin, S. Gorti, J.C. Mach, H. Tran, D.E. Winder
ORNL, Oak Ridge, Tennessee, USA

Funding: Basic Energy Sciences U.S. Department of Energy SC-22/Germantown Building 1000 Independence Avenue., SW Washington, DC 20585 P: (301) 903 - 3081 F: (301) 903 - 6594
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is currently the most powerful accelerator-driven neutron source in the world. The intense proton pulses strike on SNS’s mercury target to provide bright neutron beams, which also leads to severe fluid-structure interactions inside the target. Prediction of resultant loading on the target is difficult particularly when helium gas is intentionally injected into mercury to reduce the loading and mitigate the pitting damage on the target’s internal walls. Leveraging the power of machine learning and the measured target strain, we have developed machine learning surrogates for modeling the discrepancy between simulations and experimental strain data. We then employ these surrogates to guide the refinement of the high-fidelity mercury/helium mixture model to predict a better match of target strain response.

Poster WEPAB292 [0.930 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB292

About •

paper received ※ 19 May 2021 paper accepted ※ 02 July 2021 issue date ※ 10 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB269

Compton Spectrometer for FACET-II

4332

B. Naranjo, G. Andonian, A. Fukasawa, W.J. Lynn, N. Majernik, J.B. Rosenzweig, Y. Sakai, O. Williams, M. Yadav, Y. Zhuang
UCLA, Los Angeles, California, USA

Funding: DARPA GRIT Contract 20204571, DOE HEP Grant DE-SC0009914
We present the design of a Compton spectrometer for use at FACET-II. A sextupole is used for magnetic spectral analysis, giving a broad dynamic range (180 keV through 28 MeV) and the capability to capture an energy-angular double-differential spectrum in a single shot. At low gamma energies, below 1 MeV, Compton spectroscopy becomes increasingly challenging as the scattering cross-section becomes more isotropic. To extend the range of the spectrometer down to around 180 keV, we use a 3D-printed tungsten collimator at the detector plane to preferentially select forward-scattered electrons at the Compton edge.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB269

About •

paper received ※ 20 May 2021 paper accepted ※ 22 July 2021 issue date ※ 19 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB270

Pair Spectrometer for FACET-II

4336

B. Naranjo, G. Andonian, A. Fukasawa, N. Majernik, M.H. Oruganti, J.B. Rosenzweig, Y. Sakai, O. Williams, M. Yadav
UCLA, Los Angeles, California, USA
N. Cavanagh, G. Sarri
Queen’s University of Belfast, Belfast, Northern Ireland, United Kingdom
A. Di Piazza, C.H. Keitel
MPI-K, Heidelberg, Germany
E. Gerstmayr, S. Meuren, D.A. Reis, D.W. Storey, V. Yakimenko
SLAC, Menlo Park, California, USA
R. Holtzapple
CalPoly, San Luis Obispo, California, USA
C. Nielsen
AU, Aarhus, Denmark

Funding: DARPA GRIT Contract 20204571, DOE HEP Grant DE-SC0009914
We present the design of a pair spectrometer for use at FACET-II, where there is a need for spectroscopy of photons having energies up to 10 GeV. Incoming gammas are converted to high-energy positron-electron pairs, which are then subsequently analyzed in a dipole magnet. These charged particles are then recorded in arrays of acrylic Cherenkov counters, which are significantly less sensitive to background x-rays than scintillator counters in this case. To reconstruct energies of single high-energy photons, the spectrometer has a sensitivity to single positron-electron pairs. Even in this single-photon limit, there is always some low-energy continuum present, so spectral deconvolution is not trivial, for which we demonstrate a maximum likelihood reconstruction. Finally, end-to-end simulations of experimental scenarios, together with anticipated backgrounds, are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB270

About •

paper received ※ 20 May 2021 paper accepted ※ 28 July 2021 issue date ※ 18 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB273

Spectral Reconstruction for FACET-II Compton Spectrometer

4346

Y. Zhuang, B. Naranjo, J.B. Rosenzweig, M. Yadav
UCLA, Los Angeles, USA

Funding: This work was supported by DOE Contract DE-SC0009914, NSF Grant No. PHY-1549132, and DARPA GRIT Contract 20204571.
The Compton spectrometer under development at UCLA for FACET-II is a versatile tool to analyze gamma-ray spectra in a single shot, in which the energy and angular position of the incoming photons are recorded by observing the momenta and position of Compton scattered electrons. We present methods to reconstruct the primary spectrum from these data via machine learning and the EM Algorithm. A multi-layer fully connected neural network is used to perform the regression task of reconstructing both the double-differential spectrum and the photon energy spectrum incident with zero angular offset. We present the expected performance of these techniques, concentrating on the achievable energy resolution.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB273

About •

paper received ※ 20 May 2021 paper accepted ※ 28 July 2021 issue date ※ 16 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)