IPAC2016 - Classification: 06 Beam Instrumentation, Controls, Feedback and Operational Aspects / T18 Radiation Monitoring and Safety

Paper	Title	Page
WEPOR019	Development of CVD Diamond Detector for Beam Conditioning Monitor at the SuperKEKB Linac	2707
	S. Kazama, T. Kamitani KEK, Ibaraki, Japan P. Bambade, V. Kubytskyi LAL, Orsay, France
	Positron beams in SuperKEKB will be produced from electromagnetic showers originating from the interaction between primary electron beams and a tungsten target. Since the emittance of primary beams is very small, the target is easy to be destroyed if focused beams are irradiated. In the SuperKEKB LINAC, a plate called spoiler is placed in the upstream of the target to enlarge the beam spot size. If the beam control is in a correct way, radioactive rays will be observed near both the spoiler and the target. However, if the beam control is not successful and primary beams are irradiated directly on the target, significant radiations are observed only near the target. If such a behavior is observed, primary beams must be stopped to protect the target. Since the number of electrons in a bunch is quite large(~10nC), the radiation dose is expected to be very high. Therefore, the radiation detector is required to have a high radiation-tolerance over a long period of time. Diamond has a high radiation tolerance due to its strong covalent bond, and we are now developing radiation detectors using diamond crystals. In this talk, current status including beam test measurements will be shown.
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WEPOR020	Beam Loss Estimation by Measurement of Secondarily Produced Photons under High Average-current Operations of Compact ERL in KEK	2711
	H. Matsumura, K. Haga, K. Hozumi, T. Miura, S. Nagaguro, T. Obina, T. Oyama, S. Sakanaka, A. Toyoda KEK, Ibaraki, Japan N. Yoshihara Tokyo Nuclear Service Co. Ltd., Ibaraki, Japan
	To increase the beam current in the Compact Energy Recovery Linac (cERL) at the High Energy Accelerator Research Organization (KEK), the beam loss must be reduced to less than 0.01% during the transportation of 20 MeV electrons in order to suppress the radiation dose outside the accelerator room. Beam loss locations were successfully identified using the gold activation method, and the beam loss rate was estimated by com-paring the measured dose rate with the simulated dose rate on the roof of the cERL room. Beam operation with beam current of 0.90 mA was achieved with a beam loss rate of less than 0.01%.
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WEPOR021	Residual Radiation Monitoring by Beam Loss Monitors at the J-PARC Main Ring	2715
	T. Toyama, K. Satou J-PARC, KEK & JAEA, Ibaraki-ken, Japan H. Kuboki, H. Nakamura, B. Yee-Rendón KEK, Tokai, Ibaraki, Japan M.J. Shirakata JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	At J-PARC (the Japan Proton Accelerator Research Complex), high intensity proton accelerator, controlling and localizing beam losses and residual radiations are key issue, because the residual radiation limits maintenance work in efficiency and working hours, and then limits machine availability. We are accumulating continuous measurement data of residual radiation after beam stop using beam loss monitors in the Main Ring (MR). The wire cylinder gaseous radiation detectors are used in a proportional counting region. The heads are DC-connected and have a gain as large as 30000 with a bias of -2 kV. We switch the DAQ trigger from "Beam Trigger" to "No Beam Trigger", change the ADC sampling rate to 16 ms, and raise the gain by changing the bias voltage from -1.6 kV to -2.0 kV with a few exceptions when the accelerator operation ends. The offsets are measured with zero bias voltage. Identification of radionuclides has been performed with time decay analysis, with assistance of energy spectrum measurements with the Gamma Ray Spectrometer, Kromek GR1-Spectro.
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WEPOR022	Residual Radiation Measurements at J-PARC MR Using the ASTROCAM 7000HS Newly Developed Radioactive Substance Visualization Camera	2719
	N. Ikeda, T. Sugano MHI-MS, Kobe, Japan K. Genba, M. Komeda, Y. Kuroda, D.M. Matsuura MHI, Komaki-si, Japan A. Harayama, T. Takahashi, S. Watanabe ISAS/JAXA, Kanazawa, Japan H. Nakamura, K. Niki, C. Ohmori, M.J. Shirakata KEK, Ibaraki, Japan S. Takeda OIST, Onna-son, Okinawa, Japan
	Mitsubishi Heavy Industries, Ltd. (MHI) released the ASTROCAM 7000HS, a radioactive substance visualization camera. The ASTROCAM 7000HS incorporates the technologies for the gamma-ray detector used for the ASTRO-H satellite, which MHI has been developing under entrustment from and together with scientists at the Institute of Space and Astronautical Science (ISAS) at the Japan Aerospace Exploration Agency (JAXA), and the design was modified for use on land to commercialize the product. MHI and Mitsubishi Heavy Industries Mechatronics Systems, Ltd. (MHI-MS) performed on-site residual radiation measurements at the 50 GeV Main Ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC) under collaboration with the High Energy Accelerator Research Organization (KEK) and the Japan Atomic Energy Agency (JAEA) and succeeded visualization of radiation hot spots of the accelerator components. The outline of the ASTROCAM 7000HS, the measurement principle and the first measurement results at the J-PARC MR are described.
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WEPOR023	Radiation Shielding Considerations for CEPC-SPPC	2722
	Z.J. Ma, Y.D. Ding, N. Li, Q.B. Wang, M.Y. Yan, Q.J. Zhang IHEP, Beijing, People's Republic of China
	A planned project CEPC-SPPC is under-researched by IHEP, CAS, China. Due to its big circumference and high energy, the radiation shielding issues should be treated more serious than ever whether for the machine itself or the worker and the public. In this paper, we briefly introduce the configurations and parameters of the machine, the tools and principle used in the radiation shielding design, and discuss the preliminary result for the shielding of main tunnel and the synchrotron radia-tion. Some radiation protection issues are listed to be resolved next. All the aspects presented should be dis-cussed and verified, any other unmentioned radiation protection problems will be excavated in the future. CEPC: Circular Electron-Positron Collider SPPC: Super Proton-Proton Collider IHEP: Institute of High Energy Physics CAS: Chinese Academy of Sciences
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WEPOR024	HPGe Detector Application on Monitoring Environmental Samples around the Accelerator	2725
	Y.D. Ding, Z.J. Ma, Q.B. Wang, M.Y. Yan, Q.J. Zhang IHEP, Bejing, People's Republic of China
	Massive experimental works are aimed to clarify the structure of detector including CT with X ray machine, determining the thickness of dead layer with collimating radioactive source and ect. Measuring structure and size of the detector by X-ray computed tomography, measur-ing the dead layer thickness of detector's front surface and side surface though collimated point source method, scanning the dead layer distribution of the entire detec-tor. A finite element analysis software name CST is used to simulate electric field distribution of the HPGe detec-tor. Calibrating the efficiency of HPGe detector by means of point source and soil standard matter, A Monte Carlo software called MCNP is used to simulate detector effi-ciency preliminarily according to the structure parame-ters of the factory, optimizing and verifying simulated results on the basis of measured results. At last, the com-parison of the simulated and the experimental data showed very good agreement.
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WEPOR029	Concept of a Fire and Gas Safety System for Accelerators	2729
	M. Dole, S. Grau, D. Raffourt CERN, Geneva, Switzerland
	Today CERN's facilities are equipped with automatic smoke and gas detection systems. Upon smoke or gas leak detection, local safety actions are automatically performed and alarms indicating the location and type of danger are transmitted to the CERN Fire Brigade. The firefighters then size their intervention based on the information received. The increasing complexity, size and quantity of CERN installations drives safety systems to evolve in the direction of simplicity. Intuitive interfaces are required to cope with high turnover of firefighters, and the inherent multinational environment. Global overview of alarms and safety actions statuses are needed by firefighters to decide on the best strategy for intervention. In some emergency situations, it might be necessary to manually trigger remote actions. CERN is studying a new concept, inspired by French standards, where the detection and protection layers are separated and act independently, but provide a common interface. This paper presents an application of this concept for the SPS* accelerator. Detection, fire-compartment and evacuation zones are presented, as well as the architecture of the detection and protection layers. *SPS: Super Proton Synchrotron
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WEPOR030	Gas Filled RF Resonator Hadron Beam Monitor for Intense Neutrino Beam Experiments	2733
	K. Yonehara, A.V. Tollestrup, R.M. Zwaska Fermilab, Batavia, Illinois, USA R.J. Abrams, R.P. Johnson, G.M. Kazakevich Muons, Inc, Illinois, USA H.M. Dinkel University of Missouri, Columbia, Columbia, Missouri, USA B.T. Freemire IIT, Chicago, Illinois, USA
	Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE HEP STTR Grant DE-SC0013795. MW-class beam facilities are being considered all over the world to produce an intense neutrino beam for fundamental particle physics experiments. A radiation-robust beam monitor system is required to diagnose the primary and secondary beam qualities in high-radiation environments. We have proposed a novel gas-filled RF-resonator hadron beam monitor in which charged particles passing through the resonator produce ionized plasma that changes the permittivity of the gas. The sensitivity of the monitor has been evaluated in numerical simulation. A signal manipulation algorithm has been designed. A prototype system will be constructed and tested by using a proton beam at the MuCool Test Area at Fermilab.
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WEPOR031	Field Emission Radiation Characterization of LCLS-II Cavities	2736
	M. Santana-Leitner, C. Adolphsen, L. Ge, Z. Li, T.O. Raubenheimer, M.C. Ross SLAC, Menlo Park, California, USA S. Aderhold, A. Grassellino, O.S. Melnychuk, R.V. Pilipenko, D.A. Sergatskov Fermilab, Batavia, Illinois, USA
	Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515 LCLS-II XFEL facility at the SLAC National Accelerator Laboratory will accelerate CW beams of up to 300 uA to 4 GeV using superconducting radio frequency cavities. Before installation, fully assembled cryomodules will be tested at Fermilab and Jefferson Lab. Besides the basic measurements of cavity gradients and cryogenic heat loads, radiation and dark current levels will be recorded. The latter parameters need to be limited to ensure the safety of the machine and the lifetime of radio-sensitive components installed near the cavities. In this paper we describe the simulation studies being done in preparation of tests, where expected radiation measurements in the different detectors are correlated with field emission and with dark currents in Faraday cups at each end of the cryomodule. This work includes simulations using a detailed model of the cryomodules and detectors, where field emission data generated with Track3P is parsed to the FLUKA radiation transport code.
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WEPOR059	Calculation for the Radiation Dose in Storage Ring Hall based on Monte Carlo Method	2805
	S. Huang, T.L. He, S.C. Zhang, T. Zhang USTC/NSRL, Hefei, Anhui, People's Republic of China
	Radiation dose assessment in synchrotron radiation facility is challenging due to the complexity and uncertainties of radiation source terms induced by high energy particle accelerator. Hefei light source (HLS) is the first dedicated synchrotron radiation light source in China. Radiation dose assessment for users at HLS Beam lines is highly concerned. This study presents the method calculating the radiation dose in storage ring hall under normal operation state, the simplified Monte Carlo calculation model was introduced in detail. We obtained the results of radiation dose distribution in HLS storage ring hall with using MCNP, which are in the same order of magnitude with the experimental results. It indicates that the method can be used to calculate the radiation dose level in storage ring hall, and it has certain guiding significance for the radiation protection.
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WEPOW059	The NSLS-II Top Off Safety System	2985
	R.P. Fliller, D. Bergman, A. Caracappa, L. Doom, G. Ganetis, Y. Hu, Y. Li, W. Louie, D. Padrazo, O. Singh, J. Tagger, G.M. Wang, Z. Xia BNL, Upton, Long Island, New York, USA
	Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. Top Off operation is the desired mode of operation for 3rd generation light sources to ensure beam current stability for user experiments. However, top off operation introduces the hazard of injecting electrons into the front ends with the beamline shutters open. This hazard can be mitigated with the appropriate safety system. This past year, the NSLS-II has transitioned from decay mode to top off operation with the introduction of the Top Off Safety System (TOSS). Top Off was initially demonstrated September 22, 2015 and become standard mode of operating. In this paper we discuss the top off safety system, operation with the system, and future directions.
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WEPOW060	Top Off Algorithm Development and Commissioning at NSLS-II	2988
	R.P. Fliller, A.A. Derbenev, T.V. Shaftan, G.M. Wang BNL, Upton, Long Island, New York, USA
	Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. Recently, NSLS-II introduced top off as the standard mode of beam delivery for the users. During top off, we are required to maintain the beam current within ±0.5% of nominal, and the bunch to bunch variation over the train less than 20% for all operating conditions. In this paper, we discuss the algorithm used for top off, simulations of various operating conditions and performance of the algorithm during operations.
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Paper

Title

Page

Development of CVD Diamond Detector for Beam Conditioning Monitor at the SuperKEKB Linac

2707

S. Kazama, T. Kamitani
KEK, Ibaraki, Japan
P. Bambade, V. Kubytskyi
LAL, Orsay, France

Positron beams in SuperKEKB will be produced from electromagnetic showers originating from the interaction between primary electron beams and a tungsten target. Since the emittance of primary beams is very small, the target is easy to be destroyed if focused beams are irradiated. In the SuperKEKB LINAC, a plate called spoiler is placed in the upstream of the target to enlarge the beam spot size. If the beam control is in a correct way, radioactive rays will be observed near both the spoiler and the target. However, if the beam control is not successful and primary beams are irradiated directly on the target, significant radiations are observed only near the target. If such a behavior is observed, primary beams must be stopped to protect the target. Since the number of electrons in a bunch is quite large(~10nC), the radiation dose is expected to be very high. Therefore, the radiation detector is required to have a high radiation-tolerance over a long period of time. Diamond has a high radiation tolerance due to its strong covalent bond, and we are now developing radiation detectors using diamond crystals. In this talk, current status including beam test measurements will be shown.

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WEPOR020

Beam Loss Estimation by Measurement of Secondarily Produced Photons under High Average-current Operations of Compact ERL in KEK

2711

H. Matsumura, K. Haga, K. Hozumi, T. Miura, S. Nagaguro, T. Obina, T. Oyama, S. Sakanaka, A. Toyoda
KEK, Ibaraki, Japan
N. Yoshihara
Tokyo Nuclear Service Co. Ltd., Ibaraki, Japan

To increase the beam current in the Compact Energy Recovery Linac (cERL) at the High Energy Accelerator Research Organization (KEK), the beam loss must be reduced to less than 0.01% during the transportation of 20 MeV electrons in order to suppress the radiation dose outside the accelerator room. Beam loss locations were successfully identified using the gold activation method, and the beam loss rate was estimated by com-paring the measured dose rate with the simulated dose rate on the roof of the cERL room. Beam operation with beam current of 0.90 mA was achieved with a beam loss rate of less than 0.01%.

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WEPOR021

Residual Radiation Monitoring by Beam Loss Monitors at the J-PARC Main Ring

2715

T. Toyama, K. Satou
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
H. Kuboki, H. Nakamura, B. Yee-Rendón
KEK, Tokai, Ibaraki, Japan
M.J. Shirakata
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

At J-PARC (the Japan Proton Accelerator Research Complex), high intensity proton accelerator, controlling and localizing beam losses and residual radiations are key issue, because the residual radiation limits maintenance work in efficiency and working hours, and then limits machine availability. We are accumulating continuous measurement data of residual radiation after beam stop using beam loss monitors in the Main Ring (MR). The wire cylinder gaseous radiation detectors are used in a proportional counting region. The heads are DC-connected and have a gain as large as 30000 with a bias of -2 kV. We switch the DAQ trigger from "Beam Trigger" to "No Beam Trigger", change the ADC sampling rate to 16 ms, and raise the gain by changing the bias voltage from -1.6 kV to -2.0 kV with a few exceptions when the accelerator operation ends. The offsets are measured with zero bias voltage. Identification of radionuclides has been performed with time decay analysis, with assistance of energy spectrum measurements with the Gamma Ray Spectrometer, Kromek GR1-Spectro.

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WEPOR022

Residual Radiation Measurements at J-PARC MR Using the ASTROCAM 7000HS Newly Developed Radioactive Substance Visualization Camera

2719

N. Ikeda, T. Sugano
MHI-MS, Kobe, Japan
K. Genba, M. Komeda, Y. Kuroda, D.M. Matsuura
MHI, Komaki-si, Japan
A. Harayama, T. Takahashi, S. Watanabe
ISAS/JAXA, Kanazawa, Japan
H. Nakamura, K. Niki, C. Ohmori, M.J. Shirakata
KEK, Ibaraki, Japan
S. Takeda
OIST, Onna-son, Okinawa, Japan

Mitsubishi Heavy Industries, Ltd. (MHI) released the ASTROCAM 7000HS, a radioactive substance visualization camera. The ASTROCAM 7000HS incorporates the technologies for the gamma-ray detector used for the ASTRO-H satellite, which MHI has been developing under entrustment from and together with scientists at the Institute of Space and Astronautical Science (ISAS) at the Japan Aerospace Exploration Agency (JAXA), and the design was modified for use on land to commercialize the product. MHI and Mitsubishi Heavy Industries Mechatronics Systems, Ltd. (MHI-MS) performed on-site residual radiation measurements at the 50 GeV Main Ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC) under collaboration with the High Energy Accelerator Research Organization (KEK) and the Japan Atomic Energy Agency (JAEA) and succeeded visualization of radiation hot spots of the accelerator components. The outline of the ASTROCAM 7000HS, the measurement principle and the first measurement results at the J-PARC MR are described.

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WEPOR023

Radiation Shielding Considerations for CEPC-SPPC

2722

Z.J. Ma, Y.D. Ding, N. Li, Q.B. Wang, M.Y. Yan, Q.J. Zhang
IHEP, Beijing, People's Republic of China

A planned project CEPC-SPPC is under-researched by IHEP, CAS, China. Due to its big circumference and high energy, the radiation shielding issues should be treated more serious than ever whether for the machine itself or the worker and the public. In this paper, we briefly introduce the configurations and parameters of the machine, the tools and principle used in the radiation shielding design, and discuss the preliminary result for the shielding of main tunnel and the synchrotron radia-tion. Some radiation protection issues are listed to be resolved next. All the aspects presented should be dis-cussed and verified, any other unmentioned radiation protection problems will be excavated in the future.
CEPC: Circular Electron-Positron Collider
SPPC: Super Proton-Proton Collider
IHEP: Institute of High Energy Physics
CAS: Chinese Academy of Sciences

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WEPOR024

HPGe Detector Application on Monitoring Environmental Samples around the Accelerator

2725

Y.D. Ding, Z.J. Ma, Q.B. Wang, M.Y. Yan, Q.J. Zhang
IHEP, Bejing, People's Republic of China

Massive experimental works are aimed to clarify the structure of detector including CT with X ray machine, determining the thickness of dead layer with collimating radioactive source and ect. Measuring structure and size of the detector by X-ray computed tomography, measur-ing the dead layer thickness of detector's front surface and side surface though collimated point source method, scanning the dead layer distribution of the entire detec-tor. A finite element analysis software name CST is used to simulate electric field distribution of the HPGe detec-tor. Calibrating the efficiency of HPGe detector by means of point source and soil standard matter, A Monte Carlo software called MCNP is used to simulate detector effi-ciency preliminarily according to the structure parame-ters of the factory, optimizing and verifying simulated results on the basis of measured results. At last, the com-parison of the simulated and the experimental data showed very good agreement.

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WEPOR029

Concept of a Fire and Gas Safety System for Accelerators

2729

M. Dole, S. Grau, D. Raffourt
CERN, Geneva, Switzerland

Today CERN's facilities are equipped with automatic smoke and gas detection systems. Upon smoke or gas leak detection, local safety actions are automatically performed and alarms indicating the location and type of danger are transmitted to the CERN Fire Brigade. The firefighters then size their intervention based on the information received. The increasing complexity, size and quantity of CERN installations drives safety systems to evolve in the direction of simplicity. Intuitive interfaces are required to cope with high turnover of firefighters, and the inherent multinational environment. Global overview of alarms and safety actions statuses are needed by firefighters to decide on the best strategy for intervention. In some emergency situations, it might be necessary to manually trigger remote actions. CERN is studying a new concept, inspired by French standards, where the detection and protection layers are separated and act independently, but provide a common interface. This paper presents an application of this concept for the SPS* accelerator. Detection, fire-compartment and evacuation zones are presented, as well as the architecture of the detection and protection layers.
*SPS: Super Proton Synchrotron

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WEPOR030

Gas Filled RF Resonator Hadron Beam Monitor for Intense Neutrino Beam Experiments

2733

K. Yonehara, A.V. Tollestrup, R.M. Zwaska
Fermilab, Batavia, Illinois, USA
R.J. Abrams, R.P. Johnson, G.M. Kazakevich
Muons, Inc, Illinois, USA
H.M. Dinkel
University of Missouri, Columbia, Columbia, Missouri, USA
B.T. Freemire
IIT, Chicago, Illinois, USA

Funding: Work supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 and DOE HEP STTR Grant DE-SC0013795.
MW-class beam facilities are being considered all over the world to produce an intense neutrino beam for fundamental particle physics experiments. A radiation-robust beam monitor system is required to diagnose the primary and secondary beam qualities in high-radiation environments. We have proposed a novel gas-filled RF-resonator hadron beam monitor in which charged particles passing through the resonator produce ionized plasma that changes the permittivity of the gas. The sensitivity of the monitor has been evaluated in numerical simulation. A signal manipulation algorithm has been designed. A prototype system will be constructed and tested by using a proton beam at the MuCool Test Area at Fermilab.

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WEPOR031

Field Emission Radiation Characterization of LCLS-II Cavities

2736

M. Santana-Leitner, C. Adolphsen, L. Ge, Z. Li, T.O. Raubenheimer, M.C. Ross
SLAC, Menlo Park, California, USA
S. Aderhold, A. Grassellino, O.S. Melnychuk, R.V. Pilipenko, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA

Funding: Work supported by U.S. Department of Energy contract DE-AC02-76SF00515
LCLS-II XFEL facility at the SLAC National Accelerator Laboratory will accelerate CW beams of up to 300 uA to 4 GeV using superconducting radio frequency cavities. Before installation, fully assembled cryomodules will be tested at Fermilab and Jefferson Lab. Besides the basic measurements of cavity gradients and cryogenic heat loads, radiation and dark current levels will be recorded. The latter parameters need to be limited to ensure the safety of the machine and the lifetime of radio-sensitive components installed near the cavities. In this paper we describe the simulation studies being done in preparation of tests, where expected radiation measurements in the different detectors are correlated with field emission and with dark currents in Faraday cups at each end of the cryomodule. This work includes simulations using a detailed model of the cryomodules and detectors, where field emission data generated with Track3P is parsed to the FLUKA radiation transport code.

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WEPOR059

Calculation for the Radiation Dose in Storage Ring Hall based on Monte Carlo Method

2805

S. Huang, T.L. He, S.C. Zhang, T. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Radiation dose assessment in synchrotron radiation facility is challenging due to the complexity and uncertainties of radiation source terms induced by high energy particle accelerator. Hefei light source (HLS) is the first dedicated synchrotron radiation light source in China. Radiation dose assessment for users at HLS Beam lines is highly concerned. This study presents the method calculating the radiation dose in storage ring hall under normal operation state, the simplified Monte Carlo calculation model was introduced in detail. We obtained the results of radiation dose distribution in HLS storage ring hall with using MCNP, which are in the same order of magnitude with the experimental results. It indicates that the method can be used to calculate the radiation dose level in storage ring hall, and it has certain guiding significance for the radiation protection.

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WEPOW059

The NSLS-II Top Off Safety System

2985

R.P. Fliller, D. Bergman, A. Caracappa, L. Doom, G. Ganetis, Y. Hu, Y. Li, W. Louie, D. Padrazo, O. Singh, J. Tagger, G.M. Wang, Z. Xia
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Top Off operation is the desired mode of operation for 3rd generation light sources to ensure beam current stability for user experiments. However, top off operation introduces the hazard of injecting electrons into the front ends with the beamline shutters open. This hazard can be mitigated with the appropriate safety system. This past year, the NSLS-II has transitioned from decay mode to top off operation with the introduction of the Top Off Safety System (TOSS). Top Off was initially demonstrated September 22, 2015 and become standard mode of operating. In this paper we discuss the top off safety system, operation with the system, and future directions.

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WEPOW060

Top Off Algorithm Development and Commissioning at NSLS-II

2988

R.P. Fliller, A.A. Derbenev, T.V. Shaftan, G.M. Wang
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Recently, NSLS-II introduced top off as the standard mode of beam delivery for the users. During top off, we are required to maintain the beam current within ±0.5% of nominal, and the bunch to bunch variation over the train less than 20% for all operating conditions. In this paper, we discuss the algorithm used for top off, simulations of various operating conditions and performance of the algorithm during operations.

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