HB2014 - List of Authors (Saha, P.K.)

Paper

Title

Page

Beam Instrumentation at the 1 MW Proton Beam of J-PARC RCS

278

K. Yamamoto, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, K. Okabe, P.K. Saha, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Hashimoto, T. Toyama
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Rapid Cycling Synchrotron(RCS) of Japan Proton Accelerator Complex(J-PARC) is providing more than 300 kW of proton beam to Material and Life science Facility(MLF) and Main Ring(MR). Last summer shutdown, a new ion source was installed to increase output power to 1 MW. In order to achieve reliable operation of 1 MW, we need to reduce beam loss as well. Beam quality of such higher output power is also important for users. We present beam monitor systems for these purposes.

Slides WEO2AB03 [3.242 MB]

THO2AB02

The Kicker Impedance and its Effect on the RCS in J-PARC

369

Y. Shobuda, P.K. Saha, M. Yamamoto
JAEA/J-PARC, Tokai-mura, Japan
Y.H. Chin, Y. Irie
KEK, Ibaraki, Japan
T. Toyama
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Measurements demonstrate that the kicker impedance dominates along the RCS. Based on a newly developed theory, the impedance is measured by observing the beam-induced voltages at the ends of power cable of the kicker. Toward one mega-watt goal, it is essential to take advantage of tune manipulations and the space charge damping effect. A reduction scheme of the kicker impedance is proposed to pursue the ultimate goal at the RCS.

Slides THO2AB02 [9.113 MB]

THO3AB02

Dynamic Correction of Extraction Beam Displacement by Field Ringing of Extraction Pulsed Kicker Magnets in the J-PARC 3-GeV RCS

389

H. Harada, H. Hotchi, S.I. Meigo, P.K. Saha, F. Tamura
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The 3-GeV rapid cycling synchrotron (RCS) of J-PARC is designed for a high-intensity output beam power of 1MW. The RCS is extracted two bunches by using eight pulsed kicker and three DC septum magnets with 25Hz repetition. The extracted beam is simultaneously delivered to the material and life science experimental facility (MLF) as well as the 50-GeV main ring synchrotron (MR). The kicker magnets have the ringing of flat-top field and the ringing causes the position displacement. The displacement is big issue because it causes an emittance growth of the extracted beam directly. In the beam tuning, we performed a timing scan of each kicker magnet by using a shorter pulse beam in order to understand the characteristics of ringing field. We then carefully optimized the trigger timings of each kicker for the ringing compensation. We have successfully compensated the extracted beam displacements to (min., max.) = (1.1 mm, +0.6 mm) as compared to (14 mm, +10 mm) with no ringing compensation. The procedure for ringing compensation and experimental results are reported in this paper.

THO3AB03

Pulse-to-pulse Transverse Beam Emittance Controlling for the MLF and MR in the 3-GeV RCS of J-PARC

394

P.K. Saha, H. Harada, H. Hotchi, T. Takayanagi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The 3-GeV RCS (Rapid Cycling Synchrotron) of J-PARC (Japan Proton Accelerator Research Complex) is a MW-class proton beam source for the muon and neutron production targets in the MLF (Material and Life Science Experimental Facility) as well as an injector for 50-GeV MR (Main Ring). Not only the beam intensity but RCS has to provide two different transverse sizes of the extracted beam for the MLF and MR even in simultaneous operation. Namely, a wider one for the MLF, while a narrower one for the MR. We proposed a pulse-to-pulse direct controlling of the transverse injection painting area so as to ensure a desired extracted beam emittance. The injection system design is capable of changing painting area between MLF and MR. The extracted beam profile for the MR is measured to be sufficiently narrower than that for the MLF and is also shown to be consistent with ORBIT beam simulations. It is thus one remarkable progress in recent high intensity multi-user machine to confirm that the beam parameters can be dynamically controlled and delivered as requested by the users even in simultaneous operation. A detail of both design and experimental studies are presented in this paper.

Slides THO3AB03 [2.225 MB]

Paper	Title	Page
WEO2AB03	Beam Instrumentation at the 1 MW Proton Beam of J-PARC RCS	278
	K. Yamamoto, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, K. Okabe, P.K. Saha, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Hashimoto, T. Toyama J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	Rapid Cycling Synchrotron(RCS) of Japan Proton Accelerator Complex(J-PARC) is providing more than 300 kW of proton beam to Material and Life science Facility(MLF) and Main Ring(MR). Last summer shutdown, a new ion source was installed to increase output power to 1 MW. In order to achieve reliable operation of 1 MW, we need to reduce beam loss as well. Beam quality of such higher output power is also important for users. We present beam monitor systems for these purposes.
	Slides WEO2AB03 [3.242 MB]

THO2AB02	The Kicker Impedance and its Effect on the RCS in J-PARC	369
	Y. Shobuda, P.K. Saha, M. Yamamoto JAEA/J-PARC, Tokai-mura, Japan Y.H. Chin, Y. Irie KEK, Ibaraki, Japan T. Toyama J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	Measurements demonstrate that the kicker impedance dominates along the RCS. Based on a newly developed theory, the impedance is measured by observing the beam-induced voltages at the ends of power cable of the kicker. Toward one mega-watt goal, it is essential to take advantage of tune manipulations and the space charge damping effect. A reduction scheme of the kicker impedance is proposed to pursue the ultimate goal at the RCS.
	Slides THO2AB02 [9.113 MB]

THO3AB02	Dynamic Correction of Extraction Beam Displacement by Field Ringing of Extraction Pulsed Kicker Magnets in the J-PARC 3-GeV RCS	389
	H. Harada, H. Hotchi, S.I. Meigo, P.K. Saha, F. Tamura JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The 3-GeV rapid cycling synchrotron (RCS) of J-PARC is designed for a high-intensity output beam power of 1MW. The RCS is extracted two bunches by using eight pulsed kicker and three DC septum magnets with 25Hz repetition. The extracted beam is simultaneously delivered to the material and life science experimental facility (MLF) as well as the 50-GeV main ring synchrotron (MR). The kicker magnets have the ringing of flat-top field and the ringing causes the position displacement. The displacement is big issue because it causes an emittance growth of the extracted beam directly. In the beam tuning, we performed a timing scan of each kicker magnet by using a shorter pulse beam in order to understand the characteristics of ringing field. We then carefully optimized the trigger timings of each kicker for the ringing compensation. We have successfully compensated the extracted beam displacements to (min., max.) = (1.1 mm, +0.6 mm) as compared to (14 mm, +10 mm) with no ringing compensation. The procedure for ringing compensation and experimental results are reported in this paper.

THO3AB03	Pulse-to-pulse Transverse Beam Emittance Controlling for the MLF and MR in the 3-GeV RCS of J-PARC	394
	P.K. Saha, H. Harada, H. Hotchi, T. Takayanagi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The 3-GeV RCS (Rapid Cycling Synchrotron) of J-PARC (Japan Proton Accelerator Research Complex) is a MW-class proton beam source for the muon and neutron production targets in the MLF (Material and Life Science Experimental Facility) as well as an injector for 50-GeV MR (Main Ring). Not only the beam intensity but RCS has to provide two different transverse sizes of the extracted beam for the MLF and MR even in simultaneous operation. Namely, a wider one for the MLF, while a narrower one for the MR. We proposed a pulse-to-pulse direct controlling of the transverse injection painting area so as to ensure a desired extracted beam emittance. The injection system design is capable of changing painting area between MLF and MR. The extracted beam profile for the MR is measured to be sufficiently narrower than that for the MLF and is also shown to be consistent with ORBIT beam simulations. It is thus one remarkable progress in recent high intensity multi-user machine to confirm that the beam parameters can be dynamically controlled and delivered as requested by the users even in simultaneous operation. A detail of both design and experimental studies are presented in this paper.
	Slides THO3AB03 [2.225 MB]