Progress on the Beam Energy Monitor for the SPIRAL2 Accelerator.
The first part of the SPIRAL2 project entered last year in the end of the construction phase at GANIL in France. The facility will be composed by an ion source, a deuteron/proton source, a RFQ and a superconducting linear accelerator. The driver is planned to accelerate high intensities, up to 5 mA and 40 MeV for the deuteron beams. A monitoring system was built to measure the beam energy on the BTI line (Bench of Intermediate Test) at the exit of the RFQ. As part of theMEBT commissioning, the beamenergy will be measured on the BTI with an Epics monitoring application. At the exit of the LINAC, another system will have to measure and control the beam energy. The control consists in ensuring that the beam energy stays under a limit by taking account of the measurement uncertainty. The energy is measured by a method of time of flight; the signal is captured by non-intercepting capacitive pick-ups. This paper describes the BTI monitor interface and presents the system evolution following the design review.
MACHINE PROTECTION SYSTEM FOR THE SPIRAL2 FACILITY
The phase 1 of the SPIRAL2 facility, the extension project of the GANIL laboratory, is under construction in Caen, France. The accelerator is based on a linear solution, mainly composed of a normal conducting RFQ and a superconducting linac. One of its specificities is to be designed to accelerate high power deuteron and heavy ion beams from 40 to 200kW, and medium intensity heavy ion beams as well to a few kW. A Machine Protection System has been studied to control and protect the accelerator from thermal damages for a very large range of beam intensities and powers. This paper presents the technical solutions chosen for this system which is based on two technical subsystems: one dedicated to thermal protection which requires a first PLC associated with a fast electronic system and a second dedicated to enlarged protection which is based on a safety products.
Beam Intensity and Energy Control for the SPIRAL2 Facility
The first part of the SPIRAL2 facility, which entered last year in the construction phase at GANIL in France, consists of an ion source, a deuteron and a proton source, a RFQ and a superconducting linear accelerator delivering high intensities, up to 5 mA and 40 MeV for the deuteron beams. Diagnostic developments have been done to control both beam intensity and energy by non-interceptive methods at the linac exit. The beam current is measured by using couples of ACCT-DCCT installed along the lines and the beam energy by using a time of flight device. This paper gives explanations about the technical solutions, the results and resolutions for measuring and controlling the beam. ACCELERATOR CHARACTERISTICS The SPIRAL2 accelerator, an extension of the GANIL laboratory is under construction at CAEN in France [1]. The beams accelerated by the Linac will range in intensity from a few 10 μA to 1mA for ions, up to 5 mA for deuterons, and in energy from 0.75 up to 14.5 MeV/A for ions, 20 MeV/A for deuterons and 33 MeV for protons. BEAM CONTROLS In order to control these beam characteristics, measuring chains and controlling devices are under development by the Electronic Machine Group at GANIL. Controls of the beam intensity, efficiency, energy and beam power, will be necessary for the kick-off authorization issue by the French Nuclear Safety Authority (ASN). These surveillances are part of the Machine Protection System (MPS) [2] and have to bring: A thermal protection, against direct beam damages, requiring a fast response time (few 10 μs) An enlarged protection which controls the operation domain from the safety point of view. Characteristics of the Beam Intensity Intensity range: Few 10μA to 5mA Duty cycle of the slow chopper: From 1/10000 to 1/1 (frequency of 1Hz from 1/10000 to 1/2000 and a frequency of 5Hz from 1/2000 to 1/1) Duty cycle of the fast chopper: From 1/1000 to 1/100 (repetition frequency from 8,88 kHz to 880 kHz) Figure 1: Scheme of the beam intensity and the beam efficiency control. RFQ LINAC HEBT1DCCT/ACCT MEBTACCT/DCCT LEBT-DCCT