Design of a Fast Chopper System for High Intensity Applications

Transcription

1 2007/05/11 Design of a Fast System for High Intensity Applications Christoph Wiesner IAP Frankfurt

2 Contents Introduction Design and Layout of the Multi-Particle Simulation LEBT Outlook

3 Frankfurt Neutron Source FRANZ 150 kv Terminal Volume Type Ion Source W = 120 kev 4 P = 2.4 x 10 W Δt = ns f = 250kHz W = 0.7 MeV 3 P,max = 7 x 10 W Steerer IH W = MeV 4 P,max = 2.1 x 10 W f = 250 khz Reuncher Dipole Magnet Beam Dump Detector Development high n - flux (dc) 7 Li Target Bunch Compressor Ojective: Production of intensive neutron pulses of kev with a repetition rate of 250 khz. 7 Li Target Sample Shielding H 3Li 4Be 0n , MeV Proton Beam γ 7 Li - Target n

4 Function of the Input: 150 ma dc proton eam, 120 kev Output: ns unches, repetition rate f = 250 khz LEBT- 150 kv Terminal W = 120 kev 4 P = 2.4 x 10 W W = 0.7 MeV 3 P,max = 7 x 10 W W = MeV 4 P,max = 2.1 x 10 W Reuncher Beam Dump Detector Development high n - flux (dc) 7 Li Target Volume Type Ion Source Δt = ns f = 250kHz Steerer IH f = 250 khz Dipole Magnet Bunch Compressor 7 Li Target

5 Possile s Types Disc Chopping in RFQ Electrical Magnetic System

6 Functional Principle of the Dipole System Beam Diagnostics Dipole Magnet f = 250 khz τ= ns Resonant Circuit High Current Proton Storage Ring

7 Functional Principle of the Dipole System Aperture time 1,0 Varying the aperture leads to different unch lengths and intensities. Transmission / % 0,8 0,6 0,4 0, t / ns

8 Layout Dipole System Beam Diagnostics Parameter Setting: Dipole Magnet B max = 0.2 T Dipole Length = 0.3 m f = 250 khz τ= ns Total System Length = 0.6 m Resonant Circuit 0.3m High Current Proton Storage Ring Gap Height = 0.06 m 0.6m B( t) = Bmax sin( ωt + Φn)

9 Layout LEBT Beam Diagnostics Dipole Magnet f = 250 khz τ= ns Resonant Circuit High Current Proton Storage Ring LEBT Solenoid 1: Aperture 150mm Solenoid 2-4: Aperture 100mm 150 kv Terminal W = 120 kev 4 P = 2.4 x 10 W W = 0.7 MeV 3 P,max = 7 x 10 W W = MeV 4 P,max = 2.1 x 10 W Reuncher Beam Dump Detector Development high n - flux (dc) 7 Li Target Volume Type Ion Source Δt = ns f = 250kHz Steerer IH f = 250 khz Dipole Magnet Bunch Compressor 7 Li Target

10 Ion Source x x x Gate Valve 70 Bellows 100 Beam Trafo 40 Bellows 100 Steerer Layout LEBT 408 Diagnostic Tank System Pump Tank H -Beam Dipole Solenoid 1 Solen. 2 Solen. 3 Solen } ±50

11 Schematic View of LEBT Simulation Programs used: Lintra (Sek1, Sek2) DipMag (Dipole)

12 Input Distriution 60 S olenoi d 1 Solenoid 2 Solenoid 3 Solenoid 4 50 Strahlradius r [mm] Start Parameters Ion Source Beam Radius: 6 mm Divergence Angle: 80 mrad Homogeneous Distriution (Assumed) Dipol ausgeschaltet Dipol eingeschaltet

13 Phase Distriution in front of Dipole 60 S olenoi d 1 Solenoid 2 Solenoid 3 Solenoid 4 50 Strahlradius r [mm] Dipol ausgeschaltet Dipol eingeschaltet B (Sol1) = 0.245T B (Sol2) = 0.1T

14 Simulation Dipole System 60 Solenoid 1 Solenoid 2 Solenoid 3 Solenoid 4 50 Strahlradius r [mm] Dipol ausgeschaltet Dipol eingeschaltet 0.6m: Slit 0.3m: End Dipole B max (Dipole)= 0.2 T Slit d=6cm

15 Phase Distriution ehind Slit B max (Dipole)= 0.2 T 60 S olenoi d 1 Solenoid 2 Solenoid 3 Solenoid 4 50 Strahlradius r [mm] Dipol ausgeschaltet Dipol eingeschaltet

16 60 S olenoi d 1 Solenoid 2 Solenoid 3 Solenoid 4 50 Strahlradius r [mm] Dipol ausgeschaltet Dipol eingeschaltet

17 Schematic View of LEBT Beam Envelope

18 Schematic View of LEBT Dip ole off Dipole on

19 creates different eam distriution (depending on direction of Magnetic Field). Spatial Distriution in front of RFQ 60 S olenoi d 1 Solenoid 2 Solenoid 3 Solenoid 4 50 Strahlradius r [mm] Dipol ausgeschaltet Dipol eingeschaltet

20 Phase Distriution in front of RFQ

21 Outlook: To Do Multi-Particle Simulations Beam Dynamics in LEBT Variation of Parameters Beam Dynamics in Space Charge Compensation? Emittance Estimations Technical Implementation Choose Type of Dipole Design Vacuum Chamer Design Electronic Control