The SARAF project present and future

Transcription

1 The SARAF project present and future L. Weissman 11 th IGISOL workshop, Jyvaskyla, June, 2013 Plan of the talk SARAF phase I status applications SARAF phase II plans applications

2 SARAF Soreq Applied Research Accelerator Facility To enlarge the experimental nuclear science infrastructure and promote nuclear research in Israel To develop and produce radioisotopes for bio-medical applications To modernize the source of neutrons at Soreq and extend neutron based research and applications 2

3 Phase I Phase II SARAF vision in 2006 DC 176 MHz 2 ma 2 ma LINAC 2006 Phase I linac (excluding auxiliaries) was expected to be delivered as a turn-key by the industrial company, Research Instruments, former ACCEL. Small local group will participate in the Phase I commissioning and will receive adequate training from the industrial partner Phase II built will be lunched after successful commissioning of Phase I 3

4 SARAF today Phase I LEBT RFQ MEBT PSM Beam line targets D-plate EIS Beam dumps LINAC 2012 Phase The linac I operational, is operated but with not all CW/pulsed specifications protons have and been pulsed reached deutrons beams. Almost For complete CW proton decoupling beam : from 1mA the at ~3.7 former MeV~ industrial 10 hours/trip partners. Commissioning and operation 2 by ma local at ~ 2 team. MeV Local ~ 2 hours/trip team and its expertise has grown considerably The accelerator is used to: Experiments at the temporary beam line Collecting expertise in the accelerator field Study high intensity beam tuning Phase II is under design Development with high intensity targets Basic research in nuclear astrophysics and nuclear medicine 4

5 SARAF Phase I Upstream View PSM MEBT RFQ EIS LEBT A. Nagler, Linac-2006 C. Piel, EPAC-2008 A. Nagler, Linac-2008 I. Mardor, PAC-2009 L. Weissman, Linac-2010 D. Berkovits, Linac-2012 L. Weissman, Rupac

6 PSM Beam dump target Beam lines downstream the linac 6

7 Challenges SARAF phase I Increasing duty cycle (deuterons) Increasing beam energy Increasing beam current Increasing beam availability 7

8 Radio Frequency Quadruple injector 4 rods structure traps and transport the low-energy beam Acceleration and bunching is performed by sophisticated modulation of the rods RFQ works, but. built by NTG/U. Frankfurt 8

9 RFQ conditioning 300 Deuterons CW Forward RF Power (kw) Goal Protons CW Duty Cycle (% ) Stable operation of deuterons only at low DC(<10%) 9

10 Prototype Super conducting Module (PSM) Beam Houses 6 x 176 MHz HWR (Half Wave Resonator) and 3 SC 6T Accelerates protons and deuterons from 1.5 MeV/u to 4 and 5 MeV Very compact design in longitudinal direction Cavity vacuum and insulation vacuum separated 2500 mm M. Pekeler, LINAC

11 HWR Microphonics measurements HWRs are extremely sensitive to LHe pressure fluctuations (60 Hz/mbar) Detuning signal is dominated by the Helium pressure drift Detuning sometimes exceeds +/-200 Hz (~ +/-2 BW) Frequency Detuning 60 Frequency Detuning [Hz] sec 45 sec Time[Sec] * Performed in collaboration with J.Delayen and K. Davis (JLab) 11

12 Deterioration of piezo ranges stepping motor 2011 May 2012 Piezo range (Hz) HWR6 HWR5 HWR4 HWR Cavity BW LV PZT HV PZT Months piezo tuner HWR2 HWR1 12

13 4 kw RF power supplies I. Fishman, LINAC

14 RF couplers Thermal shiled 50 O K Cold window 70 O K Temperature sensor Copper strip to thermal shield for cooling mbar 4 0 K 14

15 Coupler warming up during operation (set for 3.9 MeV) 12 hours HWR6 425 kv HWR4 720 kv HWR3 460 kv HWR2 460 kv HWR5 830 kv RF on HWR1 230 kv RF off RF on RF off Vacuum pressure Warming couplers is the main limiting factor for the acceleration field values. The warming effect differs for different couplers 15

16 Experience with the Tungsten Beam dump The beam dump 50 micron Tungsten sheet fused to a water cooled cooper plate. Up to 10 MeV, no activation and low neutron radiation is expected. H mm 16

17 Tungsten Pin Beam dump A prototype tested up to 1 kw with 3.7 MeV and 2 MeV beams A. Arenstam et al, submitted JINST 17

18 Example of radioisotope production 103 Pd production via 103 Rh(d,2n) 103 Pd reaction deuteron beam filling ports Rh foil metal coolant frame I. Silverman et al., NIM B261, (2007) 18

19 Vacuum protection target fast valve target 1,0E-02 pre-target sec 6 1,0E-03 sec 4 d-plate 1,0E-04 VAT transition current Pressure(mbar) 1,0E-05 1,0E-06 1,0E-07 1,0E-08 1,0E-09 0,3 0,25 0,2 0,15 0,1 0,05 Current (ma) 19 1,0E Arb. time (s) The accelerator vacuum protection worked well during the tests 19

20 Foil target tests 25 µm SS + 1 mm NaK + 2 mm SS base Maximum power ~ 1 kw Maximum irradiation time > 40 hours This dose corresponds to one displacement per target atom 20

21 Lithium jet circulating (LiLiT) Measured velocity 7 m/s Maximum e power density 2.0 MW/cm 4 m/s 18 mm S. Halfon et al. App. Rad. Isot. 2011, INS , CARRI

22 Protons on Li target 7 Li(p,n) 7 Be E thres =1.88 MeV G. Feinberg et al., PRC 2012, M. Freidman et al., NIM 2013 Application of protons at ~ 1.92 MeV produce spectrum similar to a Maxwelian distribution at ~ kt=30 kev This distribution mimics stellar neutron spectrum n/s/ma 22

23 Experience with accelerated deuterons Water flow 5 MeV deuterons n/sec/ma Isotropic Fast neutrons up to 20 MeV 4.7 MeV d beam Fast neutrons 1,0E+04 1,0E+03 Measured raw neutron spectrum 150 µm LiF layer Count 1,0E+02 1,0E+01 T. Hirsh PhD. Thesis 1,0E E(MeV) 23

24 SARAF future plans Continue to collect experience with Phase I and high power targets Continue improve the Phase I performance Demonstrate RFQ CW operation for deuterons Keep existing RFQ or build another RFQ Sign a contract with vendor(s) to design and build the Phase II linac up to 40 MeV Operation by

25 ANL conceptual design (2012) 5mA, 40 MeV p/d The ion source and LEBT are in the original position New (RFQ) MEBT and superconducting linac 176 MHz β=0.09 and β=0.16 Half Wave Resonators Total superconducting linac = m 7 low-β HWR operating at 1 MV and 21 high-β HWR operating at 2 MV Beam dynamics study at [B. Mustapha et al. IPAC 2012, J. Rodnizki et al. LINAC12] Total (static and dynamic) power dissipation ~ 350 P. Ostroumov et al. LINAC12 25

26 R&D linac Target Hall (2019) diffractometer Thermal n source radiography 40 m 26

27 High-energy neutron source 40 MeV, 5 ma deuteron beam on a Lithium target: ~10 15 neutrons /s forward angle density at convertor ~10 14 n/s/cm 2 <E> ~ 15 MeV M. Hagiwara et al. Fus. Sci. Tech., 48 (2005) 27

28 RIB based on SARAF neutron source SARAF neutron source thin Uranium target + gas system radioactive ions to a mass separator Conservative rate estimate 10 microns thick 5x5 cm 2 Uranium foil Neutron density n/s/cm fission/s - equivalent of 20 Ci of 252 Cf 28

29 The Main questions 1. What is the physics program? to enlarge the experimental nuclear science infrastructure and promote nuclear research 2. What is the best gas system? 1. IGISOL 2. LISOL 3. CARIBU like system 29

30 Summary SARAF Phase I is operational and being improved SARAF Phase II is under designed SARAF Phase II could become the base of a modern IGISOL-like facility 30

31 2038 IGISOL workshop in Israel? 31

32 Conservative rate estimate 32

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34 Comparison of neutrons flux density Project IFMIF * SPIRAL II * SARAF Reaction specification d(40mev) +Li d(40mev) + C d(40mev) +Li Projectile range in target (mm) Maximum beam current (ma) 2 x Beam spot on the target (cm 2 ) ~100 ~10 ~1 Beam density on the target (ma/cm 2 ) Neutron production over 4π (n/deuteron) ~0.07 ~0.03 ~0.07 Neutron source intensity (n/s) ~10 17 ~10 15 ~10 15 Maximal neutron flux on the back-plate [n/(sec cm 2 )] (0-60 MeV neutrons) ~10 15 ~10 14 ~ <En> on the back-plate (MeV) ~10 ~12 ~10 34 * D.Ridikas et.al. Neutrons For Science (NFS) at SPIRAL-2 (Part I: material irradiations), Internal Report DSM/DAPNIA/SPhN, CEA Saclay (Dec 2003) 34

35 People involved in accelerator &experiments (including students, consulters and partially affiliated personal ) : D. Berkovits, A. Arenshtam, Y. Ben-Aliz, Y. Buzaglo, O. Dudovich,Y. Eisen, I. Eliyahu, G. Finberg, I. Fishman, I. Gavish, I. Gertz, A. Grin, S. Halfon, D. Har-Even, Y. Haruvi, D. Hirshman, T. Hirsh, T. Horovits, B. Keizer, A. Kreisel, D. Kijel, G. Lempert, Y. Luner, A. Perry, E. Reinfeld, J.Rodnizki, G. Shimel, A. Shor, I. Silverman, E. Zemach, L. Weissman. Accelerator operation, maintenance of the accelerator maintenance the infrastructure, users support, work on Phase II < 20 persons 35

36 Insight into RFQ beam loss RFQ power Vacuum pressure increase current LEBT optimization RFQ measured beam transmission 75-85% for 1 ma 60-65% for 4 ma increase current Rate 2 accordance to simulations by B. Bazak 2008 det4 det5 det3 det2 det

37 Beam dump material study - copper 3 MeV x 1 ma 10 cm 2 proton beam for 8 hours Visual inspection did not exhibit any blistering effects Diffusion coefficient of hydrogen in copper as function of temperature 115 mm Measured residual activity 65 Cu(p,n) 65 Z T 1/2 =243 d 37 L. Weissman et al., Linac10, Tsukuba, (2010) L. Weissman et al., JINST 6 (2011) T

38 Example of operation 4 days of operation ~ 0.25 ma CW 5 days of operation ma CW/pulsed 38

39 Operation at higher current ( 1.7 ma for 1.9 MeV) beam current cavities vacuum LiHe level 39

40 HWR parameters Frequency 176 MHz Geom. β 0.09 L acc =βλ 0.15 m E acc 5.5 MV/m V acc 840 kv >4.7x10 8 Q acc ~1.3x10 6 Q ext Loaded BW Cryo load ~130 Hz < 10 max The main goal of the Prototype cryomodule is demonstration of acceleration of high current (> 1mA) CW proton/deuteron beams to variable energy up to 4(5.5) MeV 40

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