Current status of the liquid lithium target development

Current status of the liquid lithium target development Li. T Team presented by S. Halfon 4 th High-Power Targetry Workshop May 3, 2011 1

Outline v Soreq Applied Research Accelerator Facility (SARAF) overview SARAF v Liquid Lithium Target research application and requirements (BNCT, astrophysics) design features lithium circulation and e-gun experiments 2

SARAF Accelerator Thermal neutron radiography Thermal neutron diffraction Nuclear Astrophysics 5 × SC Modules Phase I 2009 40 Me. V Phase II 2015 Radio Pharmaceuticals Accelerator Parameters Parameter p/d PSM Energy 5 – 40 Me. V p: 4 Me. V, d: 5 Me. V 1. 5 Me. V/u Value Ions RFQ Current 0. 04 – 2 m. A Maintenance Hands-On EIS 20 ke. V/u 3 שקף Radioactive beams • Current upgradeable to 4 m. A

SARAF Phase I – Upstream View PSM MEBT RFQ LEBT EIS A. Nagler, Linac-2006 C. Piel, EPAC-2008 A. Nagler, Linac-2008 I. Mardor, PAC-2009 4

SARAF Phase I – downstream v Commissioning of Phase-I is approaching finalization v The current challenges include conditioning the RFQ to enable acceleration of CW deuterons v 1 m. A CW proton beam have been accelerated through the entire Phase-I up energy of 3. 7 Me. V v Low duty cycle 2. 5 m. A deuteron beam have been accelerated to energy of 4. 3 Me. V PSM D-Plate Beam Dump Target beam line

Neutron producing lithium target 7 Li(p, n)7 Be Ethr(p)= 1. 881 Me. V , Q = -1. 644 Me. V. Produces ke. V-energy forward-collimated neutrons near threshold. Ep=2. 32 7 Be*+n 24. 332 0. 429 Ep=1. 9 -2 7 Be+n 23. 84 Q= -1. 64 Me. V 7 Li+p 22. 196 8 Be gs 4. 942 R. taschek, 1948 C. L. Lee, X. -L. Zhou, Nucl. Instr. and Meth. in Phys. Res. B 152 (1999) 1 -11 6

Boron Neutron Capture Therapy n n 10 B Li 10 B n n 10 B 10 B αB 10 10 B n ~ 109 10 B atoms in cell 1. 2. 3. Selectively deliver 10 B to the tumor cells Irradiate the target region with neutrons The short range of the 10 B(n, a)7 Li reaction product, 5 -8 mm in tissue, restrict the dose to the boron loaded area 7

The neutron energy effect on therapy Optimal Energy for deep-seated tumor: 0. 5 e. V – 10 ke. V – Neutron spectrum from lithium target bombarded with 1. 91 Me. V protons Neutron intensity (a. u. ) Accelerator based BNCT with lithium target: 1. Produce most suitable neutrons for therapy 2. Small- in hospital 3. Good public acceptability 4. Relatively cheap Bisceglie et. al. Phys. Med. Biol. 45 (2000) 49– 58. Neutron flux: Optimal ≈109 s-1 cm-2 on beam port ** (for ~1 hour therapy) SARAF lithium target >1010 s-1 m. A-1 8

Astrophysical research: at Ep=1. 91 Me. V a neutron spectrum of maxwellian with k. T= ~ 28 ke. V is producedtypical stellar neutron energy in s-proces 2. 3 × 1010 n/s. m. A Li. T full-geometry simulation (GEANT 4)

Li. T – High flux ke. V neutron source v Both researches require high neutron flux (~109 n/cm 2/s) hence high power Lithium Target v 4 – 10 k. W beam power (p, 2 -4 m. A, 1. 9 -2. 5 Me. V) v Gaussian beam ( =2 mm, D=12 mm) Project IFMIF * SPIRAL II * Li. T d(40 Me. V) +Li d(40 Me. V) + C p(2 Me. V) +Li Projectile range in target (mm) 19. 1 4. 3 0. 2 Maximum beam current (m. A) 2 x 125 5 2 Beam spot on the target (cm 2) ~100 ~1 2. 5 0. 5 >2 (peak) Reaction specification Beam density on the target (m. A/cm 2) v The target should dissipate power densities of more then ~1 MW/cm 3 * D. Ridikas et. al. “Neutrons For Science (NFS) at SPIRAL-2 (Part I: material irradiations), Internal Report DSM/DAPNIA/SPh. N, CEA Saclay (Dec 2003) 10

Liquid lithium loop SARAF Proton Beam Vacuum chamber Proton Beam Lithium containment tank, heat exchanger and Be-7 cold trap EM pump loop Neutron port Accelerator port 11

Target chamber Lithium nozzle view port beam Beam Direction 10 cm 12

Lithium Nozzle liquid lithium beam 18 mm wide 1. 5 mm thick 1 cm 13

Concave jet - Water test Water Film Water direction 18 mm wide 1. 5 mm thick v Meas. flow rate: 48 l/min v extracted velocity: 26 m/s

Lithium tank Design to remove ~12 k. W Cross Section Heat Exchanger Be Trap 15

Oil cycle Inside the lab Outside the lab Oil chamber Flexible tubes Oil pump Heat exchanger

Electro-magnetic pump Permanent Sm. Co Magnets Electrical Motor

DC electro-magnetic flow meter

Lithium vapor trap beam Tantalum foil

Thermal evaluations v Peak temperature elevation at the beam bombarding area Conservative saturation point: 350 C (lithium boiling point at 10 -5 Torr) max. temp. on surface V=20 m/s 5 mm downstream 20

Be-7 production 7 Be: half-life of 53 days, 478 ke. V gamma radiation. v Annual irradiation with 4 m. A, 2 Me. V proton beam, 8 hours a day, will produce the following dose rate, 30 cm from the system. v Solutions: 1. 2. 3. [1] Most of the Be-7 will be accumulating at the cold trap and heat exchanger area[1]. The temperature in the loop and in the cold trap will be set according thermodynamic analysis of 7 Be in molten lithium. The area will be shielded (~ 1. 5 -3 cm of Pb). The irradiation periods were calculated in advance in order to control the radiation levels. M. Ida et. al. , Fusion Engineering and Design 82 (2007) 2490 -2496. 21

Lithium circulation test v Lithium heated up to 200 C. v Pressure: 8× 10 -6 Torr v Velocity: up to 5 m/s v Stable and full lithium film 22

Lithium insertion and circulation movie 23

A, 20 ke. V (20 k. W) electron gun at 1 Li. T Beam dump Magnetic lens

Electron gun off line tests v E-gun simulation: High intensity – 20 ke. V, ~1 A electron gun will simulate thermal deposition of SARAF proton beam. v E-gun power density: 5. 8 MW/cm 3 at 1 A energy deposition of 2 Me. V, 2 m. A protons in lithium ~2 MW/cm 3 energy deposition of 20 ke. V electrons in lithium 20 µm <5. 8 MW/cm 3 25

E-gun experiment v E-beam focusing, using magnetic lens, on diagnostic plate v Measurement of e-beam distribution (up to 10 m. A) v Applying higher beam power on the lithium flow Electrons beam distribution E-Beam hitting diagnostic plate 26

e-gun experiment results v Electron Beam shape measurement v Velocity measurement - ~3 m/s (~30 % of EM pump capability) v Stable lithium flow at irradiation up to 2 k. W (at 3 m/s) v Excessive evaporation when ~2. 2 k. W beam was applied (at 3 m/s) 27

e-gun on lithium 29

Lithium vapors on viewport window

Temperature calculation for 2. 2 k. W electron irradiation Calculated Max temperature= 380˚C Expected saturation temperature: 350˚C Flow 31

Our future plans v E-gun irradiation at higher flow velocity v Transportation and connection to SARAF accelerator beam line v Proton beam heat removal experiments v Be-7 dynamics in the system v Neutron measurements 32

The Li. T Team: M. Paul, A. Arenshtam, D. Berkovits, M. Bisyakoev, I. Eliyahu, G. Feinberg, N. Hazenshprung, D. Kijel, A. Nagler, I. Silverman Thanks to J. Nolen, C. Reed & Y. Momozaki for the help with design and training Thank you 33

Fire-proof dry room for 20 ke. V e -gun experiments As built system 34

Li. Lit @ 4 k. W heating power Beam Depth wise temperature distribution 35

Li. Lit @ 4 k. W heating power Temperature distribution at the center of the jet Flow direction Beam 36

CFD simulations v 3 D flow simulations are done with Open. Foam (open source CFD code) v Currently only strait wall jet flow is simulated v Planed improvements include concave flow and power deposition 37 שקף

Li. T jet chamber liquid lithium v built for 2 Me. V 3. 5 m. A protons v Gaussian beam spot size with =2 mm view port beam 20 m/s jet 18 mm wide 1. 5 mm thick 38 שקף secondary sample chamber beam heat exchanger and 7 Be cold trap

Argon inlet E-gun port Inspection window Explosion roof, held on hinges Stainless steel fire protection enclosure Stainless walls 39

Radiation from 7 Be The Li. T loop dose rate as function of integral irradiation duration and intensity. Based on the assumption that 5% of the Li is left in the loop 40

Radiation shielding Li reservoir dose rate 30 cm behind a lead shield as function of the lead thickness 41

Electro-magnetic pump parameters v Sm 2 Co 17 permanent magnets: 12 units, 40 x 20 mm v v Operating temperature: up to 300 C Electrical Motor: Three Phase, 1. 5 k. W, 2800 rpm Variable Speed Motion Control: Three Phase, 1. 5 k. W Pump Dimensions: L= 700, D=350, H=320 v v Loop sizes: OD 173. 5 mm, width 20 mm, thickness 6 mm Magnetic Field at center: 3. 2 k. G Momentum Test: 115 N. m Calculated pressure: 8 At 42

Titanium adsorption vacuum pump

Oil temperature 44

מהירויות של המשאבה EMP מס' הרצה יחידות EMP 1 -10 SPEED מהירות m/s טמפרטורה / הספק מקסימאלי )זרם k. W - (m. A )%( 4 -1 )05( 1 )%02( 2 53. 2 )07( 4. 1 * 1. 2 k. W/615 o. C 6 )%52( 5. 2 57. 2 )08( 6. 1 * 1. 2 k. W/614 o. C 7 )%03( 3 41. 3 )011( 2. 2 * 1. 2 k. W/571 o. C * הפרשי טמפרטורות ביחס למהירות זרימה הם על פי רישום ידני 54

צפיפות ההספק המקסימאלית בנסויי הינה 2 2. 85 k. W/cm והצפיפות ההספק הנפחית שהופעלה הינה 3 0. 83 MW/cm פרופיל קרן האלקטרונים בזרם של כ- ) 10 m. A כחול( והתאמתם לגאוסיין )אדום( אשר מרכזו ב- . 78 mm בעל רוחב מחצית גובה של 8. 3 mm וסיגמא של 3. 5 mm 64

טמפרטורת הליתיום המינימאלית שנמדדה במיכל במקביל לטמפרטורת אוזני הנחיר במהלך ארבעת ההקרנות האחרונות בתותח האלקטרונים 74

צילום הליתיום מסוחרר בנחיר בעת הקרנה בתותח אלקטרונים ium Electron Beam spot on lith Lithium flow direction 48

Lithium Vapor Pressure & Evaporation Rate 49

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SARAF – Sores Applied Research Accelerator Facility v To enlarge the experimental nuclear science infrastructure and promote the research in Israel v To develop and produce radioisotopes primarily for bio-medical applications v To modernize the source of neutrons at Soreq and extend neutron based research and applications 52