Mitglied der HelmholtzGemeinschaft Production and Storage of Polarized

PIT@ANKE p, p, d, d with momenta up to 3. 7 Ge. V/c •

PIT @ ANKE/COSY Main parts of a PIT: • Atomic Beam Source • Target

Polarized H 2 Molecules Measurements from NIKHEF, IUCF, HERMES show that recombined molecules retain

Polarized H 2 Molecules Eley-Rideal Mechanism Pm = 0. 5 Pa Is there a

Pol. Molecules: The experimental setup ISTC Project # 1861 PNPI, FZJ, Uni. Cologne DFG

The experimental Setup The Lamb-shift Polarimeter m. I = +1/2 N+1/2 – N-1/2 P=

The experimental setup The Lamb-shift Polarimeter H 2+ H 2 S (α 1) H+

Polarized H 2 Molecules Polarization losses of the molecules due to: - spin-spin (I↔I)

Experimental results Measurements on Fomblin Oil (Perfluoropolyether PFPE) HFS 3 TCell = 100 K

Recombination on Fomblin (? ) . Bext . . F F F C -O

HD Molecules (Surface: Gold / T = 80 K / B = 0. 528

Signal of the Photomultiplier [a. u. ] HD Molecules Surface: Fomblin on Fused Quarz

HD Molecules H H Brot D Naive Approximation: 2/3 H 1/3 Brot D Bc

Experimental Results for Mass 3 Pz = - 0. 23 Preliminary 18

Production of polarized D 2 and HD ice possible? Polarization Measurement: NMR – Sensor

Conclusion We can measure: - the polarization of atoms and molecules in a storage

Conclusion We can produce polarized H 2, D 2 and HD molecules with large

Slides: 21

Download presentation

Mitglied der Helmholtz-Gemeinschaft Production and Storage of Polarized H 2, D 2 and HD Molecules 10. 09. 2018 by Ralf Engels JCHP / Institut für Kernphysik, FZ Jülich

PIT@ANKE p, p, d, d with momenta up to 3. 7 Ge. V/c • internal experiments – with the circulating beam • external experiments – with the extracted beam 2

PIT @ ANKE/COSY Main parts of a PIT: • Atomic Beam Source • Target gas hydrogen or deuterium • H beam intensity (2 hyperfine states) 8. 2. 1016 atoms / s • Beam size at the interaction point σ = 2. 85 ± 0. 42 mm • Polarization for hydrogen atoms PZ = 0. 89 ± 0. 01 (HFS 1) PZ = -0. 96 ± 0. 01 (HFS 3) • Lamb-Shift Polarimeter • Storage Cell M. Mikirtychyants et al. ; NIM A 721 (0) 83 (2013) 3

Polarized H 2 Molecules Measurements from NIKHEF, IUCF, HERMES show that recombined molecules retain fraction of initial nuclear polarization of atoms! Pm β= Pa Pm = ½ P a The HERMES Collaboration; Eur. Phys. J. D 29, 21– 26 (2004) DOI: 10. 1140/epjd/e 2004 -00023 -5 4

Polarized H 2 Molecules Eley-Rideal Mechanism Pm = 0. 5 Pa Is there a way to increase Pm P (surface material, T, B etc)? 5

Pol. Molecules: The experimental setup ISTC Project # 1861 PNPI, FZJ, Uni. Cologne DFG Project: 436 RUS 113/977/0 -1 H 2+ , D 2+ HD+, H 3+ p, d 6

The experimental Setup The Lamb-shift Polarimeter m. I = +1/2 N+1/2 – N-1/2 P= N+1/2 + N-1/2 m. I = -1/2 R. Engels et al. , Rev. Sci. Instr. 74 4607 (2003) R. Engels et al. , Rev. Sci. Instr. 85 103505 (2014) 7

The experimental setup The Lamb-shift Polarimeter H 2+ H 2 S (α 1) H+ H+ H 2 S (α 1) Efficiency ∙ 2 ∙ 0. 025 = 5 ∙ 10 -12 = 2 ∙ 10 -11 See talk by L. Huxold at 10 th of September (6 pm, Room A 9) 8

Polarized H 2 Molecules Polarization losses of the molecules due to: - spin-spin (I↔I) interactions of the nucleons - Interaction of the nuclear spins I with the rotational magnetic moment J - Interaction with the external magnetic field B n ≈ 1000 - … Naive Model: Bc 2 B 1 - n( ) =P ·e Pm(B, n) = P(B, n) m 0 1+(Bm/B)2 ∙ n/ln 2 Nuclear Polarization of Hydrogen Molecules from Recombination of Polarized Atomsc T. Wise et al. , Phys. Rev. Lett. 87, 042701 (2001). with: Bc = 5. 4 m. T, n ≡ average amount of wall colissions 9

Theory 10

Experimental results Measurements on Fomblin Oil (Perfluoropolyether PFPE) HFS 3 TCell = 100 K Pm = -0. 87 Pm = - 0. 81 ± 0. 02 n = 174 ± 19 c = 0. 993 ± 0. 005 + H 2 p Pm = - 0. 84 ± 0. 02 n = 277 ± 31 R. Engels et al. , Phys. Rev. Lett. 115 113007 (2015) 11

Recombination on Fomblin (? ) . Bext . . F F F C -O -C - O -C O --C F Fused Quarz 12

HD Molecules (Surface: Gold / T = 80 K / B = 0. 528 T / E = 2 ke. V) Pz (D) = -0. 3 Pzz (D) = 0. 12 Pz (H) = -0. 21 H D H 13

HD Molecules (Surface: Gold / T = 80 K / B = 0. 528 T / E = 2 ke. V) H D H 14

Signal of the Photomultiplier [a. u. ] HD Molecules Surface: Fomblin on Fused Quarz T = 80 K / B = 0. 528 T / E = 0. 3 ke. V Pz (H) = - 0. 77 Pz (D) = - 0. 79 Pzz (D) = + 0. 69 15

HD Molecules 16

HD Molecules H H Brot D Naive Approximation: 2/3 H 1/3 Brot D Bc (H 2) Bc (HD) = 2. 4 Distance Brot <-> H increased by 1/3 Distance Brot <-> D decreased by 1/3 Bc ~ Brot / r 3 = 3. 4 17

Experimental Results for Mass 3 Pz = - 0. 23 Preliminary 18

Production of polarized D 2 and HD ice possible? Polarization Measurement: NMR – Sensor T= 3 -10 K Cold Head D 2 ice 19

Conclusion We can measure: - the polarization of atoms and molecules in a storage cell. - the recombination of hydrogen/deuterium atoms on different surfaces and for different HFS. - If Bc is known: the number of wall collisions of the molecules in the cell. - Pay attention: Other depolarizing effects, e. g. magnetic impurities on the surface or charged islands on isolating surfaces, will increase the Bc. 20

Conclusion We can produce polarized H 2, D 2 and HD molecules with large vector- and tensor-polarization (~ 0. 8) in many spin combinations. For what it is usefull? 1. ) More dense polarized targets. 2. ) Spectroscopy of the molecules or molecular ions (Contact with the University of Düsseldorf). 3. ) New insights in chemical reactions / surface physics. 4. ) Polarized fuel to increase the energy output of Fusion reactors. -> see talk on Wednesday, 2: 30 pm 5. ) Polarized targets for laser acceleration. -> see talk by M. Büscher on Wednesday, 5: 05 pm 6. ) EDM measurements ? 7. ) An option to produce polarized molecules for medical application ? 21