1. Different source designs for particle ionization in a pulsed glow discharge Farzad Fani Pakdel November 16, 2006

2. Objective: Ionization of particles by pulsed glow discharge and study the ions with TOF-MS Ar plasma Anode Cathode CsI particles ions TOF detector Cs + I+I+ High energy electrons Pre-peak Fragmentation Penning ionization Soft, ( CI ) After peak

3. time Pulsed Glow Discharge Synchronized with TOF repeller 0 20  s Discharge pulse, Ionization 0 - 300  s Repeller of time of flight Will send a packet of ions to detector f = 100 -1000 Hz

4. Experimental Setup TOF GD Solution of A salt (NaCl)

5. skimmer TOF detector ions Argon flow carrying particles cathode Anode sleeve pump Insulator Argon flow Discharge source: Pressure gauge

6. Cs + I+I+ Ar 2 + Brass 85 Rb +, 87 Rb + Cesium Iodide (2.5mM) and Rubidium Iodide (7.5mM) Intensity (mv) Mass / charge (amu)

7. Na + Mg + Ar +, ArH + Cl + O2O2 N2N2 H2OH2O Sodium Chloride (17mM) and Magnesium Nitrate (16mM) Repeller delay time = 56  sec Intensity (mv) Mass / charge (amu)

8. skimmer ions cathode Anode sleeve pump Insulator Pressure gauge Problems: -Can not increase the flow -Clogging at needle valve as a result -Particles pass very fast -Signal was not reproducible Corrosion (sputtering)

9. cathode Anode Insulator Changing the anode design (anode C) AnodeCathode + Increases the residence time for particles + Higher flows allowed (500, instead of 150 ml/min) -Reduces the ion transfer yield

10. A2 Signal intensity (mv) Repeller delay time (  s) C2 B2 20 40 60 80 100 Ar = 40 ArH = 41 Cu = 63 Comparing Anodes No particle Only argon

11. Signal intensity (mv) Repeller delay time (  s) Ionization of CsI particles Nebulized from 10mM CsI solution (Anode C) Max Cs+ signal at 58-60  s

12. Signal stability study (Cs) Repeller delay is fixed at 58  s Integ time = 3s 2mM 1 mM 0.5mM 0.1mM Collection time (0-14min)

13. Cathode after ionization with anode C

14. Signal intensity (mv) Repeller delay time (  s) Penning ionization Ar = 40 ArH = 41 Cu = 63 Argon only, through the back sleeve Max sputtered?

15. cathode Anode Insulator Ideal design! AnodeCathode + Allows more residence time for particles + Higher flows allowed (500, instead of 150 ml/min) + Argon back flow interacts with particles and increases their residence time, enhances ionization (Penning) *no more reduced ion transfer yield Argon flow

16. Anode Cathode (-) Argon in vacuum Particles emission Ionization study by emission spectroscopy Insulator detector

17. cathode Anode Insulator Laser ablation with anode C AnodeCathode laser

18. Laser Laser Ablation mirror Lenz

19. Time Intensity (mv) Power supply on 240 sec 0 sec Laser on 63 Cu signal by time in successive spectrums (Transient mode) = 240 mass specs