G.Quarta
Irradiation of 3 x DLC from China (Magnetron Sputtering) + 1 virgin and 3 x DLC made in Lecce (PLD) + 1 virgin irradiated with 2 MeV protons reaching fluences of:
5 x 10^13 (~30 min) = 1.13MGy
5 x 10^14 (~30 min) = 11.3MGy
1 x 10^15 (~3h) = 22.6MGy
Not performed, would have taken too long:
5 x 10^15 (~15h)
Antonio Serra
No heavy structural changes observed
slide 3-4: going from pristine to 23MGy: no substantial (macroscopic) damages. Somewhat more pronounced changes in chinese DLC, but Piet confirms it is much older (even up to few years). Piet will try to look up when this DLC was produced and with which value of resistivity. Alfio provides info on Graphene irradiation: to obtain 700MGy he irradiated with 16MeV gold ions.
slide 5: for illustration only: graphene goes from crystalline to amorph structure (700MGy) and here one can see heavy structural damage. pictures taken with magnification of 500,000x, one can see structures of 2-3 angstrom
slide 6&7: Raman: 100nm penetration (dlc thickness = 100nm, graphene thickness > 100nm). Same behaviour observed for DLC (amorph carbon) and graphene (highly ordered). Immediate change at low dose followed by some "reconstruction". Check if this was observed already in literature. Maybe remake plots also in linear scale?
Conclusions:
- PLD foils are stable up to 23 MGy with values of Resistivity that remain the same, which is our main observable we are interested in.
- This work can be presented at conferences (both solid state, as part of a presentation on resistive gaseous detectors by Piet), we should look up in literature if the "reconstruction process" has been already observed and explained, if not also this might be an interesting work to think about.
Next work: irradiate 1-200MGy, with 2-3 species (H,He,C), 3 points of overlap. Deposit also 20nm DLC on glass.
1 deposit on Glass can be irradiated at 20MGy and analyzed, thereafter further irradiated.
Anna Paola will make:
- Kapton: 2 depositions => 2 x 4 campioni: 2x(3 per irrad, 1 virgin).
- Glass: 1 set di 4 small glasses in a single PLD run.
Piet will make a table with proposal for irradiation and send this to Gianluca for verification, eg:
C 2 MeV 45s 1MGy
C 2 MeV 5min 10MGy
...
Gianluca / Alfio will check if there were any pictures taken during the campain (samples in sample holder inside accelerator, tired shifters in control room, ...) that can serve in some future presentation.