Wir schaffen Wissen heute für morgen. Paul Scherrer Institut Patrick Steinegger Diamond Detectors for Fast Transactinide Experiments

Transcription

1 Wir schaffen Wissen heute für morgen Paul Scherrer Institut Patrick Steinegger Diamond Detectors for Fast Transactinide Experiments PSI, 19. Dezember 212

2 Outline Introduction to transactinide chemistry The COLD thermochromatography setup and resulting deposition patterns Detector heating experiments Problems with common Si PIN-diodes and diamond detectors in a future IVAC setup PSI, 19. Dezember 212 Seite 2

3 Transactinide chemistry experiments We are interested in the chemical properties of transactinide elements (Z > 13) with a special focus on the so-called superheavy elements (SHE). For instance, this is achieved by deducing adsorption enthalpies (- H ads ) using the thermochromatography setup with the Cryo OnLine Detector (COLD). T = 35 C T = -18 C Detector array I. Zvara, Isotopenpraxis 26 ( 199 ) 6, pp PSI, 19. Dezember 212 Seite 3

4 Schematic experimental setup Decay properties of SHE Fl (114) (observed at FLNR in 24 [1]) [1] Y. Oganessian et al., Phys. Rev. C 7 ( 24 ) [2] R. Eichler et al., Nature 447 ( 27 ), pp [2]

5 The COLD Array PSI, 19. Dezember 212 Seite 5

6 Deposition of 185 Hg and 219 Rn along COLD Higher temperatures would enable the determination of adsorption enthalpies of elements with even higher adsorption characteristics on gold (e.g. 113, Tl, Hg, Pb, etc. e.g. 8 diamond sandwich detectors in the COLD array for the hot region ). Rel. yield / detector [%] Monte Carlo Simulation 185 Hg (- H ads > 47 kj/mol) 219 Rn (- H ads = 19 kj/mol) Temperature [ C] Detector # Temperature limitation at T max 4 C PSI, 19. Dezember 212 Seite 6

7 Deposition of Cn (Element 112 ) Hg gold (-28 C) ice 219 Rn gold ice Cn Rel. yield / detector, % Hg gold (-5 C) ice 219 Rn Temperature, C Rel. yield / detector, % Cn gold ice Temperature, C Hg gold (-21 C) (-39 C) ice 219 Rn (-124 C) gold ice Cn Detector # Detector # PSI, 19. Dezember 212 Seite 7

8 Detector under IR- Irradiation (Joule Heating) PSI, 19. Dezember 212 Seite 8

9 Detector under IR- Irradiation (Joule Heating) Pu room temperature 7 C 1. DBS (unpolished) DBS (polished) counts / channel Am 244 Cm counts / 5 channels (norm.) kev (1.3 %) 183 kev (3.6 %) Calibrated RT [ kev ] Energy [MeV] The shift to the right seems to be equidistant, which means that there must be an absolute charge amount in addition per incident particle. This can be either related to the charge collection distance or a constant charge release at higher temperatures. A spectrum of 148 Gd and 241 Am should give further insight in this effect (larger energy gap equidistant shift?). PSI, 19. Dezember 212 Seite 9

10 Vacuum chromatography Since diamond detectors can be operated near a hot source (e.g. oven), they are perfectly suitable for isothermal vacuum chromatography experiments: Heat source (e.g. resistance oven) Detector (cooled catcher) Read-out electron. The transition from gas chromatography towards vacuum chromatography has the following advantages: - No aerosol transport and therefore lower background (decreased random rate). - Less pollutions (organic impurities, water, etc.) clean stationary surfaces. - Better energy resolution in case of vacuum chromatography. - Easy to simulate with a MCS approach. PSI, 19. Dezember 212 Seite 1

11 Vacuum chromatography Since diamond detectors can be operated near a hot source (e.g. oven), they are perfectly suitable for isothermal vacuum chromatography experiments: Heat source (e.g. resistance oven) Detector (cooled catcher) Read-out electron. The transition from gas chromatography towards vacuum chromatography has the following drawbacks: - Less chromatographic resolution due to random walk in comparison with a geometrically identical thermochromatography setup. - Complicated coupling to production device (relative to the stopping; see thesis Dr. D. Wittwer). The need of positioning the detector near an IR, UV or VIS source or the operation in the vicinity of an oven (see also thermal release experiments T > 12 C) excludes common Si-based detectors and demands for diamond used as detector material. PSI, 19. Dezember 212 Seite 11

12 Isothermal Vacuumchromatography PSI, 19. Dezember 212 Seite 12

13 To be continued Detector ( Trap ) 252 Cf-Source Detector ( Trap ) IVC COLD ( VTC ) Target (? )

14 Thanks to /////////////////////////////// /////////////////////////////// /// /// /// Alex Vögele /// /// Andreas Türler /// /// Arnold Lücke /// /// Christina Weiss /// /// Dave Piguet /// /// Erich Griesmayer /// /// Ilya Usoltsev /// /// Robert Eichler /// /// Rugard Dressler /// /// Silvan Streuli /// /// /// /////////////////////////////// ///////////////////////////////

15 Thank you for your kind attention! PSI, 19. Dezember 212 Seite 15