Turkey s first photonuclear reactions performed at Akdeniz University: Matter, Anti-matter, Pure Energy and Alchemy

Transcription

1 (Ülkemizin ilk fotonükleer reaksiyonu Akdeniz Üniversitesinde gerçekleştirildi: Madde, Anti-Madde, Saf Enerji ve Simya) Turkey s first photonuclear reactions performed at Akdeniz University: Matter, Anti-matter, Pure Energy and Alchemy Haris Ðapo (Ismail Boztosun) Akdeniz University, Antalya IZYEF 2013 Izmir, September 2013

2 Outline 1 Introduction 2 Method and setup 3 Results 4 Summary and Outlook

3 Outline 1 Introduction 2 Method and setup 3 Results 4 Summary and Outlook

4 Introduction Photonuclear reactions photonuclear reactions describe a set of interactions between nuclei and photons, most commonly separation of either from the nucleus since the realization that nuclei are not fundamental point-like particles (In 1932, James Chadwick discovered neutron) the possibility of removing a neutron or a proton from nucleus arose separating a neutron of a proton from stable nucleus requires several MeV of energy (one commonly needs 10 MeV) producing a photon of 10 MeV energy took few decades most commonly the start of photonuclear reactions is associated with construction and operation of SLAC (Stanford Linear Accelerator Center) in 1960 s

5 Intro Nucleide Map Setup Results Summary

6 Photonuclear reactions Various cases photonuclear reactions change one element into another (Alchemy) if a neutron is removed a proton rich nucleus is created and it decays via β + decay back to valley of stability β + decays produce positrons and characteristic anhilation peak at mass of electron of 511 kev is observed (Anti-Matter) proton rich nuclei are not accessible via neutron absorption if proton is removes a neutron rich nucleus is created and it decays via β if photons is absorbed a metastable stable version of the same element is created

7 Photonuclear reactions in detail Generic Zinc example γ + N Z A N 1 Z A 1+n γ + N Z A N 1 Z A 1 + n γ + N Z A N Z A 1+p γ + 64 Zn 63 Zn+n γ + 70 Zn 69 Zn + n γ + 68 Zn 67 Cu + p

8 Outline 1 Introduction 2 Method and setup 3 Results 4 Summary and Outlook

9 Experiment stages Shot description first the sample is irradiated in the linac at the Akdeniz University s hospital sample is transported from the hospital to the physics department irradiated sample is counted in a detector counts are stored at appropriate time intervals once the counting is finished, background subtraction is performed background subtracted spectrum is analyzed peak by peak transition energies are obtained at this point counts from each peak are correlated with the time stamp a fit of counts vs. time is performed half-life is obtained at this point

10 Photonuclear reactions with linear accelerators LINAC linear accelerators can produce photons by bombarding a Tungsten, or and high-z, target with electrons photons are than produced trough bremssthralung and have the characteristic spectrum on the right: bremssthralung spectrum with 18 MeV end-point energy

11 Linear accelerators clinac photonuclear experiments involving linacs are routinely performed around the world but the use of clinical linac(clinac) for this purpose is a novel concept modern clinac found in radiation treatment facilities are capable of producing bremsstrahlung photons with endpoint energies up to 25 MeV and compare well to specialist setups such as S-DALINAC at TU Darmstadt or ELBE at Forschungszentrum Dresden in Rossendorf for the most part photonuclear measurement are not included in NUDAT, especially so for intermediate mass nuclei 1 1 pioneering experiment on gold: P. Mohr, S. Brieger, G. Witucki, and M. Maetz, Nucl.Instrum.Meth. A580, 1201 (2007),

12 Our linac setup Philips SLi-25 current end-point energy is 18 MeV, although linac can operate at lower energies as well in the future we plan to bring online 25 MeV end-point energy primary electron beam is generated by a gun with an energy of 50 kev electrons are accelerated in a copper cavity by a 30 GHz radio-frequency with peak power of about 5 MW steering and focusing of the beam is achieved by standard magnetic and electrostatic devices beam current is 30 µa for 18 MeV once collimated and flattened at a distance of 100 cm, the maximum area covered by photons is cm 2

13 Linac schematic

14 The detector High Purity Germanium Detector(HPGe) p-type, coaxial, electrically cooled, HPGe gamma-ray spectrometer with 40% relative efficiency and 768 ev FWHM at 122 kev for 57 Co and 1.85 kev FWHM at 1332 kev for 60 Co samples and the detector, were placed into a well-shielded cavity the detector is connected to the usual Nuclear Instrumentation Module for data acquisition calibration was performed with a source supplied by the Çekmece Nuclear Research and Training Center detector was configured with 8192 channels and the resulting energy resolution was kev (currently channels and kev resolution)

15 Full reactions Generic γ + N Z A N 1 A 1+n Z N 1 Z A 1 N Z 1 A 1 + e + +ν N Z 1 A 1 N Z 1 A 1+γ N 1 Z N Z 1 N 1 Z γ + N Z A N 1 A 1 + n Z A 1 N 1 A 1+γ Z γ + N Z A N Z 1 A 1+p N 1 A 1 A 1 + e + ν Z A 1 N 1 A 1+γ Z Zinc example γ + 64 Zn 63 Zn+n 63 Zn 63 Cu + e + +ν 63 Cu 63 Cu +γ γ + 70 Zn 69 Zn + n 69 Zn 69 Zn+γ γ + 68 Zn 67 Cu + p 67 Cu 67 Zn + e+ ν 67 Zn 67 Zn+γ γ + 66 Zn 65 Zn+n 65 Zn 65 Cu + e + +ν 65 Cu 65 Cu +γ

16 The observations The description of detection A stable element is exposed to linac gamma-rays. A radioactive element is produced. The element decays trough gamma or beta decay. Gamma decay is directly observed. In case of beta decay daughter nuclei are created in excited states and than the daughter decays trough gamma-decay to its ground state. The time-dependance of decay is linked to the half-life of the parent. In all cases only gamma-transition are observed. Notes in principle all nuclei go trough photonuclear reactions, but only those whose neighbor is radioactive can be observed in our setup in addition more practical restrictions apply, like: length of half-life, observability of daughter states, etc.

17 The analysis tool GF3 GF3 is a least-squares peak-fitting program designed primarily for use in analyzing gamma-ray spectra from Germanium detectors GF3 fits three components to each peak: a Gaussian, a skewed Gaussian and a smoothed step function to increase the background on the low-energy side the Gaussian, is the main component of the peak the skewed Gaussian, arises from incomplete charge collection the step function arises mainly from Compton scattering of photons into the detector and from escape of photoelectrons from the Ge crystal

18 Outline 1 Introduction 2 Method and setup 3 Results 4 Summary and Outlook

19 Cu-63 transition energies 10 4 t=2315 s t=700 s t=140 s t=2315 s t=700 s t=140 s 10 3 Counts per kev 10 2 Data NUDAT: ±0.05 kev; ±0.04 kev Our result:669.58±0.02 kev and ±0.02 kev E[keV] E[keV]

20 Zn-63 decay curve kev 962 kev fit(669),n 0 =27.4e3,λ=2.83e-3 fit(962),n 0 =14.2e3,λ=3.34e Net counts Data NUDAT: 38.47±0.05 min Our result: 40.8±0.6 min (669 peak) and 34.6±0.7 min (962 peak) t[s]

21 Zn-67 transition energies 10 5 t=86126 s t=23703 s t=4837 s t=86126 s t=23703 s t=4837 s 10 4 Counts per kev Data NUDAT: ±0.010 kev; ±0.010 kev 10 3 Our measurement: ±0.005 kev; ±0.23 kev E[keV] E[keV]

22 Cu-67 decay curve kev 300 kev fit(184),n 0 =98.8e4,λ=3.19e-6 fit(300),n 0 =3.3e4,λ=9.9e-7 Net area x Data NUDAT: 61.83±0.12 h Our result: 60.3±0.6 h (184 peak) and 197±73 h (300 peak) t[s]

23 Zn-69m and Cu-65 transition energies 10 5 t=86126 s t=23703 s t=4837 s t=86126 s t=23703 s t=4837 s 10 4 Counts per kev E[keV] E[keV] Data NUDAT: ±0.018 kev; ±0.004 kev Our: ±0.005 kev; ±0.008 kev

24 Zu-69m decay rate kev fit(438),n 0 =63.30e4,λ=14.23e Net area Data NUDAT: 13.74±0.02 h Our result: 13.51±0.03 h t[s]

25 Zu-65 decay rate kev fit(438),(n 0 *λ)= Net area Data NUDAT: ±0.09 days Only 1 day of observation is not sufficient for 244 day decay t[s]

26 Outline 1 Introduction 2 Method and setup 3 Results 4 Summary and Outlook

27 Summary The road so far photonuclear reactions with clinac are real possibility first experiment of photonuclear reaction performed in Turkey performed with local resources, staff and capabilities at the very first attempt data accuracy was reasonable and with every day we are getting better but the real testament to our achievement and a real summary is all the data we have gathered and shown

28 Summary The road so far photonuclear reactions with clinac are real possibility first experiment of photonuclear reaction performed in Turkey performed with local resources, staff and capabilities at the very first attempt data accuracy was reasonable and with every day we are getting better but the real testament to our achievement and a real summary is all the data we have gathered and shown What did not fit into the talk since may we have performed several new experiments on various nuclei Cu, Ni, Ti, Pb, In, Hg, etc. but the hard part, the data analysis is still pending

29 Outlook To be continued, stay tuned solve the systematic accuracy issue find new elements which would be best suited for future experiments upgrade the accelerator to 25 MeV (software issue) build an online multi detector setup capable of measuring (γ,γ ) reactions with new setup investigate the collective behavior of nuclei (GDR, PDR, etc.)

30 Our group Collaborators on this project: Ismail Boztosun,Haris Ðapo, Süleyman Fatih Özmen, Yiğit Çecen, Mesut Karakoç, Abdullah Çoban,Alp Cesur, Tanfer Caner, Edip Bayram, Gizem B. Keller, Beyza Kücük, Abdullah Güvendi,Melek Derman and Deniz Kaya

31 Thank you for your attention!