1. Delayed X- and Gamma-Ray Line Emission from Solar Flare Radioactivity V. Tatischeff, B. Kozlovsky, J. Kiener and R. J. Murphy ApJS, submitted  Proposed by Ramaty & Mandzhavidze (2000, IAU Symp.)  size and development of the radioactive patch  mixing and transport processes in the solar atmosphere  the most promising delayed line is at 847 keV from 56 Co decay

2. Selection of the Radioisotopes 10 min <T 1/2 < 77 days 21  + -emitters (KLR87 + KMS04) + 7 Be, 24 Na, 56 Mn, 58 Co m Updated cross sections for the production of 34 Cl m, 52 Mn g, 52 Mn m, 55 Co, 56 Co, 57 Ni, 58 Co g, 60 Cu and 61 Cu by p,  and 3 He reactions

3. Radioisotope Production Cross Sections TALYS calculations Data: Michel et al. (1997) x10 -2 x10 -4 x10 -6  Experimental reaction data from EXFOR http://www.nndc.bnl.gov/exfor/ http://www.nndc.bnl.gov/exfor/ + Theoretical estimates from EMPIRE-II (version 2.19), TALYS (version 0.64), and the "Silberberg & Tsao" code above ~250 MeV (cosmic-ray physics)

4. Radioisotope Production Yields  Thick target interaction model with nuclear destruction and catastrophic energy loss (e. g. pion production) of the fast ions (interactions between fast and ambient heavy ions are negligible)  Power law source spectrum up to 1 GeV/nucleon, with s=3.5, 2 and 5  Impulsive-flare composition from SEP, with  /p=0.5 and 3 He/  =0.5

5. Delayed line emission 30 min after the end of the flare  Unexpected strong lines at 1434 keV from 52 Mn m, 1332 and 1792 keV from 60 Cu, 6.92 (Co K  ) from 58 Co m (E x =25 keV) + 57 Ni, 2127 keV from 34 Cl m... *Normalized to a fluence of 300  cm -2 emitted in the sum of the 4.4 and 6.1 MeV prompt narrow lines (2003 Oct. 28 flare) *

6. The experimental proof

7. Delayed line emission 3 h after the flare  The strongest line after that at 511 keV can be the neutral Co K  line  Photoelectric attenuation: at solar depths of 10 -3 –10 -1 g cm -2 (low chromosphere), the optical depths of 6.92 keV X-rays are ~ 10 -3 –10 -1  X-ray imaging of the radioactive patch ? *Normalized to a fluence of 300  cm -2 emitted in the sum of the 4.4 and 6.1 MeV prompt narrow lines (2003 Oct. 28 flare) *

8. Delayed line emission 3 days after the flare * Time dependence of the 511 keV line  From ~1 to ~14 hours, the main source of the positrons is 18 F, which can be mainly produced by 16 O( 3 He,p) 18 F  Measurement of the 511 keV decay curve can provide the accelerated 3 He abundance

9. The influence of the accelerated ion composition Reames (1995) 3 He/ 4 He H/ 4 He Reames et al. (1994) ?  SEP composition for fast C and heavier elements relative to  -particles, but with  /p=0.5 (   –  line in  -ray flares, SM97...)  Strong enhancement of the fast heavy elements, with e.g. A Fe /A p =137 n Fe /n H  The delayed lines will measure this enrichment

10. The Gamma-Ray Imager … an artist’s Cosmic Vision From J. Knödlseder, ESLAB Symposium 2005