1. National Research Nuclear University MEPhI, Moscow, Russia
Results of the deuteron trajectory reconstruction in the PAMELA experiment
Koldobskiy Sergey A.
National Research Nuclear University MEPhI, Moscow, Russia
Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

2. PAMELA Experiment
Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

3. Deuteron analysis results
Results of deuteron spectrum reconstruction for GCR and re-entrant albedo particles have been published already and can be found in the following works:
Adriani, O., Barbarino, G.C., Bazilevskaya, G.A. et al., Astrophysical Journal, 2013, V.770 (1), p. 2.
Koldobskiy, S., Adriani, O., Barbarino, G.C., et al., Bulletin of the Russian Academy of Sciences: Physics, 2015, V. 79 (3), pp
Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

4. Deuteron identification
The deuteron identification procedure is based of multiparameter correlative analysis of signals from tracker and ToF system. Values of particle rigidity, velocity and multiple measurements of energy losses are used. The identification procedure was updated in comparison to the procedure used for deuteron spectrum reconstruction, because if we want to reconstruct trajectories we need to know that every considered into account event is a deuteron. So stricter cuts was used. Data sample from July 2006 to January 2008 was used and more than deuteron events with energy from 100 to 400 MeV/nucleon were selected.
Rigidity, GV ΔE
Deuterons
Protons
Number of events
1/β
Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

5. Track reconstruction routine
Each selected deuteron event was backtraced from the registration point. Track reconstruction was done on basis of known particle rigidity, point of registration, vector of particle motion by solving particle motion equations with numerical integration methods implementing International Geomagnetic Reference Field Model (IGRF) as internal geomagnetic field model. Trajectories were traced until: 1. they reached the boundaries of Earth’s magnetosphere during backtracing; these particles were classified as GCR d; 2. they intersected the boundaries of “dense” atmosphere, which was assumed at an altitude of 30 km; these particles were classified as re-entrant albedo deuterons; 3. they survived more than 10 seconds and fulfill adiabatic conditions; these particles were classified as d of radiation belt.
Examples of reconstructed deuteron trajectories
x, ×1000 km
z, ×1000 km
y, ×1000 km
Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

6. Coordinates of GCR d registration
Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

7. Re-entrant albedo I lifetime >10 sec Lifetime for albedo particles
Example of long-lived d trajectory (9.8 sec livetime) generated in the East of SAA
So there is two types of re-entrant albedo deuterons:
short-lived;
long-lived.
Short-lived d adsorbs quickly by atmosphere.
Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

8. Re-entrant albedo II
Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

9. Re-entrant albedo II
Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

10. Radiation belt deuterons I
The typical trajectory of RB deuteron
Rigidity composition for deuterons in RB
x, ×1000 km
y, ×1000 km
Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

11. Radiation belt deuterons II
85 – 140 MeV/n
140 – 215 MeV/n
215 – 300 MeV/n
Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

12. Conclusions
Trajectory reconstruction was done for deuterons registered in PAMELA experiment with energies from 80 to 400 MeV/nucleon for a first time. Three populations of deuterons are clearly distinguished: GCR, albedo, trapped particles. Subpopulations of albedo deuterons are observed: short-lived splash, long-lived quasitrapped and psedotrapped (penumbra) particles. Results for deuterons are close to PAMELA results for protons (Geophys. Journal-Space 2015).
Koldobskiy S. A. // October 10, 2015 // ICCPA2015// Hotel Milan, Moscow, Russia

13. Thank you for attention