Laser plasma accelerated ultra-intense electron beam for efficiently exciting nuclear isomers

Abstract

Utilizing laser plasma wakefield to accelerate ultra-high charge electron beam is critical for many pioneering applications, for example to efficiently produce nuclear isomers with short lifetimes which may be widely used. However, because of the beam loading effect, electron charge in a single plasma bubble is limited in level of hundreds picocoulomb. Here, we experimentally present that a hundred kilo-ampere, twenty nanocoulomb, tens of MeV collimated electron beam is produced from a chain of wakefield acceleration, via a tightly focused intense laser pulse transversely matched in dense plasma. This ultra-intense electron beam ascribes to a novel efficient injection that the nitrogen atom inner shell electrons are ionized and continuously injected into multiple plasma bubbles. This intense electron beam has been utilized to exciting nuclear isomers with an ultra-high peak efficiency of 1.76 × 10 15 particles/s via photonuclear reactions. This efficient production method of isomers can be widely used for pumping isotopes with excited state lifetimes down to picosecond, which is benefit for deep understanding nuclear transition mechanisms and stimulating gamma-ray lasers.

Micro-size picosecond-duration fast neutron source driven by a laser–plasma wakefield electron accelerator

“…2(d), the average charge is 15.59±1.68 nC. We have found that a large amount of electrons are ionization injected [48] into over ten plasma bubbles, which results in that the total beam charge can be increased about ten times higher than the usually LWFAs, the details see in Ref [49] .…”

“…Because the 27 TW tightly focused laser pulse is difficult to self-focus in low-density plasma, when the plasma density increases to 3.68×10 19 We have found that a large number of electrons are ionization injected [48] into over 10 plasma bubbles, which means that the total beam charge can be increased about 10 times higher than the usual LWFAs; for details see Ref. [49].…”

Experimental study of medical isotopes 62,64Cu and 68Ga production using intense picosecond laser pulse

“…A Joule-class, fs laser system operating at 100 Hz and even higher would be available in the near future [12]. Here, we show four typically experimental cases that produce relatively large charge e − beam by using fs lasers: Q e ∼ 0.2 nC and T e = 6 MeV produced with 1.1 J and 28 fs laser pulse (Case 1) [33], Q e ∼ 5.4 nC and T e = 10 MeV obtained with 3.2 J and 45 fs laser pulse (Case 2) [34], Q e ∼ 1.0 nC and T e = 12.5 MeV generated with a 14 J and 45 fs laser pulse (Case 3) [35], and a quasi-monoenergetic 300 MeV e − beams with Q e ∼ 0.5 nC generated by a 2.5 J and 30 fs laser pulse (Case 4) [36]. Note that the above Q e is calculated for electrons with energy higher than 8 MeV, below which the electrons are hard to trigger photonuclear reactions, as mentioned above.…”

“…Note that the above Q e is calculated for electrons with energy higher than 8 MeV, below which the electrons are hard to trigger photonuclear reactions, as mentioned above. In order to prospect the production of medical isotopes driven by such lasers, the achievable activities of 62,64 Cu and 68 Ga are calculated using three typical cases of e − beam parameters [33][34][35][36] and laser repetition rate of 100 Hz. Figure 9(b) shows that in Case 2, the achievable activity is expected to be 0.2 GBq for 62 Cu, 0.1 GBq for 64 Cu and 0.05 GBq for 68 Ga, which reaches the activity level for clinical PET (0.1-0.5 GBq).…”

“…However, such shot-to-shot variations were not investigated in the experiment due to the limited number of laser shots. Recently, Feng et al [34] studied the e − beam instability using a 45 fs, 3.2 J laser pulse for ten laser shots. The shotto-shot variation in T e is ∼18% and the one in Q e is ∼10%.…”