Single Event Effects Library

NOTICE

Ion species availability is limited until maintenance on the EBIS ion source concludes in mid 2025. Contact NSRL staff for information and updates.

The majority of Single Event Effects Library beams are not available while EBIS is offline. Please refer to the beam availability page of this guide for a list of the current library beams.

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In an effort to both make the process of performing electronics testing at NSRL more efficient and to reduce the amount of preparation time needed per user, a library of 74 beams has been developed that spans the accelerator’s energy range for all readily available ion species. This set of beams is called the “Single Event Effects Library” which is often abbreviated as “SEE Library” or “SEELib”.

For each ion species, the energies of these beams have been spaced in a way that allows intermediate energies to be reached by slowing the beam with a polyethylene degrader system. Generally less than 10 mm of polyethylene is needed to reach intermediate energies, a thickness below the point at which any significant straggling or fragmentation effects are introduced.

All SEE Library beams are uniform “square” beams and are available in either 20×20 cm² or 7×7 cm² formats. Arbitrary rectangular beam spots can be achieved through collimation provided that any side does not exceed 20 cm in length.

The use of the SEE library beams has the advantages of requiring less per-experimenter development time, allowing for on-the-fly changes to the experiment in response to real time results, and reducing energy change times from a few minutes to a few seconds.

While the library was initially designed specifically for LET-based single events testing (as the name suggests), it has since become the standard beam library for non-radiobiology experiments at NSRL. Unless there is a compelling reason to do otherwise, the SEE library should be used for any physics or electronics testing experiment even if an LET-based test isn’t being performed.

Single Event Effects Library Beam List

The table below shows the beams (ion species and energies) that are in the current, spring 2025, Single Event Effects library.

The energies in the above table denoted with an asterisk represent “high charge state” ions from the source machine. These ions can be accelerated to higher energies at the cost of greatly reduced intensity.

The figure below is an LET versus range plot which shows the regions that are covered by beams from the SEE Library.

SEE Library base energy beams are represented by larger colored dots. The energies that can be achieved by slowing the primary beams by using the small binary filter are represented by smaller colored dots. The full energy capabilities of the accelerator for those ion species are shown as light gray curves. All SEE Library ion species are depicted apart from hydrogen so as to show more detail on the high-LET side of the chart. Since the polyethylene degrader system functions in steps of 0.1 mm, the noncontinuous nature of the degrader thickness can be seen towards the low energy range.

The figure below is a simpler chart showing the energy range that can be covered from a each base energy and the small binary filter.

Example LET Testing Plan

The table below shows an example of how one might use SEE library beams to create a test plan that hits specific LET targets. The experimenter would use base energy beams and calculate—with for example the NSRL StackUp tool—the amount of polyethylene required to achieve a desired energy or LET at a particular region in their device. This example assumes a bare silicon surface will be the region of interest for the test, which is almost never the case in reality. It is an experimenter’s responsibility to account for their own particular part stack up.

Surface LET in Si [MeV-cm²/mg]	Ion Species	SEE Library Base Energy [MeV/u]	Poly. Degrader Thickness [mm]	Energy at Sample [MeV/u]	Range in Si [mm]
0.1	12C	300	0.0	300	93.92
0.5	28Si	370	0.0	370	55.43
1	48Ti	500	0.0	500	63.10
2	56Fe	285	3.5	270	19.73
3	56Fe	190	8.1	142	6.74
4	93Nb	420	0.6	417	26.65
5	93Nb	300	4.7	270	13.28
6	93Nb	240	5.5	199	8.06
7	107Ag	260	1.5	246	9.97
8	107Ag	260	6.3	197	6.95
9	107Ag	173	0.8	163	5.09
10	159Tb	446	8.9	381	16.81
12.5	159Tb	290	4.7	247	8.51
15	181Ta	310	3.3	278	9.26
20	209Bi	330	5.1	273	8.06
25	209Bi	211	2.2	180	4.22
30	209Bi	147	1.0	130	2.59
35	209Bi	147	2.6	100	1.75
40	209Bi	147	3.5	79	1.24
45	209Bi	147	4.1	64	0.92
50	209Bi	147	4.5	53	0.70
55	209Bi	147	4.8	44	0.55
60	209Bi	147	5.0	36	0.44

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