====== ChipIr ======
 
===== References =====
  * [[https://www.isis.stfc.ac.uk/Pages/Chipir.aspx#:~:text=ChipIr%20is%20a%20new%20beamline,the%20Rutherford%20Appleton%20Laboratory%2C%20UK.|Facility Page]]
  * {{ :facilities:irradiation:chipir:cazzaniga_sipm_conference_25april2022.pdf |Presentation}}

===== Beam Parameters =====
 
^ Beam Source ^ Particle Type ^ Flux ($cm^{-2} s^{-1}$) ^ Energy ^ Notes ^ 
| Proton Spallation | neutron | $5\times 10^{6}$ | 10-800 MeV| | 

===== Facility =====

ChipIr is a beamline at the Rutherford Appleton Laboratory. It was designed for the purpose of studying single event upsets (SEE) of microelectronics. The studies are performed with neutrons whose spectrum resembles that of atmospheric neutrons. The intensity can be increased by a factor up to $10^{9}$ depending on the configuration.

Neutrons are produce by accelerating protons up to 800 MeV. These are then injected into a tungsten target, producing secondary neutrons. Through hydrogenous moderators to a variety of instruments the neutron spectrum simultaneously includes thermal and cold  neutrons. The fast neutron beamline is extracted through the addition of a new channel in the beryllium reflector. Neutrons from this channel illuminate a secondary scatterer made to optimize the hard atmospheric-like neutron spectrum. With an independent shutter the neutron beam can be closed and opened while the accelerator is running. The schematic is shown below. 

{{ :facilities:irradiation:chipir:chipir_schematic.png?direct&800 | Schematics of the components needed to produce the atmospheric neutron beam. }}

===== Neutron Spectrum =====

The resulting neutron spectrum look like the figure below.

{{ :facilities:irradiation:chipir:neutron_spectrum.jpg?direct&800 |ChipIr neutron spectrum}}

===== Beam Profile =====

The collimator system provides flexibility with respect to the beam size. The beam size ranges from 1m x 1m down to a few $cm^2$. The figure below shows the beam uniformity profile for a beam size of 70mm x 70mm (typical order of magnitude for electronics size). As shown below, the beam is mostly uniform within the 2% level.

{{ :facilities:irradiation:chipir:beam_profile.jpg?direct&600 |Map of the 70 × 70 mm2 ChipIr beam measured with a Diamond Detector}}