To calibrate the DSSSD detector a triple-alpha source is mounted on a linear drive (see Fig.1) just upstream of the final slit box.
Source ID: R-00869
Radionuclides: 239Pu, 244Cm, 241Am
strength: 2.87 kBq
The IN postition is at 85 mm (see Fig.2).
The measured intensities both in the IC and on the DSSSD are slightly less than 0.5/s. The IC has to be operated at >50 Torr for sufficient stopping power for an alpha calibration run.
Since spring 2018, we have the option to install a fission source instead of the alpha calibration source to test and setup the MCPs offline.
The IN position for the fission source is all the way in.
Source ID: R-01156
Radionuclides: Cf-252
Quantity: 3.19E+04 Bq on 1-Jul-14
In order to install the fission source, follow the procedure to slowly venting the FSB with nitrogen and remove the linear drive to switch sources.
Verify whether a swipe and work permit are required before opening the beamline.
Whoever handles the sources has to complete radiation source training beforehand.
Wear gloves when handling the radioactive sources and be extremely careful not to touch the surface of any of the sources.
Remove the alpha source holder (Fig. 3) and store the alpha source in the source safe, while it's not in use.
The back of the fission source (Fig. 6) is threaded, making it easy to simply use a screw to attach the source on the linear drive (see Fig.5).
Once the fission source is securely attached (Fig.7), re-install the drive (make sure to use a new copper gasket) and close up the beamline.
Attach the corresponding calibration source sign on the drive.
Follow the procedure for slow pump down of the FSB. Do not leave the MCPs on air over night.
Fig.1 - Linear drive.
Fig.2 - Linear drive IN position for triple alpha source.
Fig.3 - Triple alpha source mounted on end of linear drive.
Fig.4 - Picture of alpha source looking upstream.
Fig.5. - Picture of alpha source looking upstream with MCP0 foil in beamline.
Fig.6 - 252-Cf fission source.
Fig.7 - 252-Cf fission source mounted on linear drive.
