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Message ID: 25     Entry time: Fri Jun 9 13:47:24 2023
Author: Lucia B, Carlo B 
Subject: LNL1 

We performed the scan on the LNL1 23Na target (details in the excel sheets in previous entry) for the E_p=309 keV resonance. The target has a sharp well defined rising edge, but it quickly deteriorates under beam bombardement (already after 0.1 C we can see the plateau height at same energy decrease). The thickness of the target also appears much larger than what recorded in the target info.

During the night between 8th and 9th June, we left a long run. In the morning we found the Faraday Cup closed and a pressure of a few mbar in the target chamber. We noticed one of the tubes of the chiller was open on the ground. This caused the chiller to stop working around 9pm. The target started to heat up and the tantalum was bent towards the chamber.

We did not find water in the chamber, it was probably spread on the ground before the chiller stopped working. Possibly a microscopic fracture was formed in the backing, causing air to flow inside the chamber and worsening the vacuum. The turbopump was however still on and does not seem damaged.

Pictures of the target before and after beam bombardment are attached.

 

Attachment 1: 1686234338228.jpg  2.898 MB  Uploaded Fri Jun 9 14:55:20 2023  | Hide | Hide all
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