Ion Beam Lab

10:47 am - Switching Magnet

The switching magnet power supply is operational again. While troubleshooting the power supply, the unit started working. I have a possible candidate for the source of the problem, but can't follow that avenue until the unit fails again.

5:26 pm - Switching Magnet doesn't work

Today I tried to run the Ni irradiation, the beam current of 4.2mA was stable at Cup2.
But as I increased the switch magnet current, it stuck at ~11% and doesn't increases any more. So I turned it off and on again, it stopped working at all.

3:15 pm - gas cathode

Yesterday, Kim and I installed the 1500 L/s turbo on the SNICS. I ran the source today, and was able to achieve ~76 uA of stable H+ current for about 45 min on cup 1. The current jumped to more than 80 uA but fell back to the stable value. With this amount of current we could get 30-35 uA on the samples.

10:31 am - Switching Magnet Working

This morning Kim and I finished testing the magnet and everything is working. However, now when using the reversal button you must wait about 15 seconds before it actually reverses the current. Kim is going to talk to NEC to see if that is a problem, or a symptom to another problem.

4:01 pm - Switching magnet

I do not have the switching magnet power supply completely assembled yet. I want to test it again tomorrow morning before I finish putting it back together. I should be completed by late morning.

3:57 pm - Switching magnet

I have the switching magnet power supply working. I don't know if there is an intermittent problem that may surface again; or if either the stepper motor that controls the variac or the variac itself were jammed. I removed the stepper motor and rotated both the motor and the variac manually. After I re-assembled them, the unit worked.

3:25 pm - gas cathode

Finally some good news. Kim and I replaced the original 450 L/s turbo pump on the SNICS with a 1000 L/s turbo. I ran the source this afternoon, and was able to get -67uA of H+ on cup 1. If a sufficiently sized roughing pump is available I would like to try the 1500 L/s turbo as well.

4:25 pm - Switching Magnet Power Supply

Today I tried to run a RBS experiment, but when the beam got down to the switching magnet I couldn't bring up the power on the magnet. Kim and I tried to trouble shoot the fuses, but there is no noticeable problems. We will be contacting NEC and Walker Scientific to see if they may know what the problem is. If the Switching Magnet is down for an extended period of time we will proceed with the testing of the gas cathode. We'll post an update after talking with NEC and Walker Scientific.

6:27 pm - 0.5 dpa Irradiation Completed

The 500C 0.5 dpa irradiation of the TiN coated HT-9 samples is completed. The samples will be unloaded tomorrow, and then they will be counted next week. RBS will also be performed on them as well.

10:48 pm - TiN coated HT-9 Irradiation

The 0.5 dpa 500C irradiation of the TiN coated Ht-9 samples is ~68% completed. The cathode will be replaced tomorrow morning, and if it works well the irradiation should be completed tomorrow, or close to it.
So far the cathodes from batch A479 have only worked well after extensive conditioning. Each cathode has needed atleast 5 hours of conditioning to obtain a stable current of between 20-25 um on the stage.