Accelerator Update

Monday December 31
Operations monitored store #870. (A store consists of the colliding proton and antiproton particle beams.) The Antiproton Source (Pbar) stacked (collected antiprotons). The H- source suffered from multiple trips, which interferes with stacking. (Fermilab has two Preaccelerators called I minus and H minus. This is where the particle beam begins. Only one Preacc is used at a time. The other is kept in reserve.) At 9 AM a Pbar expert held off stacking for an hour while he worked on the stacktail cooling system. (The stacktail is the least dense region of the antiproton beam and where the beam is deposited. Stacktail cooling is the process of moving the antiprotons from the stacktail into the stack.) Booster personnel worked on a RF station during this time. (RF stands for Radio Frequency, which is the electromagnetic energy used to accelerate particles.) Operators investigated the breaker trips that had been occurring at F0 since Friday and discovered that the breaker's time delay may need to be changed. Experts weren't sure. (The TeV's four miles of tunnel is divided into six equal sections, A through F.) This breaker controls power for equipment in the P1 line, one of the Main Injector's (MI) transfer lines. The Duty Electrician said he needed an hour to investigate further. An expert installed an amp-meter to monitor the breaker's current. Pbar returned to stacking at 10:22 AM. At 2 PM Operation terminated store #870. Unfortunately the beam quenched at A48. (A quench refers to a cryogenic magnet going from a superconductive temperature of 4 Kelvin to normal. Absolute zero is zero Kelvin. One Kelvin is equal to one degree on the Celsius scale.) Various controls problems started around 7 PM and continued until near the end of shift. Apparently part of the controls system was having temporal issues dealing with leaving the old year. Operations established store #872 at 9:21 PM. Its initial luminosity was 5.75E30.

Tuesday January 1
Happy New Year. Operations monitored store #872. Pbar stacked. The H- source continued to trip. At 5 AM a Booster RF station tripped off and wouldn't reset. Operators bypassed the station. A LINAC expert switched the Preaccelerator back to the I- source. At 6:30 PM Operations terminated store #872 and again beam quenched at A48. Operations established store #874 at 11:19 PM. It had an initial luminosity of 8.7E30.

Wednesday January 2
Operations monitored store #874. Pbar stacked. At 3:30 AM a Control Power Chassis for Booster correction elements failed. Experts came in and had the problem resolved by 6 AM. Pbar then returned to stacking.

Today's Plans
Operations will terminate the store this morning and allow the Collider Detector Facility and D-zero to go in on a three-hour access to make equipment repairs.

Live Tevatron status