Delivery Ring Abort B. Drendel 3/17/14

Abort Dump Location The AP2 line will stay as-is between the present IQ29 and the Debuncher. This includes all magnets and instrumentation. Just upstream (aborted beam direction) of IQ28, we will put a horizontal trim, a vertical trim and a rolled dipole (ABV2 in drawing). The rolled dipole is an MDC and redirects the beam line to the center of the aisle (both horizontally and vertically). This magnet will need to be moved into the tunnel. We will move AP2 line toroid Tor724 to near the end of the abort line. We will add a SEM from our spares to near the end of the abort line. The abort line will have a vacuum window or blank at the end. We will move ion chamber IC728 to between the vacuum window and the abort dump.

Delivery Ring Abort Tunnel Location The abort dump is located just upstream of where the the brown AP2 line shielding is currently. The AP2 line brown shielding will be used as the abort dump. It will be moved by iron workers from it's current location, upstream about 12' and moved to the center of the aisle both horizontally and vertically. It will be stacked on top of concrete to get the right height. The egressway will be blocked by the abort dump. Fencing will be put up to cover any gaps between the abort dump and the tunnel walls. New safety system mini loops will be installed on both the transport side and Debuncher side of the abort dump due to safety rules about length of allowed dead ends in tunnels. One mini-loop will be on the Debuncher/Muon Rings enclosure side and the other on the beam transport side. The AP2 transport gate does not move. The Pbar 95 LCW runs overhead down the AP2 line from the Debuncher and ends at the AP2 "left bends." The last element that will need LCW cooling is the rolled down bend. The LCW piping can be cut and capped after that. There are signal cables in the cable tray that runs along the left wall of the AP2 line enclosure (facing the direction of aborted beam). This will need to remain intact as those cable trays carry Controls and Abort links from AP50 to AP0. Everything from the downstream face of the abort to the future M2/M3 line merge can be removed. The mini-loop area between the downstream face of the abort to the transport gate can be used for storage. Rad levels will be only a couple mr/hr at most according to MARS simulations.

Beam Assumptions Horizontal emittance 30 pi-mm-mr Vertical emittance 4 pi-mm-mr (double injected beam size) 6σ transverse beam size (99.7% of gaussian) Vertical dispersion displacement added to transverse size (conservative, instead of adding in quadrature) Black ellipse is upstream beam size, red downstream Trims are ignored (should have adequate aperture) J. Morgan

Lattice functions J. Morgan

Abort Beam Numbers Maximum single pulse rate = 1E12 protons/pulse Expected Rate = 5E11 protons/sec – Expected rate = abort clean up + permit trips + safety margin Abort clean up (assume 5% leftover) = [2 batches x 4E12 x 0.05]/1.33 sec = 3E12/sec Permit trips (one per minute max) = ([1E12] protons/min) / (60 sec/min) = 1.67E10 Safety margin 58% (chosen to even out numbers) Power = [5E11 protons/sec]x[8E9 eV]x[1.6E-19 J/eV]x[1KW/1000W] = 0.64 KW Yearly rate (assume 80% uptime) = [5E11 protons/sec]x[31,536,000sec/yr]x[0.80] = 1.26E19 protons/yr

In the center of the steel shielding is a 6"x 6" hole where the AP2 beam pipe runs. This hole will be filled with steel. The steel to fill the hole will need to be moved into the tunnel. The abort dump will be surrounded by concrete blocks as shown in the attached pictures. The concrete blocks will need to be moved into the tunnel.

MARS Runs Last MARS simulations were ran Fall ap.fnal.gov/users/rakhno/mu2e/absorber_debuncher_AP2_line/ 2012/ver_August/ Igor Rakhno completed the MARS runs – Igor is not available for further MARS runs this spring. Kaman Vaziri completed the calculations.

Hadron Flux Igor Rakhno

Hadron Flux Igor Rakhno

Average Flux The flux averaged over the volume of the air in this part of the tunnel is approximately 3.3E-7 (cm^-2 proton^-1) which, at 5E11 proton/sec, is equal to 1.65E5 (cm^-2 sec^-1).

Star Density Igor Rakhno

Star Density Igor Rakhno

Ground and Surface Water The highest level in the soil is 2.9E4 star/(cm3*sec). It is for 5.E11 proton/sec. We can definitely see the top- bottom star density asymmetry in the elevation view. If the sumps run only once a year, the concentrations of the radionuclides in the discharge will be about 40% of that allowed for surface water. However, if the sumps run once a month, the combined concentrations will be about 3% of the surface water limit. For the groundwater after 10 years of operation of this absorber, the ground water concentrations will be eight orders of magnitude less than the groundwater limit. Kaman Vaziri

Residual Dose Igor Rakhno

Residual Dose Igor Rakhno

Residual Dose Numbers Maximum residual dose on the front face of the dump is in the ballpark of 1mSv/hr (100mrem/hr). Maximum residual dose on the sides in the gap between concrete and the tunnel walls were slightly higher, but the front and back faces of the dump will be fenced off to prevent human access to these areas. The residual dose on the back face of the dump is only and 0.01 mSv/hr ( mrem/hr).

Tony’s Concern The muon campus shielding assessment (beams doc.db at 4513-v2) shows that the cleanup abort design is insufficient. The normal dose rates for a 400 watt steady state operation is about 100 mrem/hr at the berm surface. That could work according to the FRCM if we wanted to put a large area fence on the berm at the 40 arc. That’s really not such a good idea in my opinion. The dump design should be redone to get dose rates on the berm down to more reasonable levels. T. Leveling

Supplimental Slides

Magnet operating currents Septum – Approximately 25,000 Amps Q405 (SQE) – 1,570 Amps (2004 Collider lattice) Q733 (SQE) – 340 Amps (395 Amps in Run II) Q732 (SQE) – 340 Amps (368 Amps in Run II) Q731 (SQD) – 340 Amps (343 Amps in Run II) V730 (CDC) – 1,135 Amps (Same in Run II) Q730 (SQD) – 400 Amps (410 Amps in Run II) Q729 (SQD) – 400 Amps (411 Amps in Run II) Vnew (MDC) – 715 Amps J. Morgan