LENS Construction History

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February 2004
View of the LENS accelerator area looking south from the old cooler vault roofbeams. The cooler injector synchrotron (CIS), partially obscured by the roofbeams, is still assembled and in place.

April 2004
Same view as above with the roof beams above the old cooler injector synchrotron (CIS) removed. The entire CIS is removed as well.

May 2004
Same view as above with a new shielding wall between the proton accelerator and klystron gallery. (neither are in place yet). The accelerator will be placed to the left of this wall, and the klystrons will be located to the right.

Part of the LENS SANS (Small Angle Neutron Scattering) tank, donated by the University of Missouri, can be seen in the foreground.

June 2004
The PL-7, originally the injector for the CIS synchrotron ring, is moved into place. The PL-7 proton accelerator consists of two accelerating stages - a 3-MeV RFQ (radio frequency quadrupole) and a 4-MeV DTL (drift tube linac).

August 2004
The injector for the LENS proton accelerator in the development area. Pictured from left to right (in the larger image) are Andy Sebold, Bob Brown, and Ron Kupper.

August 2004
The PL-7 viewed from the roof beams of the old cooler vault, looking south.

August 2004
Dave Townsend connecting coolant lines to the Linac.

September 2004
Installation of the proton beamline begins. The orange components are quadrupole magnets used to focus the proton beam as it leaves the accelerator.

September 2004
Close-up of the end of the PL-7 proton accelerator showing two of the quadrupole magnets. The RF power is now attached to the DTL.

September 2004
Installation of the proton beamline continues. The yellow magnets are refurbished quadrupoles from the Cooler synchrotron.

September 2004
The LENS cryogenic moderator system under development in the LENS staging area.

September 2004
The LENS beamlines are surveyed in and their paths are marked on the floor with orange tape. The three paths in the foreground are the three LENS neutron flight paths. The point that they emanate from is where the moderator is located.

October 2004
The concrete pier that will support the LENS TMR (target/moderator/reflector) assembly is poured. In the foreground the radiation shielding around the TMR vault is taking shape.

October 2004
A view of the TMR vault. The finished pier for the TMR is shown on the left, and the support for the proton beamline is shown on the right. The door in the back leads through the maze to the LENS accelerator control area.

October 2004
Stacking of the TMR shielding commences. The TMR shielding consists of about 500 tightly-fitting blocks made from layers of lead and boron-impregnated polyethylene. The lead and boron reduce the flux of neutrons and gamma rays that are emitted from the TMR assembly.

November 2004 The final elements of the proton beamline are positioned. The blue components are dipole magnets used to steer the proton beam correctly onto the LENS neutron production target.

November 2004
Assembly of the TMR shielding continues. Almost all of the proton beamline magnets are installed and aligned.

December 2004
The final portion of the proton beamline and the reflector are installed. The beryllium neutron-production target is positioned within the reflector vessel. The reflector is filled with water are serves the purpose of “reflecting” stray neutrons back into the moderator. The moderator system is inserted into the rectangular cavity at the top of the reflector vessel. The shielding wall, half-stacked in the background, is to provide radiation isolation between the TMR vault and the proton accelerator vault.

December 2004
The completed accelerator system including the new ion source, foreground.

December 2004
The completed TMR assembly. The green circular layers on top are sheets of borated polyethylene. The PVC pipe on the left is the temporary neutron flight path leading to the SANS instrument.

December 2004
LENS graduate students Nick Remmes and Chris Lavelle make final adjustments to detectors on the SANS neutron flight path in preparation for the first neutron beam.

December 2004
40 mA of 25 keV protons passing through a vacuum chamber with an Argon background gas at a pressure of about 5 * 10**-5 Torr.

March 2005
Initial instrument setup at LENS. SANS installed in the foreground. This instrument is prototypes designed more for studying the source and commissioning detectors than for investigating materials due to the very low beam power (150W).

April 2005
Cryogenic moderator inserted into the Target Moderator Reflector Assembly.

April 2005
First cold neutron spectrum recorded from the LENS moderator. The simulation is from an MCNP calculation with the smeth22 kernel.

August 2005
First studies of neutron radiation effects in electronic cirtuits.

March 2006
First Emission time distribution measurement from the LENS moderator. MCNP simulation of the emission time distribution is shown as the blue line, the data points (for a 150 μsec proton pulse width) are shown in black. The long-time decay constant is set by the absorption characteristics of the LENS water reflector.

December 2006
Klystron RF power systems connected to the LENS accelerator for the first time. This is the first step in a major power upgrade that will take approximately 18 months to complete. It allowed peak currents up to 25mA (increased from 10mA), beam powers up to 1 kW (up from 150 W), and pulse rise-times as short a two microseconds.

December 2006
First klystron-powered proton beam delivered to a fluorescent screen.

January 2007
The Chemistry lab includes generous counter space, and standard instrument such as balances, pH meters, glassware etc.

February 2007
Reconfiguration of the first TMR vault for radiation effects research. Decommissioning of the prototype SANS and radiography instruments. The tape on the floor shows the future location of the main wall of the second TMR vault.

April 2007
Installation of main wall for second TMR vault. The vault will be finished with standard wall blocks, but this section is pour to eliminate any seams near the four penetrations for neutron instruments.

April 2007
Completion of the main wall for the second TMR vault. Penetrations for the four instrument beam lines are visible.

May 2007
Installation of the second TMR within the new vault. Shielding is also in place around the SANS beam line, and wall penetrations for two future instruments are visible on the left.

December 2007
Four shutters installed in the new TMR vault. Shielding between the beam lines is not yet completely installed. The first two sections of the evacuated SANS beamline are visible (one on top of the (closed) shutter).

December 2007
Original accelerator was moved back approximately 2.5 m in preparation for the installation of the second Drift Tube Linac (DTL). This second DTL will raise the proton beam energy from 7 MeV to 13 MeV, thereby increasing the neutron flux per unit proton current by a factor of roughly 4.

January 2008
Second high-voltage tank prepared for the installation of the third klystron which is needed to deliver power to the second DTL section to deliver 13 MeV protons.

January 2008
6 MeV DTL section installed in the LENS proton Beam Line. Beam (at 7MeV) was first successfully passed through this section of the accelerator on 24 January 2007. Energizing this section of the accelerator (to reach 13MeV) awaits completion of the installation of a third klystron.

February 2008
Final section of the primary flight path and the sample enclosure for the SANS instrument.