NEUP 2009 V1 - Revision history

Oborn: /* Proposed scope description and Scientific Merit (20%) */

2009-03-11T04:54:04Z

Proposed scope description and Scientific Merit (20%)

Oborn: /* Proposed scope description and Scientific Merit (20%) */

2009-03-11T04:47:08Z

Proposed scope description and Scientific Merit (20%)

Oborn: /* Proposed scope description and Scientific Merit (20%) */

2009-03-11T04:37:11Z

Proposed scope description and Scientific Merit (20%)

Oborn: /* Work Scope Challenges and expected innovations */

2009-03-10T23:58:14Z

Work Scope Challenges and expected innovations

Oborn: /* Quality Assurance */

2009-03-10T23:58:03Z

Quality Assurance

Oborn: /* Roles of Participants and Team Qualifications (15% or 2 pages) */

2009-03-10T23:57:43Z

Roles of Participants and Team Qualifications (15% or 2 pages)

Oborn at 23:57, 10 March 2009

2009-03-10T23:57:07Z

Show changes

Oborn: New page: Photofission of Actinides with Linearly Polarized Photons A PDF version of the RFP is given below Media:NEUP_RFP_2008.pdf ;Proposal Due date: 11:59 am March 16,2009 ;3/4/09: prepr...

2009-03-10T23:52:39Z

New page: Photofission of Actinides with Linearly Polarized Photons A PDF version of the RFP is given below Media:NEUP_RFP_2008.pdf ;Proposal Due date: 11:59 am March 16,2009 ;3/4/09: prepr...

New page

Photofission of Actinides with Linearly Polarized Photons

A PDF version of the RFP is given below

[[Media:NEUP_RFP_2008.pdf]]

;Proposal Due date: 11:59 am March 16,2009

;3/4/09: preproposal + Budget to dave harris
; 3/10/09 : first draft
;3/13/09: final version (of course not Dan's working the weekend)

10 page narrative

==Guidelines==

[[Media:NEUP_Capabilities.pdf]]

[[Media:NEUP_Man.pdf]]

[[Media:NEUP_narrb.pdf]]

[[Media:NEUP_pricing.pdf]]

[[Media:NEUP_TE.pdf]]

[[Media:NEUP_Teaming.pdf]]

=Go/NoGo requirements=

#Commitment to reporting
#If DOE Lab Work and safety Health program
#Export Control
#Standard Research Subcontract
#Quality Assurance if non-academic partner
#commitment to prepare additional contracts

=Proposal Outline=
Title:
\begin{center}
{\bf \Large Photofission of Actinides with Linearly Polarized Photons}\\
Technical Workscope : AFS-2
\end{center}

==Technical Work Scope and Mission Relevance (20%)==
(D.Dale)

This project involves the investigation of nuclear photofission at a fundamental level. Its primary goals are to

(1) ascertain
if the angular distribution of fission fragments from active interrogation of linearly polarized photons will result in a signature
in the form of easily detected neutron asymmetries, and if so,

some reviewers in the past have misinterpreted proposals thinking they were
going to detect the fission fragments. We should reduce this risk as
much as possible. How about the following sentence to replace the one above

measure the asymmetric neutron emission resulting from anisotropic fission
fragment emission when actinides are actively interrogation using linearly polarized photons

(2) evaluate the potential for utilization of this phenomenon in the areas of materials control and accountability
and as a technique to quantify actinides for safeguards and quality control applications. The method for the production of linearly polarized
photons from a bremsstrahlung beam described in this proposal is well established and can be readily implemented as an add on to other
systems using bremsstrahlung beams for active interrogation.

Change
The fundamental measurements of the dependencies of the fission fragment angular distributions
and their expected manifestation in the neutron angular distributions, however,
constitute a new, previously unexplored area of investigation.

To

The fundamental measurements of the neutron angular distributions, a result of the
fission fragment angular distributions,
constitutes a new, previously unexplored area of investigation.

==Proposed scope description and Scientific Merit (20%)==
(D.Dale)

For linearly polarized photons and considering only electric dipole (E1) transitions,
the photofission of an even-even
nucleus ($J^{\pi} = 0^+$, such as $^{238}U$) gives the
angular distribution of the fission
fragments \cite{Geissen1982}:

\begin{equation}

<math>
W(\theta,\phi) = A_o + A_2 (P_2(cos \theta) + P_{\gamma} f_2(1,1)
cos 2\phi P2_2(cos \theta))
</math>

\end{equation}

The angular distribution coefficients $A_o$ and $A_2$ depend on the
transition
state (J,K), where <math>K</math> is the projection of the total spin $J$ on the
symmetry axis of the deformed nucleus. For $J = 1, K = 0$, we have
$A_o = 1/2, A_2 = -1/2$ and for $J = 1, K = 1$, we have $A_o = 1/2, A_2 =
1/4$.
$P_2 = \frac{1}{2}(2 - 3 sin2 \theta)$, $P_{\gamma}$ is the
photon polarization, and $f_2(1,1) = 3 sin2 \theta$. $\theta$ is the
polar
angle with respect to the beam and $\phi$ is the azimuthal angle ($\phi =
0$
parallel to the electric field vector and $\phi = \pi/2$ perpendicular to
E). \\

For any target thicker than a few $mg/cm2$, of course, the fission
fragments
are not detectable. The question we wish to address here concerns whether
or
not the angular asymmetry in the fission fragments is manifest in the
angular
distribution of the prompt neutrons which they emit, thus providing a
possible signature for the presence of photofission.
\\

To a very good approximation, the
recoiling
fission fragments emit neutrons isotropically in their center of mass\cite{Ploeg95}.
A fully accelerated fission fragment travels with a speed of about 4\% of
the speed of light. In the center of mass of the fragment, a typical
1 MeV neutron travels with a $\beta$ of about $4.6$\% of $c$.
Thus, the neutron
energy spectrum measured in the laboratory is a convolution of the
"primordial" spectrum which the excited fission fragment emits, and the
kinematical effects due to the fragment recoil.
\\

These effects were examined under the following assumptions:

\begin{itemize}

\item{}The fission fragment mass distribution was sampled uniformly
between
$85<A<105$ and $130<A<150$.

\item{}A fixed amount of total kinetic energy, 175 MeV,
is given to the two fission
fragments.

\item{}Neutrons are emitted isotropically in the center of mass of the
fully accelerated fission fragments with an energy distribution given by:

\begin{equation}
N(E) = \sqrt{E} exp(-E/0.75)
\end{equation}

This reproduces the fission laboratory neutron energy distribution as
measured
with $(n,f)$.

\item{}The fission fragment angular distribution is sampled in both
$\theta$ and $\phi$ as noted above
for either K = 0 or K = 1, and the neutrons were given the appropriate
kinematic boost.

\item{}The resulting rate asymmetry
$\frac{N(\theta = \pi/2 ,\phi = 0)}{N(\theta = \pi/2,\phi = \pi/2)}$
is calculated for $P_{\gamma} = 0.3$. This degree of polarization
is commensurate with that attainable by using off axis bremsstrahlung,
as described below.

For a pure $K = 0$ transition, the resulting $\phi$ distribution is shown
in
the figure~\ref{fig:k0k1}. The resulting rate asymmetry,
$\frac{N(\theta = \pi/2,\phi = 0)}{N(\theta = \pi/2,\phi = \pi/2)}$ is
1.25, reflecting
the angular distribution of the fission fragments as well as the
"washing out" effect of the neutrons emitted isotropically in the frame
of the fission fragment. This asymmetry is for the case in which there is
no cut on the neutron energy. If one imposes the cut $E_n > 2$ MeV in the
simulation,
the asymmetry rises to 1.37. For the pure $K = 1$ case, the resulting
$\phi$ distribution is also shown in
figure~\ref{fig:k0k1}.
The corresponding rate asymmetry in this case is 0.84
without any neutron energy cut.

\begin{figure}
\vspace*{-0.5in}
\begin{center}
\begin{minipage}[t]{0.58\linewidth}
\epsfig{file=k0k1.eps,width=\linewidth}
\end{minipage}\hfill
\begin{minipage}[t]{0.38\linewidth}
\vspace*{-5cm}\caption{Monte Carlo $\phi$ distribution of neutrons at
$\theta = 90^{\circ}$. Solid: $K = 0$. Dashed: $K= 1$.}
\label{fig:k0k1}
\end{minipage}
\end{center}
\end{figure}

[[Image:k0k1.jpg|thumb|k0k1]]

These asymmetries are merely representative of what one {\em might}
observe. In the measurements proposed here, fission in actinides will be
induced by a bremsstrahlung beam of continuous energy. In practice,
fission
may proceed via multiple channels, and one cannot directly calculate the
expected neutron asymmetries. As such, we propose a complete experimental
investigation
of the $\theta$ and $\phi$ distributions of the neutron yields for a
number
of actinides to ascertain the magnitude of the asymmetries and to
determine
the sensitivity of the technique.
\\

{\bf Proposed production of linearly polarized photons
at the IAC}\\

As described in the {\em Facilities} section of this proposal, the experimenters have
ready access to a number of low energy (10's of MeV) electron linacs.
We propose to construct a beamline for the production of linearly
polarized
bremsstrahlung
photons modeled after that constructed by the Geissen group.
It is well known that when an electron beam strikes a thin radiator, the
resulting bremsstrahlung radiation which lies off axis from the
incident beam is
polarized as shown in figure \ref{fig:offaxisc}. If one collimates the
photon beam
at an angle of $\theta = \frac{m_e}{Ee}$ where $m_e$ is the rest mass of
the electron and $E_e$ is the energy of the incident beam, the
polarization
is maximized. A schematic of the relevant geometry is shown
in the figure. The energy dependence of the polarization of such a beam,
as measured by a
polarimeter which is based on the large analyzing power of the
photodisintegration
of the deuteron, is shown in figure \ref{fig:pol} where it can be seen
that modest
polarizations of the bremsstrahlung beam can be obtained. The rate of the
photons as compared to the uncollimated case
is decreased by approximately a factor of 20 to 30 due to the
collimation
as well as the need for a thin radiator to minimize multiple scattering
of the incident electrons.

\begin{figure}[ht]
\centering
\psfig{figure=offaxisc.eps,height=5.in,width=7.in}
\caption{Production of linearly polarized bremsstrahlung photons by the off axis technique.}
\label{fig:offaxisc}
\end{figure}

[[Image:offaxisc.jpg|thumb|offaxisc]]

\begin{figure}[ht]
\centering
\psfig{figure=pol.eps,height=5.in,width=7.in}
\caption{Polarization as a function of photon energy for the off axis
bremsstrahlung production of linearly polarized photons. Figure is from
\cite{Geissen1987}.}
\label{fig:pol}
\end{figure}

We propose to
construct such a linearly polarized bremsstrahlung beamline and a
polarimeter
to measure its performance.
This facility will be used to measure the angular dependence of
the photofission
neutron yields as a function of both the bremsstrahlung endpoint
energy and the neutron energy
to evaluate the sensitivity of this technique to the
presence of photofission events. A schematic of the proposed experimental setup is shown in figure \ref{fig:hrrl}.
It consists of a pulsed electron accelerator delivering approximately 14 MeV electrons which are bent 90 degress in the horizontal plane.
The electrons are then bent up or down in the vertical plane approximately two degrees before they strike a thin bremsstrahlung converter.
A fixed collimator is placed downstream of the bremmstrahlung radiator and is offset in the horizontal plane. This collimator passes bremstrahlung photons which are off axis from
the primary electron beam, and therefore are linearly polarized 45 degrees with respect to the horizontal, with an orientation depending upon the angle of incidence of the electron beam on the bremsstrahlung radiator. Between the radiator and the collimator, a magnet deflects charged particles in the horizontal plane
away from the photon collimator. The photons exit the vacuum via a thin window at the downstream edge of the collimator. This window serves a a thin converter for a pair
spectrometer luminosity monitor which is used for relative normalization of flux in the two polarization states. In addition to the converter, the pair spectrometer consists of
a 0.35 T, 20 cm dipole magnet and two plastic scintillator detectors to measure the electrons and positrons in coincidence. Downstream of the pair spectrometer will be the target. When polarimetry experiments are being performed, this target will consist of $D_2O$ and during production runs will generally be a solid actinide target. A plastic scintillator neutron detector will be placed at an angle of 90 degrees with respect to the beam, at a 45 degree angle from the horizontal plane. This detector will measure the neutron yields as a function of the orientation of the polarization. A second detector will be placed at a 90 degree angle with respect to the beam in the horizontal plane. The purpose of this detector will be to monitor the setup for false asymmetries.

\begin{figure}[ht]
\centering
\psfig{figure=Hrrl_valeriia_1.eps,height=5.in,width=7.in}
\caption{A schematic of the proposed experimental setup.}
\label{fig:hrrl}
\end{figure}

[[Image:hrrl-1.jpg|thumb|hrrl]]

Neutrons will be identified via the time of flight method, with the start signal coming from the accelerator beam pulse.
In October 2008, a test run was performed with a deuterated water
target and the results are shown in figure \ref{fig:tony}, where the neutron time of flight peak can be clearly distinguished from the
photon flash. Furthermore, the neutron peak is greatly reduced when the target is $H_2O$.

\begin{figure}[ht]
\centering
\psfig{figure=tony.eps,height=5.in,width=7.in}
\caption{Neutron time of flight spectra for $D_2O$ and $H_2O$ targets.}
\label{fig:tony}
\end{figure}

[[Image:tony.gif|thumb|tony]]

==Bibliography==

\section{Bibliography}

\begin{thebibliography}{99}

\bibitem{Geissen1982}R. Ratzek, {\em et al.} Z. Phys. A -- Atoms and
Nuclei 308, 63-71 (1982).

\bibitem{Geissen1987}U.E.P. Berg and Ulrich Kneissl, Ann. Rev. Nucl. Part.
Sci. 37, 33-69 (1987).

\bibitem{Ploeg95}H. van der Ploeg {\em et al.}, Phys. Rev. C, 52, no. 4 (1995).

\bibitem{gpnp}M.P. De Pascale, {\em et al.}, Phys. Rev. C, 32, no. 6 (1985).

\end{thebibliography}
(D.Dale)

==Milestones==

12 months: Acquire and assemble instrumentation-(vacuum pipe for electron
beam dump, beam dump magnet, exit window/pair converter, radiator, four PMTs + bases, octal
discriminators, 4-fold logic unit)

24 months: commission experimental setup, begin measurements

36 months: report on measurements with application assessment

==Timeline and Deliverables==

The proposed work plan for this project is as follows:

\begin{itemize}

\item{} month 6: Develop beam diagnostics including two view screens for monitoring the position and angle of the electron beam, and a pair spectrometer photon flux monitor consisting of a converter target, dipole magnet, and plastic scintillation detector.

\item{} month 12: Establish beamline for linearly polarized photons. This will consist of the installation of a new vacuum system, a remotely removeable bremsstrahlung radiator, coil deflector magnets to deflect the beam up and down two degrees to vary the photon beam polarization, and an off axis photon beam collimator.\\

\item{}month 20: Verify the production of linearly polarized beam using the high
analyzing power of the photodisintegration of the deuteron. Here, we will measure the azimuthal dependence of the neutron yields from deuterated water targets. Backgrounds will be directly measured using and identical setup except with an $H_2O$ target.

\item{}month 24: Measure neutron azimuthal asymmetries for actinides as a function of target, bremsstrahlung endpoint energy, and neutron energy.

\item{}month 30: Measure neutron azimuthal asymmetries for a variety of other targets to investigate the possibility of false positives.

\item{}month 34: Assemble an overall assessment of the effectiveness of the technique for safeguards applications.

\item{}month 36: Publish the results.

\end{itemize}

==R&D resources and Capabilities (10%)==
[[Image:hrrl.jpg|thumb|The High Rep Rate Linac (HRRL).]]

[[Image:countroom.jpg|thumb|HRRL counting room. Signal processing electronics and the MPA data acquisition system are shown.]]

The research and development resources to support this proposal include an in house electron accelerator, several particle detector systems, and signal processing electronics.
The linac shown in Figure~\ref{fig:hrrl) is capable of accelerating electrons up to energies of 16 MeV. The electrons are transported in pulse trains having a minimum width of 25 ns and a maximum repetition rate of 1 kHz. The accelerator can produce 80 mA peak currents which can intersect a radiator target to produce bremsstrahlung photons. The bremsstrahlung photons enter an experimental cell through a collimator configured to select off axis polarized photons. A target, in the experimental cell, is positioned in the path of the polarized photons.

Particle detection systems are placed at predetermined locations in the experimental cell to measure the reactants emanating from the target. The authors of this proposal performed a previous photofission experiment using two neutron sensitive scintillators place at 90 degrees to the incident photon beam and in the same plane as a 20 cm long target of heavy water (D2O). A NaI crystal optically coupled to a photomultiplier tube (PMT) was placed off the beam line axis at the end of the experimental cell to monitor the incident photon flux. The photomultiplier signals were amplified by Ortec Model 672 amplifiers and discriminated using a CAEN constant fraction discrimiator model N842. The NaI detector output was sent directly to a sampling ADC manufactured by FAST~\cite{FAST7070ADC} while the neutron detector outputs were send to a time to amplitude converter (ORTEC 567, 566). The TAC output is proportional to the neutron time of flight and was measured with the ADCs manufactured by FAST~\cite{FAST7070ADC}. A data acquisition system based on MPA-3 ~\cite{MPA-3} recorded the measurements for analysis. Figure~\ref{fig:n_ToF} shows a sample Time of Flight (ToF) spectrum from the neutron sensitive detectors. The spectrum illustrates the apparatus' ability to identify particles with flight times consistent with photons and distinguish them from particles with flight times consistent with neutrons.

\bibitem{MPA-3} Fast ComTec GmbH, Grunwalder Weg 28a, D-82041 Oberhaching Germany

\bibitem{FAST7070ADC} http://www.fastcomtec.com/products/product-lines/nim-modules/7070.html

\bibitem{ORTEC567TAC}http://www.ortec-online.com/electronics/tac/567.htm

\bibitem{ORTEC672Amp}http://www.ortec-online.com/electronics/amp/672.htm

\begin{figure}[ht]
\centering
\psfig{figure=hrrl.eps,height=5.in,width=7.in}
\caption{}
\label{fig:hrrl}
\end{figure}

\begin{figure}[ht]
\centering
\psfig{figure=countroom.eps,height=5.in,width=7.in}
\caption{}
\label{fig:countroom}
\end{figure}

(V.S.- pictures + T.Forest - description)

CUT ALL THIS, NO? (DD)
Yes! or Move (TF)

Idaho State University and the Idaho Accelerator Center have a number of electron linacs capable of generating
milliamp beams of electrons with energies up to 40 MeV.
Our proposed beamline for the production of linearly
polarized
bremsstrahlung
photons will be modeled after that of the Geissen group\cite{Geissen87}.
We propose to
construct such a linearly polarized bremsstrahlung beamline and a
polarimeter
to measure its performance,
and to measure the angular dependence of
the photofission
neutron yields as a function of both the bremsstrahlung endpoint
energy and the neutron energy (as determined by time of flight)
to evaluate the sensitivity of this technique to the
presence of photofission events.

==Roles of Participants and Team Qualifications (15% or 2 pages)==

Participant A = D.Dale = Manager Photofission physics

Participant B = V. Starovoitova = Data analysis expert

Participant C = T. Forest = DAQ, beam line design

Participant D = P. Cole = beamline instrumentation, expert complainer

Students = 2 PhD theses + 2 MS theses, 2 undergrad training

==Work Scope Challenges and expected innovations==

(B.S)

==Quality Assurance==
The procedures used to carry out this research and the results obtained will be documented in refereed journals. In addition, full documentation will be
recorded in graduate student theses and dissertations.
Laboratory notebooks will be maintained throughout the project and will be available for inspection by the funding agency at any time.

:10 pages

=Budget form=
Materials and supplies: 26k

4 PMT - 5k
beam pipe - 15k
collimator - 5k
scintillators - 1k

= Proposal Graphs=

[[Image:ToF_H20r199_D20r229.gif| thumb| The time of flight measured by detector A. The unhatched histogram represents the flight time observed when a D2O target is used while the hatched histogram is observed when using the H2O target]]

[[Image:asym.jpg|thumb|asym]]

[[Image:pol.jpg|thumb|pol]]

[[Image:hrrl-val1.jpg|400px]]

[[Image:hrrl-val2.jpg|400px]]

[[Image:hrrl-val3.jpg|400px]]

@@ Line 427: / Line 427: @@
 Participant C - Data acquisition manager\\
-Participant C has a breadth of experience in high precision asymmetry measurements, data acquisition systems, elementary particle detectors, and beam line instrumentation.  For over 10 years, participant C has performed and published experiments measuring asymmetries similar to those proposed here.  Participant C has a similar level of experience setting up data acquisition systems used by nuclear physics experiments.
+Participant C has a breadth of experience in high precision asymmetry measurements, data acquisition systems, and elementary particle detectors.  For over 10 years, participant C has performed and published experiments measuring asymmetries similar to those proposed here.  Participant C has a similar level of experience setting up data acquisition systems used by nuclear physics experiments.  The above experiences will provide a strong foundation to execute the work within this proposal.
 Participant D - Beam line instrumentation\\

@@ Line 425: / Line 425: @@
 Participant B - Data analysis coordinator\\
-Participant C - Data acquisition manager, beam line design\\
+Participant C - Data acquisition manager\\
-Participant C has a breadth of experience in high precision asymmetry measurements, data acquisition systems, elementary particle detectors, and beam line instrumentation.  For over 10 years, participant C has been performed and published experiments to measure asymmetries similar to those proposed here.  Participant C has a program of detector development
+Participant C has a breadth of experience in high precision asymmetry measurements, data acquisition systems, elementary particle detectors, and beam line instrumentation.  For over 10 years, participant C has performed and published experiments measuring asymmetries similar to those proposed here.  Participant C has a similar level of experience setting up data acquisition systems used by nuclear physics experiments.
 Participant D - Beam line instrumentation\\

← Older revision		Revision as of 04:37, 11 March 2009
Line 426:		Line 426:

	Participant C - Data acquisition manager, beam line design\\		Participant C - Data acquisition manager, beam line design\\
		+
		+	Participant C has a breadth of experience in high precision asymmetry measurements, data acquisition systems, elementary particle detectors, and beam line instrumentation. For over 10 years, participant C has been performed and published experiments to measure asymmetries similar to those proposed here. Participant C has a program of detector development

	Participant D - Beam line instrumentation\\		Participant D - Beam line instrumentation\\

← Older revision		Revision as of 23:58, 10 March 2009
Line 573:		Line 573:


−
−	~~==Work Scope Challenges and expected innovations==~~
−
−	~~(B.S)~~

← Older revision		Revision as of 23:58, 10 March 2009
Line 578:		Line 578:
	(B.S)		(B.S)

−	~~==Quality Assurance==~~
−	~~The procedures used to carry out this research and the results obtained will be documented in refereed journals. In addition, full documentation will be~~
−	~~recorded in graduate student theses and dissertations.~~
−	~~Laboratory notebooks will be maintained throughout the project and will be available for inspection by the funding agency at any time.~~

−
−
−	~~:10 pages~~

	=Budget form=		=Budget form=

← Older revision		Revision as of 23:57, 10 March 2009
Line 572:		Line 572:
	presence of photofission events.		presence of photofission events.

−	~~==Roles of Participants and Team Qualifications (15% or 2 pages)==~~

−
−	~~Participant A = D.Dale = Manager Photofission physics~~
−
−	~~Participant B = V. Starovoitova = Data analysis expert~~
−
−	~~Participant C = T. Forest = DAQ, beam line design~~
−
−	~~Participant D = P. Cole = beamline instrumentation, expert complainer~~
−
−
−	~~Students = 2 PhD theses + 2 MS theses, 2 undergrad training~~

	==Work Scope Challenges and expected innovations==		==Work Scope Challenges and expected innovations==