# Addendum to the SY 120 Shielding Assessment

# to add the MCenter branch to the beam line

![](media/image1.wmf){width="6.242361111111111in"
height="3.973611111111111in"}

## C. Brown, D. Jensen, October 6, 2003

# 

# Addendum to the SY 120 Shielding Assessment to include the MCenter branch of the beam line in the Meson Laboratory

## **1. Introduction**

The MCenter beam line shown schematically on the cover of this document
serves to provide a secondary beam of π^±^,K^±^, and p^±^ particles to
the MIPP(FNAL-E907) experiment located in the MC7 area of the Meson Lab.
The secondary beam momenta will range from 5GeV/c to 90GeV/c. This is
known as the 'pion' mode of operation. Later on, the secondary beam line
will be reconfigured to transport a low intensity beam of 120GeV/c
protons to interact with the MINOS target. This mode of operation, known
as the 'proton' mode will occur later in the experiment and a separate
shielding assessment will be filed at the appropriate time.

The documents being presented examine the shielding in the secondary
beam line located in M05 and MC6 areas as well as the experimental hall
in MC7. The MCenter primary 120 GeV proton beam line starts in the M01
enclosure, proceeds through the M02, M03, M04, and M05 enclosures, and
is targeted and absorbed at the upstream end of the MC6 enclosure. The
MCenter primary beam line is a very simple proton beam transport that
contains only two dipole bends (in M01 and M05) and only two quad
doublets (in M02 and M05). The intensity of the beam can be reduced to
the low intensities requested by the E907 group by adjusting the Meson
Lab triple split in enclosure F1 to direct excess beam to the Meson
Target Train Beam Absorber. [Appendix
MC-1](http://ppd.fnal.gov/experiments/e907/Beam/mipp_primary_beam_sheet.htm),
the MCenter beam sheet, lists all the components in longitudinal order.

The 120 GeV primary beam creates a secondary beam of hadrons, the 'pion
beam', which is transported by a short secondary beam line in MC6 to the
E907 experiment in enclosure MC7. [Appendix
MC-7](http://ppd.fnal.gov/experiments/e907/Beam/mipp_beam_sheet_8.htm),
the MCenter secondary beam sheet, lists all the components of the
secondary beam line up to the E907 target in longitudinal order. This
shielding assessment addresses the primary beam line from M01 to MC6 in
Section 2 below, the secondary beam line in MC6 in Section 3 below, and
the E907 experimental area in MC7, in Section 4 below.

**2.** **MCenter Primary Proton Beam Line, M01 -- MC6**

The primary beam line is evaluated for an intensity of 2e12 120 GeV
protons per 2.9 second Main Injector cycle. [Appendix
MC-2](http://home.fnal.gov/~chuckb/MC02.xls) lists the shielding
requirements for this intensity as determined by the Cossairt
requirements and the Fermilab Radiological Standards.

The longitudinal and transverse shielding was examined and the results
are displayed in the shielding spreadsheets in [Appendix
MC-3](http://home.fnal.gov/~chuckb/MC03.xls) and [Appendix
MC-4](http://home.fnal.gov/~chuckb/MC04.xls). The shielding is
sufficient to protect against a continuous loss of 2e12 120 GeV protons
per 2.9 second Main Injector cycle or a single pulse accident of 3e13
120 GeV protons at all points in the beam line up to and including the
momentum collimator in MC6. The shielding is sufficient to protect
against a continuous loss of 2e5 90 GeV (or less) hadrons in the
secondary beam beyond the momentum collimator in enclosure MC6 and in
enclosure MC7 (or a single pulse accident of 4e6 hadrons in these
secondary beam regions), see below.

For Experiment E907, the first user of this beam, the proton beam will
be targeted on a 20 cm long copper target in MC6. Jim Kilmer has
designed this target to withstand a continuous beam intensity of 2e12
every 2.9 seconds. A MARS simulation of the target location shielding in
MC6 was made. The results are found in [Appendix
MC-5](http://waldo.fnal.gov/~kostin/SAS/sas.pdf) and are based on an
integrated intensity of 2e16 protons per year, twice the maximum
integrated beam that E907 intends to record. The groundwater limits are
not exceeded.

The labyrinths and penetrations into the MCenter beam line are examined
in [Appendix MC-6](http://home.fnal.gov/~chuckb/MC06.xls). The shielding
around the labyrinths and penetrations is sufficient for an intensity of
2e12 120 GeV protons per 2.9 second Main Injector cycle. The two
penetrations in MC6 which would otherwise fail penetrate through to the
MWest/M05 primary beam enclosure which is interlocked whenever the
MCenter beam is enabled.

Air activation is adequately covered in the 'Air Activation' section of
the main SY120 SA. Note that the M05 and MC6 enclosure ventilation is
configured to ensure that any air activation from the MC6 target and
beam absorbers is carried upstream through M05 before being vented into
a fenced radiation area above the M05 enclosure.

Muon production from the M01 beam absorber is covered in the SY120 SA.
Muon production from the beam absorber in the MC6 enclosure has been
modeled using MARS; see the discussion of the MC7 E907 experimental area
muon rates in section 4 below.

The only major residual radiation problems will occur at the M01 beam
absorber, the MC6 copper target, the first few MC6 magnets, and the MC6
beam absorbers. The residual rates expected for the E907 running are
shown in [Appendix
MC-5](http://ppd.fnal.gov/experiments/e907/Beam/sas.pdf). These can
easily be controlled using standard Beams Division operating procedures.

Three integrating radiation detectors located on the roof of the
shielding pile in MC6 (the area with the least shielding) are used to
protect against the inadvertent transport of more than 2e12 120 GeV
protons per pulse to MC6 (or more than a single one-pulse accident of
3e13 protons).

The integrated beam transmitted down the MCenter beam line will be
monitored by the Beam Budget Monitor recording the incident proton
intensity on the MC6IC ion chamber.

Conclusion: the shielding of the MCenter 120 GeV primary proton beam
line from enclosure M01 to MC6 in the Meson Lab is adequate to protect
against the accidental loss of 2e12 120 GeV protons per 2.9 second Main
Injector acceleration cycle.

**3. MCenter Secondary Hadron Beam Line in MC6**

A short secondary beam line has been constructed in the MC6 enclosure.
The elements of this beam line are listed in the beam sheet, [Appendix
MC-7](http://ppd.fnal.gov/experiments/e907/Beam/mipp_beam_sheet_8.htm).
The beam line elements are shown in

Figure 1. Figure 2 shows a cut view of the beam line and Figure 3 shows
the beam optics.

![](media/image2.wmf){width="3.2416666666666667in"
height="3.7583333333333333in"}

Figure 1 MIPP secondary beam line elements

![](media/image3.wmf){width="3.2416666666666667in"
height="3.7583333333333333in"}

Figure 2 Side view of MIPP secondary beamline

![](media/image4.wmf)

Figure 3 Beta functions in the horizontal (x) and vertical (y)
directions for the beam line. The beam is brought to a focus in both
planes at the momentum selection collimator placed at 33m downstream of
the primary target (0m). The beam is focused again at the secondary
(experiment) target at 95.95m. The vertical dispersion is designed to be
large at the collimator and the beam is designed to have low divergence
at the beam cerenkov counters.

The E907 experiment has requested a number of different secondary hadron
beam conditions. They are detailed in [Appendix
MC-8](http://ppd.fnal.gov/experiments/e907/Beam/MIPP beam needs.pdf). To
summarize, they wish to take a total of about 1e16 120 GeV protons onto
their primary beam target in MC6 with an average intensity of about 1e10
protons per spill.

Note, the run condition table specified by the E907 experimenters in
[Appendix
MC-8](http://ppd.fnal.gov/experiments/e907/Beam/MIPP beam needs.pdf)
includes 'proton mode' runs wherein they wish to transport 125,000 120
GeV protons/pulse, without a primary target in MC6, directly to their
secondary target in MC7. The 'proton mode' running will not occur until
at least one year after data taking has begun for E907. The experience
obtained running the MC6 section of the beam in a secondary 'pion' beam
configuration will be invaluable in determining the safest configuration
for the primary beam 'proton mode'. Therefore this assessment explicitly
DOES NOT include running the MC6 beam line in the 120 GeV primary beam
'proton mode'.

In the secondary 'pion beam' mode, the primary beam is targeted at the
upstream end of the MC6 enclosure and a secondary pion beam of energies
from +90 to --90 GeV will be transported through MC6 to the E907
experiment in MC7. This is the mode that this shielding assessment will
address. For one of the 'pion mode' conditions, namely --90 GeV negative
pions, they will request a primary beam intensity of 2e11 protons/pulse.
This is because the K^-^ and antiproton yields are lowest at -90GeV/c
and a larger primary proton intensity is required to get adequate fluxes
of these minority particles in the secondary beam. Despite this lower
maximum intensity request, we have installed interlocks, and have
shielded the area, to address an intensity of 2e12 per pulse. The
secondary intensity in MC7 will be limited by radiation detectors (in
MC7) to 2e5 hadrons per pulse, the maximum intensity that the E907
detector can withstand, see below.

In 'pion mode' the secondary beam line in MC6 will be limited to an
energy setting of 90 GeV or below with an interlocked current upper
limit on the MC6D1 EPB dipole string. The momentum collimator in MC6,
MC6CY, has been physically modified to limit its maximum vertical
opening to 1.0 inch, i.e. --0.5 to +0.5 inches. When the MC6D1 current
string is set to transport 90 GeV secondary particles, 120 GeV
uninteracted protons from the primary beam hit the collimator at least
1.0 inches above the center of the momentum collimator. The tight
collimation just downstream of the primary target combined with the fact
that the four dipoles in the MC6D string are all in series make it
impossible to mis-steer the primary beam through the collimator opening.
MARS simulations have shown that there are no uninteracted particles
(for a MARS run with 100,000 primary protons) that traverse the MC6 beam
line into MC7. At other 'pion mode' settings, the uninteracted protons
are intercepted either higher on the momentum collimator or on elements
of the beam line upstream of the momentum collimator. For a schematic
view of the trajectories of the uninteracted primary 120 GeV protons see
[Appendix MC-5](http://waldo.fnal.gov/~kostin/SAS/sas.pdf).

In 'pion mode' the maximum intensity of primary protons (plus secondary
hadrons) will be limited in MC6 by radiation detectors to less than
2e12. The maximum intensity transmitted by the secondary beam line
through to MC7 will be limited to the equivalent of 200,000 120 GeV
protons/pulse by radiation detectors. A single pulse accident of 3e13
protons per pulse (20 times more intensity) from the Main Injector is
not a problem since the maximum 2.9 sec. pulse rate assumed (1200 pulses
per hour) means the D.C. rate dominates the shielding calculations.

The shielding of the MCenter secondary beam line in enclosure MC6 is
configured to handle primary proton beam intensities up to 2e12 120 GeV
protons every 2.9 seconds from the primary target location to the
momentum collimator location. This is necessary since the uninteracted
primary beam interacts at different places in MC6 depending on the
energy setting of the secondary beam line. [Appendix
MC-5](http://waldo.fnal.gov/~kostin/SAS/sas.pdf) includes a schematic of
the region of the secondary beam where the uninteracted 120 GeV primary
protons are absorbed by the magnetic elements and the absorbers. MARS
calculations show that the radiation fields expected outside the MC6
enclosure are greatest on the roof of the enclosure and hence that is
where the radiation detectors are placed to limit the beam intensity,
see [Appendix MC-5](http://waldo.fnal.gov/~kostin/SAS/sas.pdf).
[Appendix MC-3](http://home.fnal.gov/~chuckb/MC03.xls) and [Appendix
MC-4](http://home.fnal.gov/~chuckb/MC04.xls) also show that the
longitudinal and transverse shielding in these regions meets the
Cossairt criteria.

The only labyrinth into the MC6 shielding in the Meson Detector Building
is the entrance gate on the west side of the shielding pile as listed in
[Appendix MC-6](http://home.fnal.gov/~chuckb/MC06.xls).

Air activation issues in MC6 are addressed in section 2 above.

Ground Water and Muon production from the primary beam in MC6 is
addressed in section 2 above.

The only active shielding controls are the three Radiation Detectors
located on the roof of the MC6 enclosure. These detectors will monitor
the DC dose rates in the MC6 enclosure and will be adjusted to limit the
hadron flux to 2e12 per 2.9 seconds.

Thus the MC6 secondary beam line can be safely operated with incident
proton intensities up to 2e12 protons per 2.9 seconds at secondary beam
energies of 90 GeV or below.

**4. MC7, the Secondary Hadron Beam Enclosure and E907 Experiment**

MIPP (E907) Experimental Hall Shielding Assessment - D. A. Jensen

This document addresses the radiation shielding needs for MC7 and the
portacamps for the MIPP experiment (E907). The area to be addressed is
MC7 (where the experiment is located); the portacamps adjacent to MC8
where the experimenters will work during shifts, and the secondary beam
stop just downstream of MC7. The muon plumes extending downstream of
this area will be addressed. The running conditions addressed are those
for secondary running. The layout of the beam lines and experiment are
detailed in drawing 3907-500-ME-397560 below.

**The MIPP Experiment**

MIPP will run in the Meson Center beam line, using a maximum of 2x1011
120 GeV protons per spill to produce a secondary beam of charged π's and
K's. The π's and K's will impinge on a secondary target -- the
scattering on the secondary target being the focus of the experiment.
The secondary momenta will be ±5, ±10, ±15, ±25, ±50, ±70 and ±90 GeV/c.
The maximum intensity at which the experiment will run will be 1.25 x
10^5^ secondaries per one second spill (every 2.9 seconds or longer). In
this document, it will be assumed that the secondary beam will be
limited to intensities below 2.0 x 10^5^ secondaries per spill so as not
to overly constrain the experiment.

The secondary beam is absorbed entirely on the calorimeter at the
downstream end of the E907 spectrometer. The secondary beam is designed
to be less than 1 cm in diameter and to have a divergence of less than
0.5 mr. At the downstream end of the experiment, the divergence is
increased due to multiple scattering in the 0.14 radiation lengths of
material in the E907 spectrometer upstream of the calorimeter. At 5
GeV/c, the multiple scattering adds about 1 mr. to the beam divergence.
The beam size at the calorimeter thus grows to about 2 cm (rms). This
implies that at the low momentum setting, the secondary beam must hit
the calorimeters at least 5 cm from the edge (see discussion below).

The secondary beam flux is limited by the experiment; the detectors
cannot accept a higher flux. The primary beam shielding assessment is
dealt with above. The secondary beam intensity will be monitored using a
Chipmunk radiation monitor that will be placed near the upstream face of
the first Cerenkov counter immediately next to the secondary beam
entering MC7. This detector will be in the halo of both the secondary
beam and the detector elements in the beam at this location. It must be
calibrated and appropriate trip settings established as a part of the
initial commissioning of the beam. This protection will also serve to
protect against an accident condition of for example the full MI beam
being delivered to the MIPP primary target. That would be 4E13 as
opposed to the nominal of 2E12 or 20 times more beam. If the chipmunk
responds within 5 spills and the beam is then held off for one hour, the
fast pulse accident dose would not exceed the hourly limit.

The MIPP experiment layout is shown in Figure 4 below.

![](media/image5.wmf){width="4.6097222222222225in"
height="4.202083333333333in"}

Figure 4 Schematic of the MIPP apparatus. The beam Cerenkov counters are
not shown.

The experiment, situated in MC7, consists of a secondary beam line
containing beam transport pipes and a set of Cerenkov counters. The
target upon which the secondary beam impinges is located just inside the
JGG spectrometer magnet. Then follows a Cerenkov counter, a
time-of-flight scintillator wall and the ROSIE spectrometer magnet. Wire
chambers are interspersed among these elements. Downstream of ROSIE and
the wire chambers is a Ring Imaging Cerenkov Counter. Finally there is a
calorimeter -- the only massive (along the beam) device. The space from
the secondary target through the calorimeter is tightly packed with
apparatus.

There are two sources of radiation in MC7: the secondary beam, and muons
from the upstream primary and secondary beam lines. The methodology used
to analyze the radiation due to the hadron beam is outlined in section
4.1a below. Muons from upstream are tracked through the apparatus; the
track densities are then used to calculate dose rates in section 4.2a
below.

Dose Rates and Allowed Limits for Hadrons

The hadron-induced radiation may come from beam losses along the beam
line, from beam interacting in the apparatus, or from the secondary beam
dump. The methodology for dealing with beam losses and the beam dump are
discussed in section 4.1a below.

Dose due to the Secondary beam

Note that the absorption of the beam by the target and the resulting
reduction in secondary beam intensity is not included in this
discussion. These rates are 'target out' rates and are thus more
conservative.

The dose in the secondary beam line, using 25000 mip tracks/cm2 equals
one mrem, indicates that the dose in the beam (assuming a 1 sq cm beam)
is 5 mrem/spill or 5\*1200 = 6000 mr/hr. Clearly it is necessary that
access to the beam itself be excluded. Exclusion from the beam is
assured by having the experimental enclosure interlocked when beam is
enabled. It is also necessary that the secondary beam be dumped either
in the experimental hadron calorimeter or in the downstream beam dump
and is thus not allowed to exit the downstream end of the MC7 enclosure.

The worst case for a beam induced radiation accident is that of the
highest energy secondary beam hitting an 'optimal size steel log' that
someone has left inadvertently in the beam line. The radiation generated
is proportional to energy and flux, but for MIPP, the flux is held
constant at 125K particles per spill (as noted above, calculations here
assume 200 K particles per spill), so only the energy is variable. Since
the dose rate increases with increasing energy, if the highest energy
running (90 GeV/c) leads to acceptable radiation fields, the lower
energy running will also be acceptable. Using the methodology discussed
in section 4.1a below, the dose rate outside the MC7 building due to
total beam loss would be 0.6 mr/hr. This assumes 1200 spills per hour.
As this is well below the 100 mrem/hr allowed in a fenced area, no
constraints need to be added to the experimental layout.

Secondary Target

The secondary target is located inside the JGG. The yoke to the right
and left inside the JGG is 42 inch thick iron, more than adequate
transverse shielding.

Calorimeters

There are two calorimeters at the downstream end of the apparatus, an
electromagnetic calorimeter (EM) and a hadronic calorimeter. The length
of these objects is 0.35 and 9.7 interaction lengths respectively. The
transverse dimensions are 152.4 and 100 cm square respectively. The
hadron calorimeter will completely absorb the hadron component of the
secondary beam if the beam impinges inside the edges of the hadron
calorimeter. The methodology of section 4.1a below is used, noting that
for the EM calorimeter the material is Pb instead of Fe, so that the
interaction length is 1.47 times shorter.

There are two cases, radiation out the top and bottom, and radiation out
the sides. Consider first the case of radiation out the top or bottom.
Assume that the entire beam is absorbed in the hadron calorimeter.
Following the method of 4.1a below, the radiation out the top or bottom
of the calorimeter is less than 10 micro-rem/hour -- negligible on the
scale of the 100 mrem limit for a fenced area.

The case of radiation out the sides of the calorimeter is more complex
because the beam sweeps across the calorimeter system as a function of
secondary beam momentum. At 5 GeV/c, the secondary beam, about 47 cm off
axis, hits the EM calorimeter about 3 cm inside the Hadron Calorimeter.
This is far enough into the calorimeter that the beam is absorbed, but
not far enough into the calorimeter horizontally to provide any
self-shielding. This assumes that the spectrometer magnets are at their
nominal settings. If the spectrometer magnet currents are limited to
within ±10%, then in the worst case, the secondary beam of 5GeV/c misses
both calorimeters and a 10 GeV/c beam can hit about 12 cm inside the
edge of the Hadron Calorimeter. There is essentially no self-shielding
of the calorimeter and the dose rate outside the enclosure is about 0.14
mrem/hour for 125 K secondary beam ( 0.23 mrem/hr for 200 K secondary
beam). Again, this is not a problem for the fenced area. More seriously,
if the spectrometer magnets are set far from nominal -- for example if
the JGG is on but ROSIE is off -- the secondary beam misses not only the
calorimeter but also the beam dump. This is clearly unacceptable and is
prevented by interlocked limits on the two analysis magnet currents. An
analysis of where the beams of different momenta hit the calorimeter and
beam dump is given in [Appendix
MC-9](http://ppd.fnal.gov/experiments/e907/Beam/beam_dump.htm).

Beam Stop

There is a beam stop downstream of MC7. This is the beam stop installed
by E871, HyperCP. It is detailed in Drawing 9206.200-MD-328885. The beam
stop consists of a set of steel blocks 96 inches wide by 74 inches high
by 120.49 inches deep. The block is offset 18 inches beam left with
respect to the nominal beam line and is 117.25 inches above the nominal
floor level. (Beam height for MIPP is approximately 82 inches) If the
secondary beam is scattered by the EM calorimeter, this beam stop will
absorb the remaining secondary beam. If the beam is unscattered as it
hits the beam stop, there is the possibility of some of the secondary
beam penetrating cracks in the beam dump support and not being fully
absorbed. It is therefore required that the secondary beam impact the EM
calorimeter inside its edges by at least 5 cm. This requirement means
that the relative currents in the spectrometers be either both zero or
that the magnet set points are interlocked to be within 10% of nominal.

**Dose Rates and Allowed Limits for Muons**

The muon flux is assumed to come exclusively from upstream of MC7. This
muon flux has been calculated using MARS. The muons are tracked through
the experiment to the portacamps using the experiment Monte-Carlo
program. The results for muons in the portacamps are discussed in 4.1b
below. The muon fluxes are well below the limits imposed for continuous
occupancy.

The main muon fluxes are in plumes above and below the experiment. The
secondary beam is generated vertically from the primary beam and the
bending magnets associated with the control of the secondary beam
therefore bend vertically. These lobes are either into the
ground/Mbottom or are well above the height of the portacamps at that
distance from the experiment.

MIPP Experimental Hall Action Items

Install a Chipmunk near the upstream face of the first Cerenkov and the
secondary beam line in MC7. This Chipmunk will be calibrated during the
first engineering test runs of the beam line to trip the beam if the
secondary intensity exceeds 200 K particles/second.

The spectrometer magnets must have monitoring installed to assure that
the polarities are opposite and that the currents are nominal to within
+/- 10%.

With the current specifications and design of the spectrometer, the
secondary beam momentum must be constrained to be at or above 5 GeV/c.
This requirement is imposed because at lower momenta, the secondary beam
may be dumped near the edge of the hadron calorimeter in such a way that
the self-shielding is not adequate to keep dose rates outside the beam
enclosure below 0.05 mrem/hr. It would be possible to remove this
constraint with a modest adjustment of the spectrometer magnetic
field(s) at the experimenter's discretion.

4.1a

Appendix A -- Beam induced radiation outside the enclosure

The Experimental Halls Methodology assumes a loss can occur anywhere
along a beam. The maximum shower intensity in the transverse direction
occurs when the beam impacts a chunk of steel 90cm long and 30cm
diameter. This worst case \"steel log\" is assumed in the calculation.
The Methodology places the \"steel log\" at various points along the
secondary beam, and the dose rate (DR) outside the Experimental Hall due
to the resulting shower is calculated. The formula for calculating the
dose rate is :

DR (mrem/pulse) = I \* (1x10-3) \* (1x10-2) \* {(E/1000)0.8} \*
{(0.5/Dair)2} \* 10-Rs/1.0 \* 10-Rc/2.6

where

I is the beam intensity per pulse (pulse=1sec)

E is the beam energy in GeV

1x10-3 is the number of shower particles per cm3 on the surface of the
\"steel log\"

1x10-2 is the conversion from shower particle density to mrem

Dair is the amount of air between the loss point and the measurement
point, in feet

Rs is the amount of shielding steel, as above, in feet

Rc is the amount of shielding concrete, as above, in feet

The dose rates are specified in mrem/pulse and mrem/hour. 1200 pulses
per hour are assumed. For normal (DC) running, areas outside the
Experimental Hall where there is unrestrained access must have dose
rates less than 0.05 mrem per hour

While using the worst-case \"steel log\" may not seem realistic or
reflect the make-up of the detector elements, this method does assist in
identifying areas in and around enclosures where monitoring is needed,
and where precautions must be taken to prevent such a worst case from
happening.

Note that for large objects placed in the beam line (for example,
calorimeters), the radiation that they generate is calculated using the
same equation. For these large objects, material outside the 15 cm
radius (nominally 6 inches) is counted as self shielding and is included
in, for example, the Rs reduction factor. For lead, the Rs reduction
factor, scaled by the ratio of the interaction length of lead to that of
steel is used making lead 1.47 times as effective per foot as steel.

4.1b

#  Appendix B -- Estimation of muon induced radiation in the MIPP Portakamps

Mikhail Kostin, Holger Meyer, Rajendran Raja

22-August-2003

We have estimated the yield of muons in the MIPP experimental hall due
to decay of particles produced by the MIPP secondary beams at beam
momenta of --90,-50, -5, 5,50 and 90 GeV/c. The program MARS was used to
track particles through the MIPP beamline. The tracking included
particle interaction of hadrons as well as electromagnetic particles due
to the secondary particles produced in the MIPP primary Copper target
(20cm long) as well as those produced by the uninteracted primary proton
beam. In order to obtain large enough statistics, the pions and kaons
thus produced were forced to decay to muons and each such muon given an
appropriate decay weight. The MARS simulation run was for 100,000
primary protons on target. The muons thus produced were tracked to the
plane of the MIPP secondary target close to the TPC. These muons were
then input into the Geant simulation of the MIPP experimental apparatus.
This simulation has realistic field maps for the MIPP magnets the Jolly
Green Giant and Rosie as well as realistic descriptions of the MIPP
apparatus (TPC, Chambers, Cerenkov, RICH and Calorimeters). We have also
added a realistic description of the beam dump (concrete and steel) for
this simulation. Figure 5 shows the MIPP apparatus as described in Geant
used for this simulation.

Figure 6 shows the tracks of muons as tracked through the apparatus in
Geant. The muons shown are for a negative secondary beam momentum of 90
GeV/c. Figure 7 shows the x and y positions (x is horizontal and y
vertical in the MIPP co-ordinate system. Positive z , out of the plane
of the paper is the direction of the beam) of all the muons that
intersect the z plane of the entrance of the portakamp. The muons in
this plot are unweighted . Since the weights are approximately evenly
distributed with respect to position, this plot is typical of the
distribution of the muons. The portakamp is defined as a box whose cross
section has dimensions 370cm X 500cm in x and y. The center of this box
is located at --720., 0.0 in x and y. The portakamp is located at 90.7
meters downstream of the center of the Jolly Green Giant. Table 1 gives
the muon statistics in the portakamp as a function of the beam momentum
and the expected proton intensities. Even if we run MIPP with a slow
spill of 1 second duration every 3 second, the radiation induced by
muons is seen to be negligible. It should be pointed out that current
scenario is promising MIPP one second slow spill every 60 seconds, which
is a factor of 20 less intense. We thus conclude that the muon induced
radiation is not a problem in MIPP with the current beam design and
running scenario.

# ![](media/image6.wmf){width="4.502083333333333in" height="3.410416666666667in"}

Figure 5 Geant simulation of MIPP apparatus. Beam dump and portakamp
position are shown.

![](media/image7.wmf){width="4.498611111111111in"
height="3.588888888888889in"}

Figure 6 Geant simulation of muons produced by 90 GeV/c negative beam.
Both positive and negative muons are tracked. Red track is an electron
from muon decay.

![](media/image8.wmf){width="5.995138888888889in"
height="6.027777777777778in"}Figure 7 Muon Impact points in the
portakamp plane (50 GeV/c negative beam)

Table 1: Muons entering the portakamp as a function of secondary beam
momentum and intensity. One beam spill every 3 seconds is used to
calculate the dose in the portakamp.

+-----------------------------------------------------------------------+
| +------------+-------------+-------+-------------+---------------+    |
| | ***Beam    | ## Proto    | ***   | ***R        | ***Average    |    |
| | M          | n Intensity | Muons | adiation*** | Muon***       |    |
| | omentum*** |             | in*** |             |               |    |
| |            | *           |       | ***Mrem***  | ***Momentum   |    |
| | *          | **/spill*** | ***Po |             | in***         |    |
| | **GeV/c*** |             | rtaka | ***/hour*** |               |    |
| |            |             | mp*** |             | ***portkamp   |    |
| |            |             |       |             | GeV/c***      |    |
| |            |             | **    |             |               |    |
| |            |             | */spi |             |               |    |
| |            |             | ll*** |             |               |    |
| +------------+-------------+-------+-------------+---------------+    |
| | ***5***    | 9.66E+09    | 8.0   | 2.02E-02    | 4.84          |    |
| |            |             | 1E+04 |             |               |    |
| +------------+-------------+-------+-------------+---------------+    |
| | ***50***   | 5.76E+08    | 8.8   | 2.22E-03    | 6.38          |    |
| |            |             | 1E+03 |             |               |    |
| +------------+-------------+-------+-------------+---------------+    |
| | ***90***   | 2.67E+08    | 7.9   | 2.01E-03    | 5.73          |    |
| |            |             | 8E+03 |             |               |    |
| +------------+-------------+-------+-------------+---------------+    |
| | ***-5***   | 1.49E+10    | 1.2   | 3.19E-02    | 5.41          |    |
| |            |             | 6E+05 |             |               |    |
| +------------+-------------+-------+-------------+---------------+    |
| | ***-50***  | 5.73E+09    | 3.9   | 9.88E-03    | 5.09          |    |
| |            |             | 1E+04 |             |               |    |
| +------------+-------------+-------+-------------+---------------+    |
| | ***-90***  | 7.62E+10    | 4.2   | 1.07E-01    | 5.41          |    |
| |            |             | 3E+05 |             |               |    |
| +------------+-------------+-------+-------------+---------------+    |
+-----------------------------------------------------------------------+

**5. Appendices:**

Appendix MC-1: MCenter Beam Sheet

<http://ppd.fnal.gov/experiments/e907/Beam/mipp_primary_beam_sheet.htm>

Appendix MC-2: Cossairt requirements

<http://home.fnal.gov/~chuckb/MC02.xls>

Appendix MC-3: MCenter Longitudinal Shielding Spreadsheet

<http://home.fnal.gov/~chuckb/MC03.xls>

Appendix MC-4: MCenter Transverse Shielding Spreadsheet

<http://home.fnal.gov/~chuckb/MC04.xls>

Appendix MC-5: MARS calculations by Mikhail Kostin:

<http://ppd.fnal.gov/experiments/e907/Beam/sas.pdf>

Appendix MC-6: MCenter Labyrinth and Penetration Spreadsheet

<http://home.fnal.gov/~chuckb/MC06.xls>

Appendix MC-7: MCenter Secondary Beam Sheet

<http://ppd.fnal.gov/experiments/e907/Beam/mipp_beam_sheet_8.htm>

Appendix MC-8: MIPP run conditions

[http://ppd.fnal.gov/experiments/e907/Beam/MIPP beam
needs.pdf](http://ppd.fnal.gov/experiments/e907/Beam/MIPP beam needs.pdf)

Appendix MC-9:MIPP Beam dump analysis

<http://ppd.fnal.gov/experiments/e907/Beam/beam_dump.htm>

**6. Drawings:**

MC-D1 Schematic layout of the MCenter primary beam line, M01-MC6

MC-D2 MCenter secondary beam line in MC5, MC6 and MC7, and E907

MC-D3 MC7 beam dump

(note: these drawings are included in the 3-ring binder Master Copy of
this Shielding Assessment Addendum)