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SLAC Activation Experiment February 27, 2007
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Participants
SLAC: J.Liu
J.Bauer
H.Tran
H.Brogonia
M.Kerimbaev
S.Rokni
A.Fasso
T.Sanami
V.Bharadwaj
J.Sheppard
CERN: H.Vincke
M.Brugger
S.Mallows
S.Roesler
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1) Irradiation
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a) ESA/target
- check (find) target
found old target, condition o.k.; beam will enter the flat side
(seeattached picture); dimensions and interior structure, likely
spiral groove for waterunderneath steel jacket: decided to use
new dump
4” diameter copper is available at SLAC: 10” long
Sayed: few thousand dollar for dump is o.k.
Do we need analysis of dump material?
- installation in ESA
Discussed with Dieter, Carsten, and Mike Racine:
No ILC equipment will be removed; the target will be placed at large orange holder, pretty much in the middle of the opening; two long pieces of beam pipe will be removed; the vacuum pipe will end with a 2 to 3 mil aluminum window; the beam will travel about two meters through air; the vacuum in the pipe right upstream of target will be provided by an A-Line pump; Mike and Carsten will arrange that with the relevant group (Matt); about 2 meters behind the dump the space will be completely empty.
The aluminum head of the orange holder will be modified, and the current aluminum holder will be cut down to fit the aluminum head; details are up to Dieter and Carsten; since no equipment of ILC will be removed, the whole installation will take only one shift --- as long as everything is prepared in advance. Beams would drop at 7 or 8am, then by 4 to 6pm we could start the irradiation; beams will be fine from the start, since the beams will have been well-tuned already at 8am.
-alignment; pre-experiment survey (Dieter,Carsten)
if dump turns out to be misaligned, who will align it when
(how long wait time?)
-get camera and phosphorous screen to see beam hitting dump: Dieter says Robert LaVergne Brown is the expert: Doesn’t have time; he can loan us a camera and lens (what type depends on where to mount the camera); we will ned a 110V outlet and a coax cable to a monitor. The camera would not be shielded, no mirrors, since nothing pre-made is available, and for a small experiment this would be not cost-effective. The camera has ¼” 20threads/inch female holes for mounting. Keith Jobe said Ray Arnold would know a cabinet (in ESA?) with such paper, that can be used as a phosphorous screen. Keith thinks for our purpose this is better than some paint that he has. He suggests to not put a cross-hair at the center. Sent e-mail to Dieter, Carsten, Ray.
Responsible - CERN: H.Vincke
SLAC: J.Bauer
b) Beam monitoring (100W = 2x10^9 at 10Hz)
- toroid readout, incl. format, frequency, relative/absolute accuracy,
calibration
Response from Rick Iverson (no longer involved with ESA):
toroids AB012995 fine down to 10^9, high-gain toroid 4140 (3I1)
can go about factor 10x lower
- beam profile/wire scanner: just observed or also recorded?
Rick Iverson: The two wire chambers are WIRE,AB01,4300 and
WIRE,AB01,4500; beam position is monitored by BPM,AB01,4160,4170
and bpms with localreadout into a scope (unless things changed
recently).
Carsten: Perhaps measuring profile after irradiation of each
set of samples; profile can be recorded
Wire scanner from ILC can be used: Doug McCormick: standard beam is about 1mm diameter beam or 500 to 700 micrometer sigma; the wire scanner does not provide an absolute position, but can tell quite good (up to 2/10th of a micrometer) how far the beams shifted between scans (at the scanner location, not necessarily at the dump). The scanner uses standard software that the operators know how to use; it has to run at 10 Hz at least. Low beam power makes things difficult; perhaps Mike Woods knows at what current the last scans in July were. I shall talk with Mike Woods on what ILC is planning to do during their experiment, and perhaps one can prepare a new wire card with 120 micron-wide instead of 75 micron-wide wires. If one prepares this early, swapping out the card would take only twenty minutes. Wider wires would give a stronger signal at low beam currents. Ask Mike Woods about scanner and wire card.
Talked with Zen, Bob Simmons, Kasey Traeger, Ray Arnold; toroid 4140 can easily measure down to 10^9 e-/s, but needs repair. Kasey: won’t have time to fix it; no answer yet from Ray Arnold.
Mike Woods: Wire scanner should be able to read down to 2x10^9 without modification. We should perhaps wait with putting the samples in until beams are established and feedback is turned on. No problem to then turn the beam off for a shift or so. Feedbacks should be running all the time, work better at 10 Hz, but 1 Hz still good, and perhaps one can sometimes raise the rate to 10 Hz to get beam stable again. One can also do a wire scan to see how beams shifted. One has to be in ESA counting house only for putting screens in, PR2, for example. The picture can be viewed from MCC, but the controls are only in ESA. One may rather stay in MCC for better communication, while going to ESA only for these screens. In principle one could also keep the screens in, but then backgrounds would be higher. Wire scan can be done from MCC alone. It is good if one person is at MCC to keep flow of information running. He thinks the 4140 toroid is working, was working in July, and gives reasonable values. If it is working, it is good to about 10%, o.k. perhaps 5% and in principle to 1%. We’ll know next week whether it is working. The calibration would be done by Kasey and Bob or someone they mention.
Carsten: doesn’t see a problem, gave a few numbers, but exact
Information needed, including how to use the equipment.
Says ILC beam experiment will determine a nice tuning of our beam;
will follow up soon withCarsten and Ray
Talked with Anthony Tilghman (supervisor of Bob Simmons and Kasey Traeger): I stressed that we need beam monitoring, calibrated, don’t care which toroid is used; that this is crucial to our experiment; he said today (3/5/07) will be meeting on work load, involving LCLS Injector Phase I and II, and also other work will be discussed.
How can the current be limited for safety?
Paul Miller: ACMs, buttalk to Bob Simmons on limit
Can trip level of 3C2 be raised? Paul Miller: He’ll have to look
it up.
Responsible - CERN: H.Vincke
SLAC: J.Bauer
c) Sample support
-lateral, downstream holder(?)
Dieter offers to build something small;
Markus: plastic boxes like in previous experiment
Stefan: place samples as close as possible
Have now agreement on sample size and shape, number,
locationin r and z relative to dump, material will be
aluminum
Carsten: Provide drawing of what we want
Nalgene bottles to Dieter
Responsible - CERN: H.Vincke
SLAC: J.Bauer
d) Samples
- CERN: copper, iron, aluminum, titanium, stainless steel,
concrete
CERN samples analyzed
- SLAC: soil, demineralized water, tap / creek water,
concrete(SLAC type):
James will get samples out for analysis
- ILC samples: long-term sample, one long-term sample?
perhaps in the end placed into beam?
-stamp samples or otherwise mark uniquely; similar with bottles
- define size (SLAC-GS?), positioning around target
Need agreement on samples so that sample holder can be prepared:
discussion with CERN soon (seems to be agreed on)
Markus: 1x1x1cm or 0.5x0.5x0.5cm (machining more difficult?
chemical composition still the same?); depends on
activityand detector sensitivity
Pour water into clean bottle?
2x2x2cm for dose, 2x2x0.2cm for activation
Soil, water, concrete in 500 ml Nalgene bottles
- order, preparation, analysis and shipment
Markus: bring maximum amount; machining possible;
Responsible - CERN: M.Brugger
SLAC: J.Liu
e) Permissions
- Approval of proposal
Done
- Scheduling with Roger Erickson
~ March 1: end of major installation work inside ESA
March 7 - 26: ILC beam tests
(above dates possibly shifted by ~ 1 week)
March 29 or earlier: setup of our experiment
March 30 day shift: beam tuning
March 30 to April 4: beams for our experiment
Seems everyone is happy with 16 shifts of beam
- General safety analysis
Carsten: start with sketch, first: dump holder?
Carsten: Talk with Ken Moffeit to get feedback from committees
Ken: Talk with Clive; he has to request such action from
Safety Overview Committee
Clive: No such action needed, just RP approval & BAS needed, and
Carsten will watch for issues on installation
- JHAM
- RP approval
Information with Alyssa;starting RP note (Johannes – induced
dose, procedure, safety and shift training, schedule);
calculations (Alyssa – independent from collaborators, focus
on dose to outside);
Presentation around 2/28 to RP group:
covering prompt and residual radiation;
include procedures and requirements (work with Jim Allan)
Using toroid readings to ensure only 100W are dumped?
No ion chamber needed? Upstream collimators ensure
beam cannot go astray?
Air activation: waiting for answer from Henry
Report will be reviewed by Stan, then submitted to chairs
of RSC and ALARA, who will decide on possible committee meeting
Responsible - CERN:
SLAC: J.Bauer
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2) Gamma spectrometry measurements
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a) Gamma spectrometers
- calibration (once a shift), characterization,efficiency, accuracy,
quality assurance; background measurement before experiment
- tape to stop beta+ emitters?
- analysis software
Modeling?
- user-defined libraries
See attached e-mail from Henry Brogonia
Responsible - CERN: M.Brugger
SLAC: H.Brogonia/J.Liu
b) Availability and schedule
- Two HEGe spectrometer, one Transpec, available most of the time, but
one might be needed for field operations
- See attached e-mail from Henry Brogonia
-Effect on irradiation schedule
Responsible - CERN: M.Brugger
SLAC: H.Brogonia/J.Liu
c) Data analysis
- at SLAC (and CERN?), software needs
Responsible - CERN: M.Brugger
SLAC: H.Brogonia/J.Liu
d) Laboratory
- low-background lab
establish lead cave on floor for Transpec
- sample holder
James talked with Henry Brogonia,
Henry B. will talk with Dieter about holders
(cost for sample holders few 100 dollars)
- measurement configurations, distances,...
- instructions how to use instruments including list of what to record
Responsible - CERN: S.Mallows
SLAC: J.Liu/H.Brogonia/
M.Kerimbaev
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3) Dose rate measurements
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a) Microspec (CERN unit)
- test, calibration and background measurement before experiment
- Atari computer as backup (ebay/Heinz)
- shipping (verify needs at CERN during the period)
- comparison with SLAC SAM etc.?
Responsible - CERN: S.Mallows
SLAC: J.Liu
b) BNC SAM935 (CERN & SLAC unit) + extl detector will not have it
- test demonstration unit beg. of Feb. at CERN
- software and readout / Laptop
- compare with Microspec
- verify SLAC device (SLAC SAM, ion chamber, GM counter)
- calibration with Cs source, test with other sources
Responsible - CERN: S.Mallows
SLAC: J.Liu
c) Laboratory
- low-background lab
establish lead cave on floor
- sample holder
same issues as for GS measurement
- measurement configurations, distances,..
- instructions how to use instruments including list of what to record
Responsible - CERN: S.Mallows
SLAC: J.Liu/H.Brogonia/
M.Kerimbaev
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4) SHIFTS
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a) Safety training
- General SLAC training
Jim Allan: will provide material for courses:
GERT
RWT-I/II
LRCA=Limited Radiological Control Assistant
will need two days
- Controlled access training
Carsten: visitors allowed alone in hall with training
- Sample exchange, handling and transportation: gloves? booties?
Responsible - CERN: S.Roesler
SLAC: J.Bauer
b) Shift Logistics
- transportation during experiment: boxes, car
- space to store samples in lab
- list of phone numbers
- permission to stay in lab overnight?
Responsible – CERN:
SLAC: J.Liu
b) Shift training
- Interfacing with MCC
Carsten: likely sitting at MCC; will need to find out more
- Procedure of sample change: safety, records
- Rehearse sample exchange
- Agreement on experimental protocol: What to record, when to
request wire scan, what to do if ... Two people in ESA
(Paul Miller: MCC won’t be able to help at night)
- RPFO support: initially and intermittently
- Gamma spectroscopy and dose measurement training
Responsible – CERN:
SLAC: J.Bauer
c) Schedule and Logbook
- irradiation schedule
table with planned schedule (see schedules/ShiftSchedule.pdf)
about 45’ of no beam each time during sample change
create table of quantities to record during beam shifts
- GS and dose rate measurements
create table of quantities to record during counting shifts
Responsible - CERN: S.Roesler
SLAC: J.Bauer
d) Manpower
SLAC (subject to approval by Sayed):
Beam shifts: 4 to 6 people
Dose/Spectrometry Measurements: ~3 (mainly weekday day shifts)
CERN:
Beam shifts: 1 person
Dose/Spectrometry Measurements: 3 people
Stefan: fewer people will be needed like 5 FTE
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5) Monte Carlo simulations
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a) In preparation
- dose estimate for sample exchange
Stefan provided first numbers; see Stefan’s slides
(ppt/20070208_Persis_RP.ppt)
Stefan will prepare numbers for new dump
- dose estimate for concrete and surrounding equipment
Done, Stefan provided numbers
- prepare user-defined library, prepare geometry, and estimate dose
rate for samples in advance
Responsible - CERN: S.Mallows / S.Roesler
SLAC: J.Liu / A.Fasso
b) Benchmarks
- FLUKA
- other codes (MARS?)
Responsible - CERN: S.Mallows / S.Roesler
SLAC: J.Liu / A.Fasso
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6) Logistics
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a) Shipping CERN-SLAC
- samples, Microspec
- shipping to SLAC and back after experiment
Responsible - CERN: S.Roesler
SLAC: J.Bauer
b) Laptop / Camera
Laptop:
Camera: RP camera available
Good clock needed?
Responsible - CERN: S.Roesler
SLAC: J.Bauer
c) Travel
-who, when, budget, car
Who:
Markus: March 19 to 29
Heinz and Stefan: March 24 to April 5
Sophie: March 21 to April 5
-visa:
International Office (Robyn Mosset):
Read web sites:
Might need invitation letter (definitely if in for more than
5 days and getting reimbursed by SLAC); check with Sayed
about it. Invitation letter will also help at port of entry.
Might need to check in with international office.
WB visa if part of visa waiver program, otherwise B1/B2
-Computers/desks/
Let Betty know once travel dates are firm.
Ask Sayed where the visitors will stay
(so that atom can be correctly assigned)
Have them sign computer account forms.
- Lodging
guest house?
Responsible - CERN: S.Roesler
SLAC: J.Bauer
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7) Miscellaneous
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a) Contact w/ ILC
ILC people (V.Bharadwaj, J.Sheppard) joined us
- ILC samples: long-term samples of Ti alloy for dose and
Activity will be prepared by Dieter; they will analyze it?
- Contribution to shifts: yes
Responsible - CERN: H.Vincke
SLAC: J.Bauer
Old Dump: 10” long, 5” diameter, beam coming from left; bottom will
be modified
Looking upstream: Gray stand holds the wire scanner;
orange legs will hold the dump
Looking downstream; gray stand holds the wire scanner; orange stand
in the center will hold target
From: Brogonia, Henry C
Sent: Wednesday, February 07, 2007 12:08 PM
To: Liu, James C.
Cc: Kerimbaev, Murat
Subject: RE: questions on samples for ESA experiment
James,
Please review:
Samples
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Because we have calibration files for the following matrices SLAC can prepare samples of soil, concrete, and water. These will be placed in 500 ml Nalgene bottles with a volume similar to our calibration standards. If there are any objections please let us know.
Samples of other materials can be prepared to your satisfaction. We do not have calibration standards for other materials, so there will be a need to plan on performing corrections (modeling software or purchase/create similar standards).
Gamma Spectroscopy
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(1) number & efficiency of the detector
We have two fixed HPGe detector systems (one p-type 40% relative efficiency, and one n-type 50% relative efficiency). Both detectors are mechanically cooled. One system works on NimBin electronics and the other is running on a DSPEC Pro. All equipment (cooler, electronics, detectors, and software) except some NimBin parts are from ORTEC. In addition we also have two portable gamma spec systems, a Transpec from ORTEC and a SAM unit from BNC. We will be configuring a cave for the Transpec as a possible third detector for counting. Our SAM unit will only be used for dose rate comparisons.
(2) calibration, accuracy & quality assurance & (3) characterization of the detector -> modelling of samples (like ISOCS)
Our GS system is used a few times a week and a QA check is performed daily when in use. In addition SLAC participates in an intercomparison study for QA purposes. Calibrations are performed once a year. During this time the energy/efficiency curves are also created (we do not use any vendor supplied efficiency curves). These curves are based on two standards used to count our environmental samples (500 ml epoxy in Nalgene bottle with sample on detector geometry and a 250 ml sand matrix in Nalgene bottle with sample on detector geometry). We will also provide a shelving system for the detectors in case we need to count samples at various distances. We can work with you to determine which distances should be used. The Gamma Spec software (Gammavision) can provide some geometry corrections.
The detectors sit in a non air-conditioned room, but with tinted windows and blinds (temperature variability should not be an issue, especially during March). Although we normally do not perform any background subtraction, we can acquire background spectra (empty cave and matrix
background) if necessary.
(4) availability and schedule
GS systems directly support field operations, so there may be instances where a field sample must be counted right away. However these are rare occasions so the GS system should be available during the entire ESA experiment. Because our detectors are mechanically cooled, there is no need for LNO filling and QA should take approximately half-hour each day. Analysis/post processing can be performed on a separate computer so the detectors may be used without interruption.