Difference between revisions of "Wednesday October 2, 2013"

Latest revision as of 10:13, 23 December 2015

We will meet in TED 2561B on Wednesday October 2 at 3:00 pm EST.

For those calling in we'll use the ReadyTalk audio conference system.

1. Dial Toll-Free Number: 866-740-1260 (U.S. & Canada)
2. Enter 7-digit access code 4402297, followed by “#”

Agenda:

1- Bubble Chamber progress at Argonne

2- Computer Center support: mailing list, group disk, wiki page, ...

3- Cost:

 - Indirect General and Administrative (G&A) cost: 55.65% for both labor and procurement (Material and Shop)
 - Indirect Statutory and Fringe for labor: 57.15%
 - Final Bubble Chamber cost media:Bubble_FinalCost.pdf media:Bubble_FinalCost.pptx

4- Error Analysis:

 - Analytical: Statistical, Absolute and Relative Systematic Errors media:Bubble_ErrAna.pdf media:Bubble_ErrAna.pptx
 - Monte Carlo Technique: Statistical, Absolute and Relative Systematic Errors media:Bubble_ErrAnaMC.pdf media:Bubble_ErrAnaMC.pptx
 - Root macro files used in error analysis study (change txt to tar): media:ErrorAna.txt

Notes from this meeting:

Bubble Chamber:

- The State of Virginia reporting limit for mercury brought on-site is 5.0 lbs. This is about 2268 grams or 168 mL.
- Distance from the Bremsstrahlung radiator to the center of the bubble chamber must not exceed 50 cm. The Bremsstrahlung
photon beam has a large opening angle at this low electron beam energy and thus the photon flux drops very quickly with distance.
- JLab will high-pressure test to 100 atms a cylindrical fixture (called Phase Separator, will be used to hold mercury).

Submitted a request to JLab Computer Center for a new mailing list and group. Our name is "bubble".

- Mailing List: bubble@jlab.org
- Group: bubble
- Group Disk: /group/bubble
- Work Disk: /work/accel/bubble
- Bubble experiment is set up for farm use with 500GB work storage; please use project bubble for your jobs (Group account: accelerator).

Cost:

- The grand total loaded cost is about $360k. 
- Is it possible for our procurement cost to be considered "Capital Equipment"?

Error Analysis:

- Bubble Chamber Efficiency Systematic Error: This error accounts for the fact that there will be a threshold on bubble formation
in the superheated fluid. This threshold depends on the pressure and temperature of the fluid and will be used to reject low energy
ions from the reaction ¹⁴N(γ,p)¹³C and from neutron elastic scattering. For the reaction ¹⁴N(γ,p)¹³C, we need at least 10⁸ suppression.
- It is very important to have the systematic errors being relative, i.e., these errors do not change from one energy to another.
Some of the systematic errors are clearly relative like radiator thickness or chamber thickness errors. For others, we have to 
make sure that they are relative. For example, when we do the energy scan, we need to change the beam energy by exactly 0.1 MeV
without changing or introducing any new factor that would affect the beam energy systematic error. Also we do not want to change
the beam position or size on the radiator when changing beam energy.
- Relative systematic errors do not get amplified with Penfold-Leiss unfolding.

@@ Line 5: / Line 5: @@
 . Enter 7-digit access code 4402297, followed by “#”
-Agenda:
+'''Agenda:'''
 - Bubble Chamber progress at Argonne
@@ Line 19: / Line 19: @@
    - Analytical: Statistical, Absolute and Relative Systematic Errors [[media:Bubble_ErrAna.pdf]] [[media:Bubble_ErrAna.pptx]]
    - Monte Carlo Technique: Statistical, Absolute and Relative Systematic Errors [[media:Bubble_ErrAnaMC.pdf]] [[media:Bubble_ErrAnaMC.pptx]]
+  - Root macro files used in error analysis study (change txt to tar): [[media:ErrorAna.txt]]
 ----
-Notes from this meeting:
+'''Notes from this meeting:'''
 * Bubble Chamber:
-  - In the process of changing the buffer liquid from water to mercury (volume = 100 ml). Mercury will be in a sealed system that
+  - The State of Virginia reporting limit for mercury brought on-site is 5.0 lbs. This is about 2268 grams or '''168 mL'''.
-  will allow for changing the active liquid without the need to remove or add mercury.
+ - Distance from the Bremsstrahlung radiator to the center of the bubble chamber must not exceed 50 cm. The Bremsstrahlung
-  - Mercury does not tolerate all other metals except for iron. However, CF iron gaskets will destroy the knife edges.
+  photon beam has a large opening angle at this low electron beam energy and thus the photon flux drops very quickly with distance.
- Still looking for a solution.
+  - JLab will high-pressure test to 100 atms a cylindrical fixture (called Phase Separator, will be used to hold mercury).
-  - The new design of the chamber will fit in the space between beamline and floor in the Injector (27 inches).
-  - Adding acoustic signal readout to the chamber.
+* Submitted a request to JLab Computer Center for a new mailing list and group. Our name is "bubble".
-  - For <sup>17</sup>O superheated target (needed to measure background), the ratio of <sup>17</sup>O nuclei to <sup>18</sup>O nuclei should be greater than 100.
+  - Mailing List: bubble@jlab.org
-  Note that the thresholds and cross sections for the reactions: <sup>17</sup>O(γ,α)<sup>13</sup>C and <sup>18</sup>O(γ,α)<sup>14</sup>C are very similar.
+  - Group: bubble
-  - For <sup>18</sup>O superheated target (needed to measure background), the ratio of <sup>18</sup>O nuclei to <sup>17</sup>O nuclei should be greater than 100.
+  - Group Disk: /group/bubble
+  - Work Disk: /work/accel/bubble
+  - Bubble experiment is set up for farm use with 500GB work storage; please use project '''bubble''' for your jobs (Group account: accelerator).
 * Cost:
-  - Will pass the Bubble Chamber cost estimate by Jefferson Lab Finance to get more realistic labor, procurement and shop costs
+  - The grand total loaded cost is about $360k.
+ - Is it possible for our procurement cost to be considered "Capital Equipment"?
-* Beamline Layout:
+* Error Analysis:
-  - We will not install a new BPM on the Spectrometer line since we have no way to know the absolute positions. The Bubble
+  - Bubble Chamber Efficiency Systematic Error: This error accounts for the fact that there will be a threshold on bubble formation
- Chamber beamline will be equipped with two BPMs and two Super Harps that will be used to measure the beam energy.
+ in the superheated fluid. This threshold depends on the pressure and temperature of the fluid and will be used to reject low energy
-  - We need to think very carefully if we need a vacuum pipe that connects the vacuum window to the Bubble Chamber. Would it
+ ions from the reaction <sup>14</sup>N(γ,p)<sup>13</sup>C and from neutron elastic scattering. For the reaction <sup>14</sup>N(γ,p)<sup>13</sup>C, we need at least 10<sup>8</sup> suppression.
-  add more protection to the vacuum window? Now, there is a risk of contaminating the beamline with oil. How to fit in the photon
+  - It is very important to have the systematic errors being relative, i.e., these errors do not change from one energy to another.
-  collimator? Any issues with alignment? Pumping on the vacuum pipe may introduce vibrations that may trigger the acoustic sensors.
+ Some of the systematic errors are clearly relative like radiator thickness or chamber thickness errors. For others, we have to
+ make sure that they are relative. For example, when we do the energy scan, we need to change the beam energy by exactly 0.1 MeV
+  without changing or introducing any new factor that would affect the beam energy systematic error. Also we do not want to change
+ the beam position or size on the radiator when changing beam energy.
+  - '''Relative systematic errors do not get amplified with Penfold-Leiss unfolding.'''

Difference between revisions of "Wednesday October 2, 2013"

Latest revision as of 10:13, 23 December 2015

For those calling in we'll use the ReadyTalk audio conference system.

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