Difference between revisions of "PosRun 10 14 2013"
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===Shielded Cell direct beam with magnet=== | ===Shielded Cell direct beam with magnet=== | ||
| − | reconfigure with magnet in shielded cell to deflect charged particles towards NaI detector #3, | + | reconfigure with sweep magnet in shielded cell to deflect charged particles towards NaI detector #3, |
{| border="1" |cellpadding="20" cellspacing="0 | {| border="1" |cellpadding="20" cellspacing="0 | ||
| Line 78: | Line 78: | ||
| 6513 || min s ( pulses) || dipoles in electron mode transporting 6 MeV, Magnet is IN and deflecting positrons towards NaI | | 6513 || min s ( pulses) || dipoles in electron mode transporting 6 MeV, Magnet is IN and deflecting positrons towards NaI | ||
|- | |- | ||
| − | | 6514 || min s ( pulses) || same as last run except: dipoles in positron mode | + | | 6514 || 12 min 3 s ( pulses) || same as last run except: dipoles in positron mode, doubled current from last run |
| + | |- | ||
| + | | 6515 || min s ( pulses) || same as last run except: positron dipoles set to 8 MeV, increased current and rep rate (150 Hz) | ||
| + | |- | ||
| + | | 6516 || min s ( pulses) || same as last run except: positron dipoles set to 6 MeV, | ||
| + | |- | ||
| + | | 6517 || 2 min 18 s ( pulses) || same as last run except: Magnet is out | ||
| + | |- | ||
| + | | 6518 || 7 min 10s ( pulses) || same as last run except: positron dipoles set to 8 MeV, sweep Magnet is out | ||
| + | |- | ||
| + | | 6519 || min s ( pulses) || same as last run except: sweep Magnet is In positron bending mode | ||
| + | |- | ||
| + | | 6520 || min s ( pulses) || same as last run except: sweep Magnet is In electron bending mode | ||
| + | |- | ||
| + | | 6521 || min s ( pulses) || same as last run except: dipoles set to electron mode | ||
|} | |} | ||
| + | |||
| + | |||
| + | 38 MeV electrons with 859 pVs/50 Ohms per 100 nsec wide pulse | ||
| + | |||
| + | a scope measurement of the 38 MeV electron pulse impinging the tungsten target suggested that one pulse had | ||
| + | |||
| + | <math>\frac{0.859 \times 10^{-9} V s}{50 Ohm} = 1.7 \times 10^{-11} Coul \frac{1 e^-}{1.6 \times 10^{-19} Coul} = 10^{8}</math> electrons | ||
| + | |||
| + | or given the 100 nsec pulse width the peak current is | ||
| + | |||
| + | <math>\frac{1.7 \times 10^{-11} Coul}{100 \times 10^{-9} sec}</math> = 0.017 Amps | ||
| + | |||
| + | I believe we need to run at 0.01 Amps to keep the ion pumps working. | ||
| + | |||
| + | |||
| + | [[File:PosRes_10-15-2013.png | 200 px]][[File:PosResA_10-15-2013.png | 200 px]] | ||
==FC -vs- 90A beam stop correlation== | ==FC -vs- 90A beam stop correlation== | ||
Latest revision as of 20:49, 16 October 2013
Run list
Scaler channel #2 counts the number of beam pulses
Detector 4 is Beam Left and in ADC channel 7, Ortec Dual Spec amp set to course=10, fine=39, Canberra CFD set to 85 mV lower threshold
Detector 1 is Beam Right and in ADC channel 3, Ortec Dual Spec amp set to course=20, fine=10, Canberra CFD set to 70 mV lower threshold
In-flight
| Run # | Run Duration (s) | Configuration |
| 6488 | min s | 2->60Hz rep rate, Looking at NaI in shielded cell at -600 Volts, Magnet on Accelerator side deflects electrons, Tungsten target is out, triggering only on the beam gate and looking at ADC channel 3 |
| 6489 | min s | same as above except: 120Hz rep rate, -500 Volts, |
| 6490 | min s | same as above except: -550 Volts, |
| 6491 | min s | same as above except: -575 Volts, |
| 6492 | min s | same as above except: inserted Aluminum brick to be sure electrons are staying on accelerator side, drops NaI output by factor of 2 |
| 6493 | min s | same as above except: -600 Volts |
| 6494 | min s | same as above except: -700 Volts |
| 6498 | min s | same as above except: -500 Volts, magnet out |
| 6499 | min s | same as above except: -700 Volts, very similar ADC spectrum for magnet in |
| 6500 | min s (54420 , 120 Hz pulses =453.5 sec) | same as above except: removed Al brick beam stop, increased current from zero until signal was observed in experimental cell NaI (probably mostly dark current from RF cavity) |
| 6501 | min s (54297 pulses) | same as above except: inserted Al brick beam stop, 
|
| 6502 | min s (54297 pulses) | same as above except: REmoved Al brick beam stop |
40 MeV on Tungsten
40 MeV electrons are hitting the positron production Tungsten target
| Run # | Run Duration (s) | Configuration |
| 6503 | 3 min 46 s ( pulses) | Dipoles in positron mode. Al Brick in along 8 inch length |
| 6504 | min s ( pulses) | same as previous run, Al brick OUT |
| 6505 | min s ( pulses) | same as previous run, Dipoles in Electron mode, 
|
| 6506 | min s ( pulses) | same as previous run, Selection Magnet bending electrons up positioned after 50 micron Ti vacuum window, 
|
| 6507 | min s ( pulses) | same as previous run, dipoles set to positron mode and selection magnet rotated 180 degrees so positrons bend up, |
| 6508 | min s ( pulses) | same as previous run:increase voltage from -700 to -850 |
| 6509 | min s ( pulses) | same as previous run, installed 2" thick graphite hardener |
| 6510 | min s ( pulses) | same as previous run, removed graphite hardener and selection magnet, returned to dipoles in electron mode, |
Shielded Cell direct beam with magnet
reconfigure with sweep magnet in shielded cell to deflect charged particles towards NaI detector #3,
| 6511 | min s ( pulses) | dipoles in electron mode transporting 8 MeV, NaI at -700 Volts |
| 6512 | min s ( pulses) | dipoles in electron mode transporting 6 MeV, Magnet is OUT |
| 6513 | min s ( pulses) | dipoles in electron mode transporting 6 MeV, Magnet is IN and deflecting positrons towards NaI |
| 6514 | 12 min 3 s ( pulses) | same as last run except: dipoles in positron mode, doubled current from last run |
| 6515 | min s ( pulses) | same as last run except: positron dipoles set to 8 MeV, increased current and rep rate (150 Hz) |
| 6516 | min s ( pulses) | same as last run except: positron dipoles set to 6 MeV, |
| 6517 | 2 min 18 s ( pulses) | same as last run except: Magnet is out |
| 6518 | 7 min 10s ( pulses) | same as last run except: positron dipoles set to 8 MeV, sweep Magnet is out |
| 6519 | min s ( pulses) | same as last run except: sweep Magnet is In positron bending mode |
| 6520 | min s ( pulses) | same as last run except: sweep Magnet is In electron bending mode |
| 6521 | min s ( pulses) | same as last run except: dipoles set to electron mode |
38 MeV electrons with 859 pVs/50 Ohms per 100 nsec wide pulse
a scope measurement of the 38 MeV electron pulse impinging the tungsten target suggested that one pulse had
electrons
or given the 100 nsec pulse width the peak current is
= 0.017 Amps
I believe we need to run at 0.01 Amps to keep the ion pumps working.
FC -vs- 90A beam stop correlation
FC = Aluminum brick 2" from exit window near NaI detectors
50 Ohm scope termination
| 90 A BS (nVs) | FC (nVs) |
| 47 | 25 |
| 24 | 11.9 |
| 13 | 6 |
| 6.1 | 2.3 |
| 4.8 | 1.8 |