THGEM#9 Counting Experiment test 1/4/13

The same setup above for THGEM#9 is used for a counting experiment.

The aim is to compare the number of counts in an hour for three different cases:

case 1-The alpha source's shutter is closed.

case 2- The alpha source's shutter is closed and a gamma source (Co-60) placed on the detector's entrance window.

case 3-The alpha source's shutter is open the gamma source is removed

case 4-The alpha source's shutter is open and a gamma source (Co-60) is placed on the detector's entrance window.

V_cathode	THGEM_1T	THGEM_1B	[math]\Delta V1 [/math]	THGEM_2T	THGEM_2B	[math]\Delta V2 [/math]	THGEM_3T	THGEM_3B	[math]\Delta V3 [/math]
4200	2950	2450	500	1950	1200	750	950	100	850

Experimental Setup

Trigout-> 474 ortec timing filter amp. -> EGG&G ESN CF4000-01 discriminator (5 mV threshold) -> tennelec TC534 counter and timer.

case #	case 1	case 2	case 3
counts/hr	462	2400	2759

According to the number of counts in each case:

1- The detector detects cosmic rays (noise). (assuming the shutter stops all the alpha particles without any ionization)

2- The detector is sensitive to gamma rays (2400-462 = 1938)

3- The detector is sensitive to alpha particles (2759-462 = 2297) considering the same assumption above.

Discriminator level-count level relationship

V_cathode	THGEM_1T	THGEM_1B	[math]\Delta V1 [/math]	THGEM_2T	THGEM_2B	[math]\Delta V2 [/math]	THGEM_3T	THGEM_3B	[math]\Delta V3 [/math]
4359	2950	2450	500	1950	1200	750	985	100	850

The following table represent the discriminator level and the count rate that is measured in 10 minute time interval with the shutter OPEN and 474 ortec timing filter amp. amplification is x6.

discriminator level	Counts/min
(mv)	Trial 1	trial 2	Trial 3	Trial 4	trial 5	Ave [math]\pm[/math] err
5	80.7	104.2	67.4	64.5	72.8
7	96.6
8
9	36.8
10
12	11.2
13
15	5.1
18	3.7
20	3.2
50	0
75	0.1
100	0

Counting Experiment using Leading Edge discriminator (Lecroy 623b)

The same setup above for THGEM#9 is used for a counting experiment.

The aim is to compare the number of counts for three different cases:

case 1-The alpha source's shutter is closed.

case 2- The alpha source's shutter is closed and a gamma source (Co-60) placed on the detector's entrance window.

case 3-The alpha source's shutter is open the gamma source is removed

case 4-The alpha source's shutter is open and a gamma source (Co-60) is placed on the detector's entrance window.

V_cathode	THGEM_1T	THGEM_1B	[math]\Delta V1 [/math]	THGEM_2T	THGEM_2B	[math]\Delta V2 [/math]	THGEM_3T	THGEM_3B	[math]\Delta V3 [/math]
4200	2950	2450	500	1950	1200	750	950	100	850

The amplifier amplification affect the count rate, the follwing table shows the effect as the discrimination level is 1.19V :

Amplification	Count rate (Count/min)
x10	1.37x10^7
X6	1151
x4	9
x2	1
x1	1

based on the above table, the amplification is chosen to be x6 for the measurement below.

case #	case 1	case 2	case 3	case 4	Notes
counts/min	1.55 x 10^7				disc. level = 0.30V (700 mV sq.p-p)
counts/min	2.08 x10^6				disc. level = 0.53 mV (1.8V sq.p-p)
counts/min	6902				disc. level = 1.1 V (3V sq.p-p)
counts/min	3222				disc. level = 1.2 V
counts/min	1469				disc. level = 1.3 V
counts/min	680				disc. level = 1.4 V
counts/min	113				disc. level = 1.5 V
counts/min	64	84			disc. level = 1.62 V (4V sq.p-p)
counts/min	10	11			disc. level = 1.7 V
counts/min					disc. level = 1.8 V
counts/min	10	9			disc. level = 1.9 V
counts/min	7	9			disc. level = 2 V

Alpha-Beta detector counter

GEM before modification

GEM detector was operated without U-233 source inside the chamber, the detector's counting rate relationship with the applied voltage on the cathode was investigated and the result is shown by the following figure:

In the counting experiment, P.S. discriminator was used to discriminate againt the noise, the relationship between the count rate and the discrimination level (without changing the applied voltages on GEM cards and the cathode. The data is represented by the following figure:

The detector signal detected when the voltage on GEM HV-circuit was 2800V, but it was lower the noise, but raising up the voltage to 3000 V made the signal higher than the noise. So all the previous measurements observed ast he GEM HV-circuit was 3000V.

GEM after modification

A new cathode with thin layer of U-233 and its a FR4 shutter were added to the chamber, the distance of cathode is 8mm from the first GEM card, the distances between the GEM cards have equal distances to the ones before the modifications.

The VFAT connectors are connected together to provide the signal of the signal of the readout plate.

A signal is observed (on trigout and readout)as the voltage magnitude on the GEM HV-voltage circuit is 2800V, and the cathode is 3100V.

Prelimanry count rate measurements were recorded using 474 time filter amplifier, P.S. 710 discrimonator (at 0.7V) and a counter in the following table:

Shutter location	Counts/min
close	2049	2500
open	6561	6360

The high rate of counts observed as the sutter is close is due to the U-233 beta decay as shown in the figure:

Two Counter Counting Experiment

Two counters were used for counting the detector signal after installing U-233 inside the detector. The signal detected by the trigout was an input for P.S. eight channel variable gain amplifier (model 777) that had two outputs fed two types discriminators; EG&G-EN CF4000 Constant Fraction Discriminator and P.S. octal leading edge discriminator (model 710). The discrimination level of each of them allowed one of the counters (ortec 875) to count for all the amplified signal pulses produced as the shutter was close, simultaneously, the second counter to count for them as the shutter was open. (The CFD D.V. was 0.025V and 6x 474 Ortec TFA , LED D.V. was 1.52V and 1x TFA)

Due to the lower pulse amplitude for the alpha particles the higher one for negative beta, decrease the detector gain may help in counting for alphas and fission fragments without counting for beta particles. Or we can use Ortec 552 (pulse shape analyzer and timer) with ortec 460 (delay shaping line amplifier).

Counting started by the lowest voltage alpha signal is observed (2.6 kV, 2.9 kV), an ortec 474 is used and it amplifies the signal up to 6x.A leading edge P.S. 710 octal discriminator is used with a discrimination level of 150 mV.

GEM performance data graphs

U-233 fission x-section data

What is the energy distribution of Beta and Photon from U-233

Gamma distribution for U-233 and its daughters are in metioned in details in the documents , File:U233 day gamma.pdf <ref>http://www.radiochemistry.org/periodictable/gamma_spectra , Wed. 04/10/2013</ref>

The energy range of the emitted gamma is shown in the following table .

nuclide	Energy Minimum	Energy Maximum (keV)
U-233	25	1,119
Ra-225	40	40
Ac-225	10.5	758.9
Fr-221	96.8	410.7
At-217	140	593.1
Bi-213	323.81	1,119.4

Negative beta particles are emitted mainly from U-233 daughters as shown in the figure <ref> http://itu.jrc.ec.europa.eu/index.php?id=204, Wed. 04/10/2013 </ref>

The following table shows the negative beta emitter nuclides,their parent nuclides, and their half lives:

Nuclides	energy (MeV)	half life
	0.357	14d.
	1.426	46min.
	1.981	2.2 min.
	0.644	3.25h
[math]Bi^{209}[/math]	1.893	stable

What is the energy distribution after the 1 mm FR4 shutter

electrons

The energy distribution below represents the incidence electron on a 1 mm FR4 shutter.

The energy distribution of photons was observed on the opposite side of the shutter

Electrons (with least energy from U-233= 0.2 MeV) pass through the shutter have the energy distribution below.

photons

Number of ions produced from Beta and Photon in ArCo2

EMTest10 is used to calculate the average number of ions (electrons) when a 101 beta of 1 MeV are fired in a world that contains ArCO2. (13.5 per primary electron).

Calibrating GEM detector

Time to observe the GEM signal

In the case of triple GEM detector with a gas flow of 0.3 SCFH and 2650V and 2950V on GEM cards and cathode successively, a signal lower than the noise (of 16 mV and amplified twice) is observed at 770.0s +/- 0.1.

The normal rate (8 MHz +/- 2 as measured by the oscilloscope) is observed after 952.9s +/- 0.1.

THGEM card tasks and tests

New THGEM cards

Two new fully machined cards are going to be tested in air and ArCH4, if they passes 2000 V potential bwtween the top and the bottom, then they are going to be installed in ArCh4 gas chamber.

The older THGEM cards will have a high voltage enough to have one spark/min to clean impurities or surface defects.

References

THGEM design

THGEM#9

Media:Shalem_MSthesis_march2005.pdf

Media:Raz_Alon_MSthesis_Dec2007.pdf

Electric field Simulation

Rim size dependence

File:THGEM Efield simulation.pdf

2010 THGEM design(s)

File:THGEM 2009 design gas efficiency.pdf

Simulations_of_Particle_Interactions_with_Matter

Voss and 3 russian references for Dy(n,x) cross sections

http://arxiv.org/abs/0903.3819 Dy photon gammas spectrum

http://www.ippe.obninsk.ru/podr/cjd/kobra13.php?SubentID=30974002

http://www.americanelements.com/thoxst.html

http://arxiv.org/pdf/physics/0404119

NIM_A535_2004_93[1]

File:NIM A590 2008 pg134 Eberhardt.pdf Prep Targets

Neutron cross sections for different elements Media:Neutron_cross_sections.pdf

http://www-nds.iaea.org/RIPL-2/

Media:n gamma cross sections at 25 keV.jpg

Media:n alpha cross section at 14.2 MeV.jpg

Media:ne cross section at 14 MeV.jpg

Media:high enegy fission x-section.jpg

Media:N_gamma_x-section_at_400_keV.jpg

Media:x-sections of reactions at 14 MeV.jpg

Media:n p x-section at 14.3MeV.jpg

Media: n gamma x-section at 14.5 MeV.jpg

Media: elastic x-section at 0.5 MeV.jpg

Media: n gamma x-section at 1 MeV.jpg

Media: n 2n x-section at 14.3 MeV.jpg

Donald James Hughes, Neutron cross sections, 2nd edition 1958, u.s.a atomic energy commission.Media:Neutron cross sections.pdf

File:NSAE 151 2005 319-334 Y.D. Lee.pdf

TGEM-2009 File:TGEM 2009.pdf

12 Volt power supply system.

http://www.lnf.infn.it/esperimenti/imagem/doc/NIMA_46128.pdf

http://electrontube.com.Media: rp097mono HV divier.pdf

http://www.cerac.com/pubs/proddata/thf4.htm#anchor550078

http://en.wikipedia.org/wiki/PC_board

http://wikipedia.org

A : concise review on THGEM detectors A.Breskin, R. Alon, M. Cortesi, R. Chechik, J. Miyamoto, V. Dangendorf, J. Maia, J. M. F. Dos Santos

GEANT4_Paticles_Models[2]

Resistors online store : http://www.justradios.com/rescart.html

RETGEMs

Media:Jinst8_02_p02012_THGEM_spark.pdf‎

Media:2010_INST_5_P03002.pdf‎

Thick GEM COBRA

Media:THGEM_COBRA_08_10.pdf‎

Media: Nucl_Phys_B_Bidault_ novel UV photon detector.pdf

Media:Mauro micro pattern gaseuos detectors.pdf

Media:Development and First Tests of GEM-Like Detectors With Resistive Electrodes.pdf

http://www.supplydivision.co.uk/genitem.htm

http://www.radioshack.com/search/index.jsp?kwCatId=&kw=24%20gauge%20wires&origkw=24%20gauge%20wires&sr=1

Thick_GEM_versus_thin_GEM_in_two_phase_argon_avalanche_detectors (HV circuit)[3]

Stainless Steel deflection [4]

Data Sheets

radioactive surface cleaner NoCount MDSD File:Radioactive surface cleaner.pdf.

Th-Xsection references

File:Th-232 fxsection Behrens 0.7-1.4MeV.pdf

File:Th-232 fxsection Blons 1975 1.2-1.8MeV.pdf

File:Th-232 fxsection ermagambetov 0-3MeV.pdf

File:Th-232 fxsection Henkel 0-9MeV.pdf

File:Th-232 fxsection Ohsawa original.pdf

File:Th-232 fxsection pankratov 3-35MeV.pdf

File:Th-232 fxsection protopopov distancefromthesource.pdf

File:Th-232 fxsection rago 12.5-18MeV.pdf

U-238-Xsection and coating references

relative cross section and calibration samples characteristics for a well determined number of fissions per second

File:Eismont relative absolute nf induced intermediate energy.pdf

U_238 cross section error analysis

INTERNATIONAL EVALUATION OF NEUTRON CROSS-SECTION STANDARDS, INTERNATIONAL ATOMIC ENERGY AGENCY,VIENNA, 2007 File:U238-xsection.pdf

U_238 (0.5-4MeV) and Th_232 (1-6MeV) fission cross section with statistical error.File:Th-232 U238 xsetion data ebars.txt

File:Pankratov fxsection Th232 U233 U235 Np237 U238 5-37MeV.pdf

Thorium Coating

ThF4 target for sputtering coatings

http://www.cerac.com/pubs/proddata/thf4.htm

Machining Uranium

Uranium will ignite in powder form

http://www.springerlink.com/content/rr072r52163x0833/

coating Uranium

[[5]]

http://cat.inist.fr/?aModele=afficheN&cpsidt=16864172

Calorimeters/Detectors: DU sheet is in wide-scale use as an absorber material in high-energy physics research at large accelerator laboratories. The high atomic number and density of DU presents a large number of atoms per unit volume to interact with the particles emerging from collisions in these detectors. Also the slight background radiation from DU enables in situ calibration of the electronic read out devices within such detectors, thereby improving the accuracy of measurement.

http://www.2spi.com/catalog/chem/depleted-uranium-products.html

[6]

[7]

IAEA Photonuclear Data Library [8]

Data Acquisition

Warren_logbook[9]

Warren_Thesis [10]

Related To Gaseous Detectors

Breakdown and Detector Failure (10/21/10)

Different kind of micro-pattern detectors

References

1- A. Bressan, M. Hocha : NIM A 424 (1999) 321—342 File:High rate behavior and discharge limits in micro-pattern detectors .pdf

2- Fonte and Peskov IEEE 1999 :File:Fundamental limitations of high rate gaseous detectors.pdf

3- B. Schmidt: NIM A 419 (1998) 230—238 File:Microstrip gas chambers Recent developments radiation damage.pdf

Ideas

1.) Can we mix resistive paste (Encre MINICO) with TH-232. We construct a "bed of nails" to place a predrilled G-10 board with a copper border. The nails fill in the holes of the G-10 to keep the paste out. Ecre MINICO is a resistive paste used for transistors.

a.) Get some resistive paste.

http://www.leggesystems.com/p-253-elimstat-uxm-ccp.aspx

Resistive glue to compare

File:Duralco 4461.pdf

http://www.ellsworth.com/conformal.html?tab=Products

http://www.ellsworth.com/display/productdetail.html?productid=764&Tab=Products

http://www.ellsworth.com/display/productdetail.html?productid=2067&Tab=Products

http://www.cotronics.com/vo/cotr/ea_electricalresistant.htm

b.) mix with a metal similar to Th-232.

c.) construct bed of 0.4 mm nails. Look for 0.4 mm diameter pins.

7/31/2009

New vendor for carbon paste.

http://www.electrapolymers.com/productItem.asp?id=33

The data sheet does not show any information about the thickness of the paste.

The company has a distributor in the usa (877)-867-9668. A phone call is expected on Sat. 8/3/2009 about the availability of the product.

TGEM Mask Design

Coating U-238 or Th-232 is essential for neutron detection in the range 2-14 MeV, but THGEM contains holes that should be protected from any coating material. So, a mask is designed to cover these holes. The holes are in drilled to be on the corners of hexagonal of 1mm side length as in the figure: