Normalization of yield data - Revision history

Hayes: /* Introduction */ Added important note that this article assumes efficiency-corrected yields

2012-09-21T13:28:50Z

Introduction: Added important note that this article assumes efficiency-corrected yields

← Older revision		Revision as of 13:28, 21 September 2012
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	==Introduction==		==Introduction==
		+
		+	''In this "Normalization of yield data" article it is assumed that the user is passing efficiency-corrected gamma-ray yields to Gosia, but there are other ways that data can be used.''

	Any arbitrary overall normalization of the gamma-ray yield data is acceptable, unless the user is trying to normalize to the collision partner's gamma-ray yields or to the elastic cross section. This is because Gosia fits one overall normalization constant to all yield data, representing the factors of beam current, beam time, etc.		Any arbitrary overall normalization of the gamma-ray yield data is acceptable, unless the user is trying to normalize to the collision partner's gamma-ray yields or to the elastic cross section. This is because Gosia fits one overall normalization constant to all yield data, representing the factors of beam current, beam time, etc.

Hayes: fixed details of the solid angle factors for clusters

2011-06-16T15:39:16Z

fixed details of the solid angle factors for clusters

← Older revision		Revision as of 15:39, 16 June 2011
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	==Ge detector solid-angle corrections==		==Ge detector solid-angle corrections==

-	If all of the Ge detectors span the same solid angle, then all of the data will be consistent if each count is efficiency-corrected by dividing by the relative efficiency <math>\epsilon (E_\gamma)</math> with an arbitrary overall normalization. However, if two data sets from different detector ''[[physical_germanium_type \| types]]'' are included, then the following additional correction is necessary, since Gosia calculates (OP,INTI) yield per unit Ge solid angle ~~to be used~~ in ~~fits~~ (OP,MINI).	+	If all of the Ge detectors span the same solid angle, then all of the data will be consistent if each count is efficiency-corrected by dividing by the relative efficiency <math>\epsilon (E_\gamma)</math> with an arbitrary overall normalization. However, if two data sets from different detector ''[[physical_germanium_type \| types]]'' are included, then the following additional correction is necessary, since Gosia calculates (OP,INTI) yield per unit Ge solid angle and expects the same yield per unit solid angle in fitting (OP,MINI).

	Gosia expects to read "corrected" yields of		Gosia expects to read "corrected" yields of
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	In cases where the overall normalization doesn't matter, the efficiency can absorb the solid angle and be taken on a scale of 0 < efficiency < 4pi, ''but the solid angle factor must not be included twice.''		In cases where the overall normalization doesn't matter, the efficiency can absorb the solid angle and be taken on a scale of 0 < efficiency < 4pi, ''but the solid angle factor must not be included twice.''

-	===Exceptions===	+	===Exceptions and warnings===

-	If the ~~counts from different types of Ge detectors are being summed into one data set, and there are no other~~ data sets (~~Ge detectors or arrays~~), ~~then~~ the ~~<math>\Delta\Omega_{~~Ge~~}</math> term amounts to only an overall normalization and can~~ be ~~neglected~~.	+	If the data sets are from detector clusters (see OP,RAW in the user manual), all of the Ge crystals in the cluster should be of the same physical type. This is because Gosia gives output and expects data from the user representing the count per unit solid angle ''of the crystal type,'' not of the total cluster solid angle.

-	The OP,RAW command can be used to pass data to Gosia without an efficiency correction. The solid angle divisors are still required.	+	It is not clear how to handle summed Ge clusters of ''different physical types'' in Gosia.
		+
		+	The OP,RAW command can be used to pass data to Gosia without an efficiency correction and/or for summed clusters. The solid angle divisors are still required, and for each cluster should be taken as <math>\Delta\Omega_{crystal}</math>—the solid angle of a single Ge detector in the cluster!

Hayes: corrected a typo in the DeltaOmega expression under "exceptions"

2011-06-15T13:30:06Z

corrected a typo in the DeltaOmega expression under "exceptions"

← Older revision		Revision as of 13:30, 15 June 2011
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	===Exceptions===		===Exceptions===

-	If the counts from different types of Ge detectors are being summed into one data set, and there are no other data sets (Ge detectors or arrays), then the <math>\Delta\Omega_{Ge})</math> term amounts to only an overall normalization and can be neglected.	+	If the counts from different types of Ge detectors are being summed into one data set, and there are no other data sets (Ge detectors or arrays), then the <math>\Delta\Omega_{Ge}</math> term amounts to only an overall normalization and can be neglected.

	The OP,RAW command can be used to pass data to Gosia without an efficiency correction. The solid angle divisors are still required.		The OP,RAW command can be used to pass data to Gosia without an efficiency correction. The solid angle divisors are still required.

Hayes: corrected math in the formula for "corrected yields"

2011-06-15T13:28:44Z

corrected math in the formula for "corrected yields"

← Older revision		Revision as of 13:28, 15 June 2011
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	If all of the Ge detectors span the same solid angle, then all of the data will be consistent if each count is efficiency-corrected by dividing by the relative efficiency <math>\epsilon (E_\gamma)</math> with an arbitrary overall normalization. However, if two data sets from different detector ''[[physical_germanium_type \| types]]'' are included, then the following additional correction is necessary, since Gosia calculates (OP,INTI) yield per unit Ge solid angle to be used in fits (OP,MINI).		If all of the Ge detectors span the same solid angle, then all of the data will be consistent if each count is efficiency-corrected by dividing by the relative efficiency <math>\epsilon (E_\gamma)</math> with an arbitrary overall normalization. However, if two data sets from different detector ''[[physical_germanium_type \| types]]'' are included, then the following additional correction is necessary, since Gosia calculates (OP,INTI) yield per unit Ge solid angle to be used in fits (OP,MINI).

-	Gosia expects to read yields of	+	Gosia expects to read "corrected" yields of

-	<math>Y = N_{raw} / (\epsilon(E_\gamma) \Delta\Omega_{Ge}</math>,	+	<math>Y = N_{raw} / [\epsilon(E_\gamma) \Delta\Omega_{Ge}]</math>,

	where <math>Y</math> is the "corrected yield," <math>N_{raw}</math> is the measured count, <math>\epsilon(E_\gamma)</math> is the relative (or absolute) Ge detector efficiency and <math>\Delta\Omega_{Ge}</math> is the solid angle subtended by the germanium detector. Here, the solid angle is in units of sr (steradians). Obviously, if all Ge detectors span the same solid angle, then the <math>\Delta\Omega_{Ge}</math> term can be absorbed into the arbitrary overall normalization.		where <math>Y</math> is the "corrected yield," <math>N_{raw}</math> is the measured count, <math>\epsilon(E_\gamma)</math> is the relative (or absolute) Ge detector efficiency and <math>\Delta\Omega_{Ge}</math> is the solid angle subtended by the germanium detector. Here, the solid angle is in units of sr (steradians). Obviously, if all Ge detectors span the same solid angle, then the <math>\Delta\Omega_{Ge}</math> term can be absorbed into the arbitrary overall normalization.

Hayes: page creation

2011-06-14T17:52:21Z

page creation

New page

==Introduction==

Any arbitrary overall normalization of the gamma-ray yield data is acceptable, unless the user is trying to normalize to the collision partner's gamma-ray yields or to the elastic cross section. This is because Gosia fits one overall normalization constant to all yield data, representing the factors of beam current, beam time, etc.

==Ge detector solid-angle corrections==

If all of the Ge detectors span the same solid angle, then all of the data will be consistent if each count is efficiency-corrected by dividing by the relative efficiency <math>\epsilon (E_\gamma)</math> with an arbitrary overall normalization. However, if two data sets from different detector ''[[physical_germanium_type | types]]'' are included, then the following additional correction is necessary, since Gosia calculates (OP,INTI) yield per unit Ge solid angle to be used in fits (OP,MINI).

Gosia expects to read yields of

<math>Y = N_{raw} / (\epsilon(E_\gamma) \Delta\Omega_{Ge}</math>,

where <math>Y</math> is the "corrected yield," <math>N_{raw}</math> is the measured count, <math>\epsilon(E_\gamma)</math> is the relative (or absolute) Ge detector efficiency and <math>\Delta\Omega_{Ge}</math> is the solid angle subtended by the germanium detector. Here, the solid angle is in units of sr (steradians). Obviously, if all Ge detectors span the same solid angle, then the <math>\Delta\Omega_{Ge}</math> term can be absorbed into the arbitrary overall normalization.

However, if two or more of the Ge detectors subtend different solid angles, the <math>\Delta\Omega_{Ge}</math> term should be included.

In cases where the overall normalization doesn't matter, the efficiency can absorb the solid angle and be taken on a scale of 0 < efficiency < 4pi, ''but the solid angle factor must not be included twice.''

===Exceptions===

If the counts from different types of Ge detectors are being summed into one data set, and there are no other data sets (Ge detectors or arrays), then the <math>\Delta\Omega_{Ge})</math> term amounts to only an overall normalization and can be neglected.

The OP,RAW command can be used to pass data to Gosia without an efficiency correction. The solid angle divisors are still required.